Ford Service Course
A MODEL T FORD SERVICE COURSE
This service course was apparently given by Ford dealers to owners and others in an effort to help them understand the workings of their new Fords. It dates from the early twenties but is applicable to almost all Model Ts. The author is unknown. WHAT IS OUR COURSE? This school has been established for the purpose o teaching the economical operation and maintenance of Ford cars.
We believe that hit-and-miss automobile driving has been one of the largest, contributors to our national reckless extravagance. In view of the millions of automobiles now in use it can readily be seen that if more intelligent and more economical principles were employed in their operation, a saving-would be effected far greater annually than all of the gasoline and fuel consumed by all the automobiles in the world.
Our course has been divided into ten lessons, each one dealing with a separate subject. These are the subjects to be taken up and the rotation in which they will be discussed.
1.General Construction and Cooling System
4.Starting and Lighting System
8.Front System and Steering Gear
9.Rear Axle Assemblies
10.General Review, Tire Care and Road Laws.p>
These lectures and demonstrations will be given in the evenings, once a week for ten weeks. Every effort has been made to make our discussions very practical and easily understood. Our continuous system of lessons makes it possible for the student to enter our school at any time. For example, one starts on the 6th lesson and finishes the remaining lessons and continues on the second term, for four weeks, at which time he will have completed the course.
WHY ESTABLISHED These lessons have been designed for the purpose of establishing with Ford owners a more intimate understanding of their cars with the view of reducing the cost of operation and up-keep.
That the Ford car has furnished transportation at the lowest possible cost up to this time, is a well established fact but we are of the belief that with a greater knowledge of his car, the Ford owner will still reduce the cost of, operation, very materially. We want you to be able to make minor adjustments, to be able to identify approaching troubles and to be able to correct them. SCHOOL FOR OWNERS Any man or woman who drives or owns a Ford car or anticipates ownership, or any mechanic who is interested in the repair of Ford cars, is eligible to our course. Any old owner will be interested in reducing the cost of operation of his present car and the prospective owners will be interested in becoming thoroughly informed before taking their car out on the road. Ford car drivers or chauffeurs will increase their earning capacity by cutting down repair bills on their employers’ cars. Drivers who have attended our classes, passed the examinations and received a diploma from our institution, we are sure, will find it easy to get and “hold down” a first class position. SCHOOL FOR MECHANICS While this course has not been established primarily to make mechanics, we will, during the classes, demonstrate as many repair “short cuts” as possible and in any instance, we will no doubt, be able to give good ideas along this line to those interested in garage repairing. It is our idea that a garageman will in the very near future, become either a Ford specialist or a general garage repair man and it is with this idea in mind that we will furnish as many ideas along shop repairing lines as our time will permit. BENEFITS WE WILL GAIN This school has been established at a great expense to our firm and with the small overhead charge that we have made, you can readily see that it is not a money-making institution. The results that we hope to gain from conducting these classes is simply a matter of increasing Ford car sales, thru rendering a real service to the Ford driving public. This school will be operated with the belief that if the Ford Owner or driver or mechanic GIVES THE FORD A FAIR CHANCE, that we, as Ford dealers, will sell a greater number of cars than ever. That the Ford car will do its part is universally acknowledged and we are here for the purpose of instructing the owners and drivers in the matter of getting the greatest possible efficiency out of their cars.
Then our position as Ford dealers, where we claim to have no competitors, will be more firmly established than ever. LEARN TO KNOW HOW On account of the limited Ford knowledge on the part of many owners, they find themselves, in some instances, at the mercy of the garageman and mechanic, who sometimes know no more than the owner himself. On the other hand, it is much more satisfactory for a legitimate, honest garageman to do business with a person who is reasonably well versed on the subject of repairing his own car.
The reliable garages in this city as well as others, spend much time in showing and trying to make customers understand and appreciate the necessity of having certain repair jobs done on their cars and in some instances, even then the owner is not thoroughly convinced. With this unfortunate condition in mind, our school has met with the approval and hearty endorsement of many of our first class garage owners already. The fact that many garage owners have enrolled in our classes as well as have many mechanics, indicates in itself that the conscientious garageman is now anxious to have the Ford driving public know their cars mechanically. It will readily be seen that the ultimate result of such a confidence will result not only in the more economical operation of Ford cars on the part of the owner but a substantial and lasting relationship will be established between Ford owner and garageman. BE FORDLY INFORMED Ford repair work, at the present time, furnishes a good percentage of the work done in the average garage and with the inevitable increase in the number of Ford cars in the future, it is only reasonable to expect that this percentage of Ford repair work will increase very rapidly. So it is important that the garageman, foreman and mechanics learn Ford cars and Ford machinery in the same terms as that of the owner or driver.
For the Ford owner to have a practical knowledge of his car means a large saving annually on repair and operation costs. We want the Ford owner or driver to get the greatest amount of satisfaction out of the employment of his car at the lowest possible cost.
We will cover the operation and up-keep of Ford cars and trucks only and would request that questions and discussions concerning other cars be withheld. We will also show you that the Ford car is not a vehicle to be used for a few months during the summer and then stored away for the rest of the year. By knowing practical methods for cold weather starting and driving you will find as much enjoyment out of driving in the winter as in the summer. Lecture Number 1 (Note:’It is advisable to have a chassis, with hood removed, in front of the class during these lectures in order that the instructor may refer to it from time to time) GENERAL CONSTRUCTION OF THE CHASSIS In order that this lecture may be perfectly clear to everyone, we will assume that many of you are entirely unfamiliar with the relationship of the various parts of the Ford chassis and their functions.
Illustration No. 1
The chassis is that part of an automobile comprising all parts except the body and the rear fenders. The chassis of an automobile can be considered in the same light as the running gear of a wagon. First we have the RADIATOR (1) which is the storage and cooling place for the water which is utilized in keeping the motor at a uniform temperature.
Then we have the MOTOR (2) itself, which is the generator of the power that propels the car. The Ford motor is of a type known as unit power plant construction, that is, the transmission is built into the motor.
The purpose of the TRANSMISSION (3) is to transmit the power thru the drive shaft to the rear axle (4). The transmission also allows a change of speed thru the gears and permits reversing direction.
Next, the UNIVERSAL JOINT (5) is the coupling between the transmission and the drive shaft. It is constructed in a manner to permit the rotating of the drive shaft at an angle to the crankshaft. This angle is necessary because the driving gears in the rear axle are lower than the motor.
The DRIVE SHAFT (6) in turn transmits the power to the DIFFERENTIAL (7) the purpose of which is to permit the rotating of one rear wheel faster than the other in turning corners, etc., thence the AXLE SHAFT (8) and the rear wheels.
The FUEL TANK (9) is placed in the highest possible position in relation to the carburetor as the flow of gasoline depends on gravity. The CARBURETOR (10) is located low on the right side of the motor, mixes the gasoline with air to form a highly explosive vapor which is then compressed and ignited in the cylinders or combustion chambers.
On the dash is the coil box containing the four COIL UNITS (11). These coil units change the primary current as it comes from the magneto, to a secondary current. From the coil units, wires lead to the COMMUTATOR or TIMER (12) the purpose of which is to distribute the ignition to the cylinders at the proper time.
The FAN (13) driven by a belt from a pulley on the crank shaft, draws air thru the radiator tubes and it also helps cool the motor.
The STEERING ASSEMBLY (14) by means of which direction of travel is obtained, turning the front wheels left or right, is fastened to the dash and to the frame by a steering post bracket. To the base of the steering post is fastened the steering gear ball arm which connects with the steering gear connecting rod which in turn actuates the spindle arm connecting rod, the spindle arms and then the front wheels.
The FRONT AXLE (15) is tilted backwards 5-1/2 degrees to obtain a castor effect and held in place by the FRONT RADIUS ROD (16). This tends to stabilize the wheels and better enables them to resist jolts and shocks.
The foregoing description has given a very general idea of the Ford chassis. With the succeeding lectures we will take up in detail the various units heretofore mentioned.
In this particular lecture we will deal with:
THE COOLING SYSTEM
SEE ILLUSTRATION NO. 2
Illustration No. 2
The extreme heat caused by the explosion of the gases in the cylinders and also the friction of the pistons on the cylinder walls, would soon cause the expansion of the pistons to such a degree that they would “seize” or stick if it were not for some adequate cooling system.
TYPES OF COOLING SYSTEMS There are two general types of cooling system used in modern automobile construction, namely, air and water. By far the most satisfactory of these types is the water cooled system as used by the Ford. Then there are two methods of circulating the water thru the motor jackets and radiators, viz., the force system and the thermo-syphon system.
FORCE SYSTEM The force system depends on a pump to carry the water from the bottom of the radiator to the inlet on the bottom of the motor water jacket, thence thru the jackets and back to the top of the radiator where it flows down thru the tubes is cooled and the process repeated. By this method the water flows at the same rate in cold weather as in hot and it is difficult to maintain a uniform motor temperature.
THERMO-SYPHON SYSTEM This thermo-syphon system as found on the Ford car depends for circulation on the natural phenomena that hot water is lighter than cold water and will seek a higher level. It is now an established fact that the best efficiency is obtained from the Ford motor when the water that is cooling it, remains just below the boiling point. Thus when a cold motor is started the heat soon causes the water to rise from the cylinder wall and the cylinder head jackets, thru the top radiator connection to the syphon or top tank on the radiator. From here it flows down thru the radiator tubes displacing the cooler water, thence on down thru the bottom radiator connection and up thru the cylinder jacket intake and around the system again. It is evident that this is the simplest and most efficient method that could be used.
RADIATOR CONSTRUCTION There are two types of radiators in common use, the cellular and the tubular. The tubular radiator employed by the Ford is much simpler and more efficient for the thermo-syphon system of cooling. It is built up of the following parts,-filler neck and cap, top or syphon tank in which is the splash plate. The body or core consists of ninety-five one-quarter inch tubes and eighty-seven fins. The “core” at the bottom fits into the bottom tank and the weight of the radiator is supported by the lower header and the bottom tank brackets.
The radiator shell slips over the top tank and sides to present a neater finish. The purpose of the top tank is to hold water to absorb any steam which may form in the jackets and to keep the upper ends of the radiator tubes covered with water. When the water level falls below the top of the tubes there is no circulation and consequently the water in the jackets will boil. In the top tank is placed what is known as the splash plate. The splash plate directs the flow of water as it comes back into the top of the radiator and prevents loss thru the overflow pipe. The overflow pipe has its outlet in the filler neck and takes care of surplus water or steam which might cause breakage of the radiator.
The purpose of the “core” is to present a cooling surface by means of the tubes and fins. The fins radiate the heat away from the tubes. The combined cooling surface exposed to the air by the fins and tubes is 63.57 square feet, which is all remarkable when the size of the “core” is considered, 19 inches long, 2-5/8 inches in breadth and 17-3/8 inches high.
CARE OF COOLING SYSTEM The average driver does not give the cooling system the attention or care that it should receive in order to get the best service from his car. The capacity of the whole system is three gallons, two gallons in the radiator and the remainder in the jackets and connections. It can readily be seen, if one or more of these tubes becomes clogged, that the efficiency of the radiator is greatly reduced. There are two general causes for the clogging of the tubes foreign matter in the water and freezing. While the radiator itself is composed of non-rusting or non-corrosive metals entirely, still a certain amount of rust and scale forms in the cylinder jackets which is carried thru the tubes. Therefore it is a good plan to thoroughly clean out the system two or three times a year.
The most practical method is to mix a half pound of soda in four gallons of hot water and fill the radiator. Run this solution through several times until all scale is removed.
PREVENTION AGAINST FREEZING From November to March, service garages receive more complaints from customers about so- called defective radiators than thru all the rest of the year. This is always due to the fact that proper precautions against freezing have not been observed. It seems hard for some drivers to understand why the largest percentage of radiators freeze up while their cars are in action. The principal reason for this is that many drivers start their cars off into the cold without first warming the water by running the motor.
If there is a solution in the radiator designed to resist 10 below zero, it will often freeze up when the car is being driven in a temperature of only 5 below zero, if the motor had not been run long enough to heat the solution sufficiently before starting the car. The solution in such cases cannot be expected to resist the circulation of cold air thru the tubes. It is a good plan to throw a robe over your radiator in extreme weather and run your motor five or ten minutes and warm the solution in your radiator before starting the car. When the solution is once warmed, it is kept so with little effort.
As we have stated, the Ford car is equipped with the thermo-syphon system of radiation and the best circulation of water is not obtained until the water has reached a near boiling point. The very nature of the thermo-syphon system, as we have explained, provides for the warm water being at the top and the cooled water at the bottom of the system, hence the lower portion of the radiator usually freezes first.
When the tubes become so clogged with ice as to stop circulation, that uncirculating part of the water left in the upper part of the radiator and cooling system, is quickly heated and forced out through the over-flow pipe by the steam pressure generated in the cylinder head. It is only a moment’s time then until the steam accumulates to such a great extent that it forces its way out through not only the overflow pipe, but the radiator cap as well and some times forces the radiator out of shape, with this extreme pressure.
When the first indications of a frozen motor appear it is advisable to stop the car, but not the motor. Then throw a robe or overcoat over the radiator and continue to run the motor slowly. If this plan is followed out you will find that the circulation is re-established in only a few minutes. Many drivers make the mistake of trying to get to a garage when signs of radiator freezing appear. This should not be done because when the tubes are once clogged with ice, they freeze very quickly and expand and burst in rapid succession. It is advisable in cold weather not to attempt to operate your car without a reasonable protection for the lower portion of the radiator at least. A hood or cardboard are the most common types of protection for that part of the Ford radiation system. When the weather becomes more extreme it is very advisable to add an alcoholic solution and so eliminate any possibility of freezing and bursting the radiator.
ABOUT KEROSENE RADIATION There are various anti-freezing solutions, such as glycerin, chemicals and some drivers have success using kerosene. This necessitates using a circulation pump and there is a certain element of danger as kerosene is a more powerful explosive than gasoline when at the boiling point.
ANTI-FREEZING COMPOUNDS Every winter brings onto the market many new anti-freezing compounds for preventing radiator annoyance. Most of these new solutions carry guarantees and most elaborate assurance that the driver is for all time rid of all radiator inconvenience. While it is true that many of these solutions will not freeze we have found that a large portion of them contain materials that eat thru the hose connections and short the motor. When this occurs there is usually no end to ignition troubles until all such materials has been removed and the cooling system entirely cleansed. We would advise that before you adopt any product for use in your radiator that you be sure it is not experimental. Be sure that it is a tried and true product. DENATURED ALCOHOL In our experience we have found that the most satisfactory anti-freezing solution is denatured alcohol. It has no injurious effects on the radiator or hose connections and when used in the proper proportions is an absolute preventive against freezing. Care must be taken to add a quart or two to the solution in the radiator every week or so, as the alcohol loses its strength thru evaporation, particularly if the water boils.
HOW MUCH ALCOHOL
Illustration No. 3 shows this. If the proportions suggested in the diagram are rigidly adhered to, no difficulty will be experienced with leaky radiator tubes or cracked cylinder heads. Too much emphasis cannot be placed on the importance of preventing freezing. A motor block may be completely ruined by one hard freeze. This is one of the unnecessary upkeep expenditures which can be easily avoided by knowing how.
CAUSES FOR RADIATOR OVERHEATING
We will now deal with the principle reasons for radiators boiling over. First look at the water level in the radiator and be sure there is enough for good circulation. Then look at the fan and see if the belt is on the pulley and not slipping. Then determine if you have been driving with the spark retarded too much or if the spark rod is disconnected, from the timer. Too rich or too light a mixture in the carburetor will also cause overheating. There are other reasons, such as carbon deposits in the motor, etc., which cause overheating and will be discussed thoroughly in the later lectures.
COLD WEATHER STARTING Particularly in the fall of the year, when we begin to have cold frosty mornings, many people will experience difficulty in starting their motors. If the following precautions are taken in starting the motor, it will be quite simple.
With the ignition switch turned off and the spark lever about 3 notches down on the quadrant and the throttle lever about 6 or 7 notches down on the quadrant, and the choke button pulled out, put your foot on the starter switch and let the motor turn over several revolutions. This will fill the cylinders with the necessary mixture of gasoline. Turn the ignition switch on the battery side and then press the starter switch again. As soon as the motor gives a few explosions, bring down the spark lever several notches and as the motor gains speed, turn the ignition switch on the magneto side. Should the motor seem to be dying down, pull choke button out and release quickly several times. Do not hold choke button out but a very short time because the motor is easily flooded. In extreme cold weather open up carburetor adjustment from a quarter to a half turn until motor gets well warmed up and then turn back to original position.
One of the reasons for a hard starting motor, is that of too heavy or worn out lubricating oil. The oil in the crank case should be changed every 500 or 1000 miles. A light medium oil should be used in the winter weather. Many Ford owners do not appreciate the importance of changing their oil regularly. Lubricating oil, after it is used a long time congeals and has a tendency to stick and corrode the discs in the high speed clutch. It is advisable in the extreme cold weather, especially if the car is left in a cold garage, to leave it in high speed after the motor has been stopped. At that time the oil is warm and if left in high speed after the motor has been stopped, the oil is squeezed out of the high speed discs which will allow free action of the discs when the clutch is disengaged upon starting the car again.
The battery should contain a maximum charge during the winter months so as to prevent its freezing and to insure prompt starting. This method of starting will never fail providing the car is supplied with gasoline and the ignition is working properly. Lecture Number 2
IGNITION As the power generated in a gasoline motor is derived from the explosion of compressed gases, it is necessary to have some convenient way of igniting these gases. The most practical method has proven to be the electric spark.
SOURCE OF IGNITION In the Ford motor there are two sources of electricity for ignition, one from a storage battery which is principally used for starting, the second from a low tension magneto, located on the flywheel. The battery current is of six volts and will excite the coil units but the coil units are designed for a current of nine volts or more, which is generated by the low tension magneto, consequently the magneto should be used for ignition when running. The current thus generated is collected by the magneto contact plug, which is located on the very top of the transmission case, directly under the coil box and delivered to the junction box on the left side of the dash then through the ignition switch and then to the four coil units in the coil box located on the dash. From the coil units the current is passed through the wire loom to four contact points in the commutator or timer which is located at the extreme front, right and lower part of motor block.
PATH OF THE CURRENT When the contact is made in the commutator, this causes a flow of the primary current through the coil units which induces a secondary current to the spark plugs. The spark plugs provide a gap across which the current will jump causing a spark in the combustion chamber which ignites the compressed gases.
CONSTRUTION OF THE MAGNETO nbsp; The Ford magneto is a flywheel type designed particularly for the Ford motor. It is an original Ford product. The Ford car being the only one which has this flywheel type of magneto.It is mounted on the flywheel itself and is protected from injury by being housed in the transmission case.
The magneto is composed of a stationery coil with sixteen spools upon it, each wound with insulated copper tape and connected by the tape. Then there are sixteen permanent horseshoe magnets on the flywheel which revolve past these coils or spools. This generates a low tension alternating current which is taken from the magneto plug or contact point. The Ford magneto is the simplest and most reliable because there are no brushes or moving contacts to become corroded or out of adjustment. CARE OF MAGNETO The most important point in the care of a Ford magneto is to keep clean oil in the crank case and carefully avoid moisture or water. Dirty oil is full of minute particles of metal and carbon which accumulate and cause short circuits in the coil windings and also short the contact plug. Great care should be taken at all times not to allow foreign material of any kind to get into the crank case. Sometimes materials get into the oil before it is put into the car and in such case, it is hard for drivers to understand just how such matter has found its way into the crank case.
If this sort of trouble is experienced, to find out whether or not the magneto plug has been short circuited proceed as follows:
PLUGS Disconnect the wire at the magneto plug and providing there is a starter and battery on the car, start the motor on the battery side and allow it to run moderately. Then place a screw driver or knife blade on the top of the plug and slide such a tool on over to where its end will touch the motor block which is the nearest metal and which connection will or will not produce a spark.
If so shorting the plug produces a spark on the screwdriver at the block or at the plug, then there is not a short circuit on the inside of the magneto plug. If shorting the plug does not produce a spark it can be concluded that a short does exist on the plug and it will be necessary to remove the plug and clean it.
Inasmuch as the magneto plug is held in place with a spring contact and sometimes difficulty is experienced in putting it back into its place, we would advise that it is taken out only when it is absolutely necessary.
CURRENT CHANGE The purpose of the coil units as was previously stated, is to transform the low tension current as it comes from the magneto to a current of high enough voltage to jump between the spark plug points. In order to explain what takes place in the coil unit and how it is accomplished it will be necessary to learn the meaning of a few common electrical terms.
ALTERNATING CURRENT is an electrical current which continually changes its direction of travel. It will not charge the battery as it alternates in polarity.
POLARITY is an electrical condition. The terminals on a battery, like the poles of a magnet are said to possess positive and negative polarity.
DIRECT CURRENT is an electrical current traveling in one direction only.
The AMPERE is the unit of the amount of flow of electrical current.
The VOLT is the unit of pressure of electrical current.
LOW TENSION CURRENT is electric current under low pressure or voltage, it is the type of current supplied by a battery or a Ford magneto.
HIGH TENSION CURRENT is electrical current under high pressure or voltage, it is the type of current in the spark plug wires.
COIL UNITS The coil unit contains a primary and secondary coil, a condenser, a soft iron core, and the upper and lower bridge. The transformation or induction of the current is caused by producing a current in one wire by another current in another wire near the first but absolutely insulated from it.
It is interesting to note the care and accuracy used in building up the Coils of the unit. The core is made of 165 pieces of soft iron wire insulated with heavy paper from the primary coil which is wound around it.
The primary coil is made up of a comparatively few turns of copper insulated wire and then soaked in hot paraffin and rosin. The secondary coil is made up of 6,000 feet of enameled copper wire with insulation between each layer. It is wrapped in two spools to reduce the diameter of the coil.
The secondary coil is heated to 220 degrees Fahrenheit for twenty minutes in a vacuum to be sure and rid the coil of any moisture, it is then dipped in hot wax; the primary coil is wrapped with wax paper and placed in the secondary coil, completing the induction coil.
The CONDENSER serves as a regulator of the flow of current. It is built up of two pieces of tin foil seven feet long and three and one-half inches wide. They are placed one on the other insulated by waxed paper and rolled together. The condenser is then freed from moisture and boiled in paraffin.
These parts are placed in the coil box in their proper position and tar is poured around them to hold them in place and insulate them from each other. The upper bridge on top of the coil is made of brass. Riveted to it is a spring of bronze containing a tungsten steel point and held from the bridge by a spacer rivet. The lower bridge is made of copper. An armature of Swedish steel with a tungsten point on one side is fastened to the bridge by two screws. The point on the armature should be on a direct line with the point on the cushion spring. The coil is adjusted by changing the tension on the armature.
SEE ILLUSTRATION NO No. 4?/p>
The diagram shows the construction of a coil unit. The coil units as a rule give very little trouble.
ADJUSTMENT OF COIL UNITS
It is important to see that the tungsten steel contact points are not pitted or rough. It is also necessary to have the proper tension on the vibrator or armature spring. Do not attempt to adjust the coils without a coil tester, as it is almost impossible to get satisfactory results.
Such a tester can be found in all Ford service stations and usually there is no charge for such an inspection and adjustment. Improper adjustments burn out the points quickly and make it almost impossible to start the motor.
In washing the car care must be taken to keep water from the coil units, coil boxes and wires leading to the coils as water causes a short circuit.
Illustration No. 4
THE TIMER From the coil units wires lead to the commutator or timer. These wires are encased in what is called the loom. The commutator wires are wound with black, red, blue and green insulation to distinguish them from one another.
The commutator regulates the order and the time that the spark occurs at the spark plug in the cylinder. It is composed of the cover, roller brush, shaft and four segments and terminals. The segments are insulated from each other by a fiber ring. The roller brush revolving on the end of the cam shaft, comes in contact with the segments and completes the circuit. The cover is connected by a pull rod to the spark lever below the steering wheel on the quadrant.
The spark is advanced or retarded by moving the spark lever up and down which in turn changes the position of the relation to the roller brush.
SEE ILLUSTRATION NO. 5 The diagram shows the complete path of the current time it leaves the magneto until it reaches the spark plugs.
A large percentage of ignition troubles are due to faulty commutators. This again is due to t he fact that it is neglected.
Illustration No. 5
CARE OF TIMER The commutator should be oiled with a good light oil every two or three hundred miles. It also should be thoroughly cleaned out at frequent intervals as the old oil congeals and forms insulation over the contact segments, which causes the motor to start with difficulty and to “miss”. This trouble will be noticed particularly in cold weather.
In winter weather it is advisable to add a little kerosene to the oil put into the timer as the kerosene tends to cut the oil and so prevents the congealing of stiff cold oil over the contacts. It is advisable to keep this mixture in the small oil can supplied with your car.
The segments and fiber ring also become rough and worn so that the roller makes irregular contact. When this condition exists, about the only remedy is to replace the timer case and examine the roller, arm and spring, for a worn roller will soon ruin a new case. Satisfactory results are not obtained from timer oases that are put on a lathe and turned down or ground with a fine emery wheel.
USE GENUINE FORD PARTS Right in this connection it will be well to mention that the accessory market is flooded with various makes of so-called “better Ford Timers.” Absolutely the best results are obtained from the genuine Ford commutator and the Ford roller brush. They are simpler, wear longer, and give better all around service.
Now as the current is grounded in the commutator the secondary current flows from the coil units to the spark plugs thru the spark plug wires.
CONSTRUCTION OF SPARK PLUGS The spark plugs provide a gap in the combustion chamber jump across, making a hot spark for the secondary current to which ignites the gas. The plug is composed of the center wire or electrode, the porcelain, the shell and side wire, lock nut and gasket. The gap between the side wire should be exactly 1/32 of an inch.
The spark plugs are probably the most abused and the least deserving; of abuse of any part of the Ford car. Because they are easily accessible, when the motor goes wrong, first, out come the plugs. Consequently, unless great care is taken in cleaning the plugs, setting the points, and replacing them, the car runs worse than it did before they were removed.
CARE OF SPARK PLUGS In taking out the plugs and dissembling them, care must be taken not to crack the porcelain or destroy the gaskets, clean the carbon off the shell and electrodes by using the wire brush and gasoline or kerosene. Brighten the points of the electrode and side wire with emery paper, but do not use emery paper on the porcelain as it destroys the glazing and causes it to collect soot more easily. A fine double nought sand paper may be used without injurious effects.
Examine the porcelain for cracks. If evidence of cracks are discovered loosen the small nut on the top of the electrode and attempt to bend the porcelain between the fingers. This will determine if it is broken.
In assembling the plug see that the gaskets are in proper positions and screw the lock nut down firmly. Then adjust the gap to 1/32 of an inch using a steel shim for a gauge if available as it is very important to have the spark plugs accurate.
WHEN YOUR MOTOR MISSES When symptoms of ignition troubles occur such as the motor failing to start, or missing badly, first go over all terminals and see that connections are tight. Look for worn insulation on the wires, particularly the commutator wire. Then, to test the spark plugs for fouling or missing, if the motor can be started, remove the cover of the coil box and hold down the vibrators of three different coil units at a time. In this manner it can be determined by the explosions which spark plug is not firing.
The first coil unit to the right serves the number one cylinder which is the front cylinder, and the order is carried thru.
TESTING THE COILS The coils can only be tested accurately by a coil tester as was previously stated. Be sure that your coils are adjusted properly and then leave them alone as they hold their proper adjustments a long time.
Before removing the magneto plug to see if it has been shorted by some foreign matter, make the test referred to, earlier in this lecture. In general, in locating trouble and correcting it, go about it systematically. Trace the trouble down and correct it. Do not start at once to overhaul the nearest convenient part, until you discover where the fault lies.
With the advice given in this lecture and with the help of the diagrams, ignition troubles should be easily detected and corrected. Lecture Number 3
THE FUEL Experiments with various gases and liquids have proven that the most practical fuel to use in this country for automobile motors is gasoline. It can be conveniently stored in a comparatively small amount of space and it is not so volatile that there is any appreciable loss when kept in covered tanks.
A liquid is said to be volatile when it turns to vapor or gas on being exposed to the air. Gasoline is volatile at ordinary temperatures, so the biggest problem in obtaining the explosion in the motor is to mix the gasoline and air in the proper proportions, to have the most explosive mixture. This problem is taken care of by the carburetor. But in order to have the carburetor function properly, there must be a continuous, steady supply of gasoline.
GRAVITY FEED The Ford car again uses the simplest and most effective method of feeding this supply, that is what is known as gravity feed. In other words, the gasoline tank in the various models, is placed in such a position, in relation to the carburetor that no matter what angle the car is in, the tank will be higher than the carburetor.
CONSTRUCTION OF GAS TANK The gasoline tank is constructed of leaded sheet iron with all seams soldered. It is given rigid inspection and air tested at the factory. In the oval tank and square tank as well, are what is known as baffle plates which prevent the bursting of the tank by the splashing of the gasoline. Instances have been known, in the repair of gasoline tanks after a wreck, where these partitions or plates have been left out. This should not be done as the plates would not be included in the design of the tank if they did not serve a good purpose. If the gasoline was allowed to “slush” back and forth freely, it would have a tendency to open the seams in the ends of the tank.
CARE OF SEDIMENT BULB At the center and base of the tank in the fuel line is located the sediment bulb. In this bulb is a fine wire gauge strainer which removes the dirt and water from the gasoline before it is fed to the carburetor. As the sediment and water soon collect in quantities, it is necessary to drain the bulb, three or four times a year. This should particularly be attended to in the winter time as the bulb is apt to freeze and crack.
From the sediment bulb the gasoline is lead to the carburetor by a quarter-inch copper tube.
PURPOSE OF CARBURETOR The carburetor is an ingenious device which mixes and measures the air and gasoline in the proper proportions to form a gas that will be the most explosive at all engine speeds.
The principal parts of the carburetor are the float chamber, which contains the cork float and inlet needle valve, the spray nozzle, the spray needle, the mixing chamber, the primary air inlet, the choke valve, the choke or strangling tube, the low speed tube, the overflow hole, and the throttle valve.
The carburetors which come as standard equipment on all Ford cars are the Holley and the Kingston. As they are very similar in construction, a general consideration of the carburetor will cover the important points of both.
The gasoline is first admitted to the float chamber where it is kept at the proper level to feed the spray nozzle by the inlet needle valve. The inlet needle valve is operated by the cork float which rises and falls with the gasoline level. The proper level is about 1/16 of an inch below the spray nozzle.
The suction of the pistons in the cylinders draws the gasoline out of the float chamber thru the spray nozzle in the form of a spray. The spray nozzle is a hole 1/16 of an inch long. The upper one-thirty second of an inch is tapered at a thirty degree angle to spray the gasoline and to receive the point of the spray needle. The spray needle has a hand adjustment on the dash and is the means of regulating the amount of gasoline in the mixture. Around the spray nozzle is what is known as the mixing chamber, as it is where the sprayed gasoline and air combine to form the explosive gas. The air is admitted by the primary air inlet which is designed to admit a certain set supply.
In the primary inlet is a choke valve which is held wide open by a coil spring on the choke lever. This is the valve which the driver closes by the lever on the dash or the wire in front of the radiator when starting the motor. This shuts off the air supply and allows a richer mixture to enter the cylinders.
The strangling tube or the Venturi tube is where the air passage narrows around the spray nozzle increasing the air velocity and the suction. Leading from the spray nozzle up thru the Venturi tube with an opening just inside the throttle valve in the intake, is the low speed tube. The low speed tube allows a rich mixture of gas to be drawn right into the cylinders when starting the car or when idling.
SEE ILLUSTRATION NO. 6
The diagram shows a cross section of the sediment bulb and the carburetor.
Illustration No. 6
The throttle valve is a butterfly valve controlled by the throttle lever on the steering post quadrant. This permits the regulation of the amount of mixture admitted to the cylinders, thus controlling the speed. There is an adjustment screw on the throttle valve lever which holds the valve partly open and prevents the stalling of the motor.
As the mixture passes the throttle valve it is passed to cylinders thru the intake manifold, which has a branch to each cylinder combustion chamber.
ADJUSTMENT OF CARBURETOR The type of carburetor used on the Ford is known as automatic. That is free from the various complicated adjustments that are found on most carburetors. The only adjustment necessary for the driver to familiarize himself with, is the spray needle valve which controls the amount of gasoline admitted to the mixing chamber.
The mixture is said to be “lean” when there is too much air and not enough gasoline. This condition may be noted by missing and back-firing of the motor. The mixture is said to be “rich” when there is too much gasoline and not enough air. This condition is manifested by the motor choking and missing at slow speeds and a jerky galloping motion of the car. The best way to obtain the proper mixture or adjustment is to turn the needle valve down to the right until it rests lightly in the valve seat. Do not turn it down hard as this will score the point and destroy the monel metal seat. Then turn the valve open to the left one full turn. This will permit the motor to be started.
IMPORTANCE OF PROPER ADJUSTMENT Then with the motor running, turn the valve to the right until the motor starts to backfire and miss with too “lean” a mixture, then turn to the left again until the motor runs at its maximum speed.
It is one of the most important points in the economical operation of a Ford car to be able to adjust the carburetor. When the carburetor is adjusted properly it is using from 17 to 14 parts of air to 1 part of gasoline. Too rich a mixture will cause the motor to run poorly just as readily as too lean a mixture.
A rich mixture may be detected by a black smoke from the exhaust and a disagreeable odor, or when driving there will be a jerky galloping motion of the car. It will also cause the motor to heat up as there are more heat units generated and the explosion does not give a complete combustion of the gases, causing carbon deposits to form on the pistons, valves and cylinder walls.
USE THE GENUINE FORD CARBURETOR It will be well to mention at this time that undoubtedly the carburetors which come on the Ford car as standard equipment, will give the best all around service. The Ford Motor Company maintains an elaborate experimental department which is constantly trying out new ideas for the betterment of the car. So it is only natural to suppose that if there was a better carburetor it would be included in the original design of the car.
Other carburetors than the Ford are in the first place usually much more expensive, and too, generally have several delicate adjustments which are a source of constant trouble.
REGARDING CARBURETOR ADJUSTMENT There is on the market, also, various kinds of gas saving attachments and “pre-heaters”, etc. There probably is merit in some of these articles, but as a rule they are more of a nuisance than an aid. If you must decorate your car with accessories, do not put on things which will vitally affect its operation. This applies particularly to the carburetor as the carburetor is the “heart” of the car.
Good drivers obtain better mileage on long trips where a pretty good speed is maintained, by turning the needle valve nearly a quarter turn to the right, or more if it will permit. Then of course, after the motor has been stopped, to start again, the valve must be turned back to the left.
On cold mornings or when the car has been left standing for some length of time, it also aids in starting, to give the valve a quarter turn to the left, or not to exceed one-half a turn. Then after the motor has been heated up, return the valve to its usual running adjustment.
Particularly in cold weather, see that the hot air pipe that takes hot air from around the exhaust pipe and conducts it to the carburetor, is firmly in place. This aids in the vaporizing of the gasoline and allows a “leaner” mixture to be used.
CARE OF THE FUEL SYSTEM The fuel system in general needs no particular care except the occasional draining of the sediment bulb as mentioned before and the drain cock in the bottom of the float chamber. It is good economy to use a good grade of gasoline as better mileage is obtained and carbon deposits do not form so quickly.
KINDS OF GASOLINE On long tours, when it is necessary to use various grades of gasoline, it will be noticed that the car will run better when the carburetor is adjusted to meet these differences in the gasoline. All gasoline is distilled from petroleum according to the refining processes to which they are subjected various gasoline possesses different initial and end points.
The most economical gasoline is the one which will give the most powerful explosion, with the smallest amount of carbon deposit, and a relatively small loss due to evaporation. The only way to improve gasoline is to put a higher grade of gasoline in it.
Do not use any of these so-called gasoline intensifiers or the various patent tablets which, when put into the tank, are supposed to increase the power and mileage of the car. They are all designed on P.T. Barnum’s fundamental principal that “there is a fool born every minute.” These substances not only do not improve the gasoline but they actually decrease its efficiency, and in some instances, have an injurious effect on the lining of the gasoline tank and the carburetor. If some slight addition to gasoline would improve it, in the manner claimed for by these patent articles, it is only natural to suppose that large competing oil companies would manufacture gasoline containing ingredients of such a nature.
Sometimes in the winter, water collects in the carburetor and the sediment bulb and freezes, thus stopping up the line. They may be easily thawed out by applying hot cloths.
CLOGGED GASOLINE LINE If a small piece of grit or dirt should happen to get in to the spray nozzle, causing the motor to slow up and misfire, it can usually be removed by opening the needle valve a half turn and giving the throttle lever one or two quick jerks. Sometimes tapping on the bowl or float chamber with the pliers will dislodge the dirt. Also opening the drain cook in the bottom of the float chamber and allowing the gasoline to run thru freely will help to remove these small particles.
Occasionally some obstruction gets into the copper tube leading from the tank to the carburetor. This will be noticed by the motor missing or stopping entirely. By opening the drain cock in the bottom of the bowl of the carburetor, it can be determined if the gasoline is feeding properly. If the tube is clogged up, first shut off the gasoline under the tank and then disconnect the feed pipe from the carburetor and the gas tank. If available, use the tire air pressure to clear out the pipe or usually just blowing thru it will remove the obstruction.
It is also important to keep the unions between the sediment bulb ,and the copper tube and the carburetor turned up firmly. Vibration sometimes causes these unions to loosen up and gasoline is lost before the cause is discovered. But if the proper importance is attached to the adjustment of the carburetor for varying temperature and driving conditions, one of the main causes for unnecessary expense in the operation of Ford cars can be eliminated. Lecture Number 4
STARTING AND LIGHTING SYSTEM
For several years previous to the designing of the Ford starter, there were on the market, many starting and lighting systems for the Ford car, which were all more or less unsuccessful because the Ford motor at that time was not constructed in a manner to make the use of an electrical starter practical. These starters required the use of belts and chains, etc. and were at the best, a make shift outfit.
FORD’S OWN STARTER When the Ford engineers designed the F. A. two unit starting and lighting system, they worked out a system that was simple, efficient and easy to repair, with all parts standardized and quick to obtain at authorized service stations.
PRINCIPAL PARTS This system consists of the generator, out-out, starting motor, combination switch, ammeter, starting switch, lights, wiring and the storage battery.
The GENERATOR is a small dynamo located on the right side of the motor with its armature shaft geared in with the large cam shaft gear.
PURPOSE OF GENERATOR Its purpose is to recharge the storage battery which would otherwise “run down”. It is geared 1-1/2 to 1, that is when the crank shaft is turning 1000 revolutions, the generator armature is turning 1500 revolutions.
The principle parts are the yoke, the poles, the field coils, the armature, the armature coils, the commutator, and the brushes.
CONSTRUCTION OF GENERATOR The yoke is the name applied to the housing of the generator. Around the inner surface are placed the four iron shoes which are the poles. These poles are the magnets around which are wound the field coils. This produces a magnetic field in which the armature revolves. The armature assembly is composed of a laminated soft iron core around which are wound 21 coils of ten turns each. These coils produce the charging current. On the armature shaft are 21 copper segments which form the generator commutator. These segments collect the current from the armature coils. One end of each coil is connected to a segment and the other end is connected to the eleventh segment around the commutator. Thus to each segment is connected one end of two different coils.
THE CARBON BRUSHES The current is taken off the commutator by three carbon brushes which are supported in metal sockets called brush holders and held against the commutator, by springs. Two are called the main brushes, one of which is positive and the other negative. The third and smaller brush is positive. The brush holders are supported by the brush ring. The negative brush holder is grounded to the brush ring while the other main brush holder and the third one are insulated from it.
The armature being geared to the crankshaft, revolves all the while the motor is running, so it is supported by ball bearings at both ends.
WHAT PRODUCES THE CURRENT The generator produces an electric current by the revolving of the armature coils in a magnetic field. The magnetic field in the generator differs from the one in the magneto, in that the magnets in the generator are not permanent but are what is called electro-magnets. That is, they are not highly magnetic unless a current is passing thru them. However, they do retain enough magnetism to start the generator, this is known as residual magnetism. At times this residual magnetism is destroyed and the generator becomes dead. In this event the battery current will remagnetize the coils by disconnecting the wire to the ammeter and the cut-out for 15 or 20 seconds and attaching it directly to the generator.
TO REGULATE THE GENERATOR To regulate the current output of the generator, the third or smaller brush is moved on the brush ring. To increase the output it is moved in the same direction as the armature rotation, to decrease, the opposite direction. To properly charge the battery, the generator must give a steady constant current which never runs over twelve amperes at any speed. It is the purpose of the third brush to regulate this current. The current which charges the battery is taken from the commutator by the large positive brush. Then a second current or shunt field current is taken off the commutator by the third brush. The amount of charging current then, is regulated by the position of the third brush in relation to the negative or grounded brush.
CARE OF GENERATOR If the hand on the ammeter starts to show a charge with the lights off, at a speed of about ten miles an hour, and registers up to ten or eleven amperes at a speed of twenty-five miles and does not exceed twelve amperes at higher speeds, the driver can be certain that his generator is operating properly.
If the ammeter shows a discharge when the motor is running, disconnect the wire from the out-out to the ammeter. Then if the hand drops back to zero, the trouble is undoubtedly in the out-out. Ground the generator by connecting a wire from the generator contact post to one of the screws in the yoke. This will prevent the generator coils, etc., from being burnt out by current which is generated and not utilized. Then go immediately to the nearest service station and have your trouble repaired.
If the ammeter hand vibrates or does not show charge: First, see if all connections are tight. If this does not remedy the trouble, it is better to let an experienced generator man take care of you.
There are no particular precautions to be taken in the care of the generator except those mentioned. There is a place provided on the end of the generator to oil the bearing on that end, but the tendency is to over oil by most drivers. Too much oil on this bearing causes it to work thru and corrode the segments of the generator commutator. This is a very common trouble and can be easily avoided.
It is not advisable for the average driver to attempt any repairs or adjustments on the generator. By allowing only skilled electricians to make these adjustments much better results will be obtained.
THE CUT-OUT The cut-out is a small device located on the top of the generator. Its purpose is to open the circuit when the motor is stopped, to prevent the battery from discharging thru the generator. It also closes the charging circuit when the voltage of the generator is greater than that of the battery. It is composed of a fine coil of wire 1300 turns around an iron core and a heavy coil of ten turns.
ACTION OF CUT-OUT When the motor is started, the current flows thru the fine coil, magnetizes the core and pulls the points of the cut-out together. The charging current also passes thru the heavy coil which works with the fine coil and magnetizes the core to greater strength so that the points stay shut as long as the current is flowing. When the current stops, the core loses its magnetism and the points pull apart again.
As the cut-outs are accurately tested at the factory to close at 700 R.P.M. and open when there is no current flowing, it is not recommended that any adjustment be made except by experts.
In case the ammeter hand shows a discharge when the car is stopped, the trouble is usually due to the points in the out-out being stuck together or a short-circuit caused by the out-out cover. By tapping lightly on the out-out cover with a screw driver or a pair of pliers, the trouble is often remedied. However, the out-out should be inspected at a service garage as soon as convenient, to avoid the occurrence of the same trouble.
THE STARTING MOTOR The starting motor is bolted onto the transmission cover on the left side of the motor. Its purpose is to crank the motor. It is very similar to the generator in construction except that it has two negative and two positive brushes and the armature and field coil wires are much larger. Then, too, the bearings are babbitt instead of ball bearing as the starting motor is only in operation when cranking the engine.
When the current is sent thru the starting motor it is divided, half to the field coils on one side and half to the field coils on the other side, as less resistance is offered. The current then passes to the positive brushes, to the commutator, to the armature coils, then to the negative brushes which are grounded. The current magnetizes the field coils and then as it passes thru the armature; poles are set up in the core. The magnetic attraction of the field poles and armature poles is what causes the starting motor armature to revolve.
It takes from 250 to 600 amperes to crank the engine by the starting motor and as the battery is an 80 ampere hour storage battery, it can readily be seen that continued pressure on the starter button would soon completely discharge the battery.
THE BENDIX ASSEMBLY The starting motor armature shaft is prolonged to accommodate the Bendix assembly. The Bendix automatically connects and disconnects the starting motor with the gear teeth on the flywheel of the engine. It has a spur gear with a spiral thread in its bore which meshes with a spiral thread on the shaft. When the armature shaft rotates, it causes the gear to travel along the shaft until it engages with the fly-wheel thus cranking the engine.
When the engine starts to run under its own power the flywheel gear turns faster than the starter gear which forces the starter gear back along the spiral thread until it is out of mesh with the flywheel.
A heavy spring absorbs the initial shook when the starter gear engages and prevents twisting or breaking of the armature shaft.
When starting the car always remember to have the spark retarded, as the motor is otherwise apt to “kick back” and break this Bendix spring. It is just as important to have the spark retarded when starting with the starter as when cranking the car.
If when starting the car, the starter does not respond and it seems impossible to crank it by hand, probably the Bendix gear has not meshed properly with the gear on the flywheel causing them to lock. Do not continue to press the starter button as this will tend to lock the gears all the harder. Shut off the ignition switch, put the car in high gear and take hold of the rear wheel and jerk the car backwards. This will have a tendency to reverse the direction of the Bendix gear and unlock it. Sometimes this will take quite a little effort but as soon as the gear is released the car will pull back readily.
PURPOSE OF STORAGE BATTERY The storage battery which is used for starting and lighting purposes, is not at all complicated. If it is properly understood and cared for it will save a great deal of trouble for the Ford driver. Contrary to the general idea the storage battery does not store up electric current. But when two metals of varying density are placed in acid and a connection made between them, an electric current will flow from the metal of higher density or the positive, to the metal of lower density or the negative until the charge in each one is equal. This is exactly what takes place in the cells of a battery.
CONSTRUCTION OF BATTERY The standard battery equipment on the Ford car is a three cell six volt type. The cells are composed of hard rubber jars. The metal plates used are of lead. The positive plates have peroxide of lead compressed in them and the negative plates are what is known as sponge lead. The acid used, is sulphuric acid and distilled water, this is known as electrolyte. The negative and positive plates are insulated from each other by wooden separators. The cells are arranged in series, and each cell has about 2 volts pressure so the Ford battery has about six volts pressure.
CHARGED AND DISCHARGED BATTERIES When the circuit is closed between the positive and negative poles or terminals of the battery, the acid in the electrolyte unites with the active material of the plates and starts a flow of current from the positive to the negative. This action causes the plates to become sulphated or coated with lead sulphate in proportion to the amount and rate of discharge.
When a battery is said to be completely discharged, it simply means that the plates have become covered with sulphate and that most of the acid has united with the plates leaving just the water of the electrolyte solution. The sulphate should be removed before it hardens. This is accomplished by sending a direct current back thru the battery the other way which drives the acid out of the plates back into the electrolyte, thus raising its specific gravity. By specific gravity is meant the relative weight of a cubic foot of a substance in comparison to a cubic foot of water. The specific gravity of water is 1.000 of sulphuric acid 1.835. Therefore, electrolyte to have the proper mixture of distilled water and sulphuric acid should have a specific gravity reading between 1.275 and 1.300. This gravity test is taken by an instrument palled a hydrometer. A hydrometer is a glass syringe in which is a floater which is weighted in a manner to float with the upper end of a scale reading 1.000 at the surface of distilled water.
CARE OF STORAGE BATTERY To properly care for a battery it should be tested every two weeks. Remove the filler plugs and see if the solution in each cell is completely covering the plates and is up to the bottom of the filling tubes. If not, add distilled water. Do not test the gravity of the solution until the water has become thoroughly mixed in by running the car.
To test the gravity draw up enough of the solution in the hydrometer to float the indicator. When the cell being tested reads 1.270 or more, it is fully charged. When it reads less than 1.225 but more than 1.150 it is completely discharged. If one cell tests 50 points different from the others the battery should receive skilled attention at once. Do not allow the battery to become less than one-half discharged. Particularly in the winter it should be kept fully charged or it will freeze.
If the top of the battery or the terminals become corroded, care should be taken to wash off the corrosion with a rag moistened with ammonia. Then grease the terminals with vaseline or heavy grease.
Use reason when starting your car and do not keep the starter switch on for a long period. Remember it takes about a half hour steady driving to replace the charge for one starting. Be sure and keep the battery clamps tight or the vibration will cause cracked jars and loose terminals. Do not neglect your battery, do not wait until it is completely run down or fails to turn your motor over, before you bring it to the service man, and you will save yourself unnecessary expense.
WIRING OF STARTING AND LIGHTING SYSTEM The wiring of the starting and lighting system is of a type known as “one wire.” This eliminates the complications of a two-wire system and is less expensive. It simply means that there is one power wire to each object that is utilizing current and each object is grounded to the frame. As one terminal of the battery is grounded to the frame, this completes the circuit.
The lamps are con-nected in parallel instead of in series, so that the burning out of one will not effect the others. The headlamp bulbs are 6-8 volt double filament type. The double filament necessitates two wires to each head lamp.
The wire from the battery to the starter button and from the starter button to the starter motor is a heavy cable due to the fact that in cranking the car the starter motor requires heavy amperage from the battery which would burn out a smaller wire.
The electric system is controlled by the combination lighting and ignition switch on the instrument board. On the dash under the hood is located the junction box which serves as a distributing point for the wires to the various lamps, etc.
SEE ILLUSTRATION NO. 7
The diagram better shows the entire starting and lighting system.
Illistration No. 7
Usually starting and lighting troubles can all be traced back to the battery. If the battery is kept in good shape and attention is paid to the ammeter, so that the generator is kept charging, little trouble should be experienced. It-is a good plan to go over all terminals and wiring at regular intervals and see that all connections are tight and that insulations are not worn. Always carry a roll of rubberized friction tape in your tool kit, then you will be prepared in case of emergency to cover worn or defective wiring and prevent short circuits.
But the simplicity and accessibility of the Ford starting and lighting system, which characterizes the construction of the whole car, makes it easy to take care of, if a few practical instructions are heeded.
Lecture Number 5
PRINCIPAL OF INTERNAL COMBUSTION ENGINE In order to thoroughly understand the construction and operation of the Ford Model T Motor, it will be necessary to understand something of the principles involved in the ordinary four cycle, internal combustion, gasoline engine. By internal combustion engine is meant a type of motor in which the heat which generates the power is produced in the engine itself.
An example of the external combustion type is the steam engine, as the heat which produces power is outside the engine under the boiler. In a gasoline engine the combustion or burning of fuel, which is gasoline, takes place inside the cylinder of the motor. This combustion takes place so quickly and forcibly that it is known as an explosion. The explosion or force of the expansion of the gases is exerted on the top of the pistons which are sent in a downward motion. This up and down motion or reciprocating motion is changed to a rotary motion so that the power can be transmitted to the wheels, by the connecting rods and the crankshaft. The connecting rods transmit the movement of the pistons to the crankshaft.
To obtain the rapid suction, compression, explosion and expulsion of the gases requires a series of four cycles or events.
THE FOUR CYCLES This series of events is completed during two revolutions of the crank shaft, or four strokes of the piston.
1. The downward INTAKE or SUCTION STROKE during which time the cylinder sucks in the mixture of explosive gas from the carburetor.
2. The upward COMPRESSION STROKE, during which the mixture is compressed in the cylinder and prepared for ignition which occurs at the top of the stroke.
3. The rapid expansion of the compressed gases when ignited, forces the piston downward in the POWER STROKE.
4. The upward movement of the piston forces out the burned gases, this is the EXHAUST STROKE.
SEE ILLUSTRATION NO. 8
The diagram shows what takes place in one cylinder during the four cycles or two complete revolutions of the crankshaft.
CONSTRUCTION OF MOTOR
We will now take up the names of various parts of the Model T motor and their functions.
The CYLINDER CASE or CYLINDER BLOCK, as it is more commonly called, is an iron casting which contains the four cylinder bores and their water jackets, eight valve ports (two for each cylinder, intake and exhaust) and the manifold pass-ages, valve stem guides, camshaft bearing bushing supports and crankshaft bearing supports.
The cylinder head is cast separately and bolted on to the cylinder block by fifteen bolts. This makes the pistons and valves readily accessible and facilitates the cleaning out of carbon deposits.
The pistons slide up and down in the cylinder bores, so great accuracy is used in boring and reaming the cylinders to a diameter 3.748 inches to 3.749 inches. They are then rolled and polished to a diameter of 3.750 inches by a special tool which produces a hard smooth surface to eliminate friction as much as possible.
Illustration No. 8
VALVES The eight valve ports are beveled or counter-sunk to form a seat for the valves. The face of the bevel is convex profile which gives a hairline contact with the flat seat of the valves, and lessens the chance for particles of carbon to spoil the seating of the valves.
There are five steam holes in the top face of the cylinder block which connect with five holes in the cylinder head and allow the steam to escape which might collect in the lower jackets and impede circulation. There are three holes for the circulation of the water between the cylinder wall and the cylinder head jackets.
MAIN CRANK SHAFT BEARINGS On the lower side of the cylinder block, cast in the block, are the upper halves of the three main crankshaft bearing supports. The lining of these supports is babbitt metal which really forms the bearing surface. They are shaped like one-half of a cylinder. The main bearing caps similarly shaped and lined with “babbitt” complete the main crankshaft bearings when bolted in place.
THE CRANK CASE The cylinder block is bolted to the crank case which is the base of the three point suspension of the engine. It is constructed of pressed steel which gives it strength and lightness. The forward end of the case is fastened through the trunnion block to the front cross number of the frame. The trunnion block permits the crank case to stay in alignment in the various positions of the chassis. The crank case is supported in the rear at both sides, by the crank case arms which are fastened to the side members of the frame.
VALVE GUIDES AND SPRINGS The valves are fitted in and guided by the valve guides in the cylinder block. The valve stems are cold rolled steel and the heads are cast iron.
The valves are held seated at a pressure of 20 lbs. by the valve springs. The upper end of the springs rest on the guide bosses on the block and the lower end is fixed to the valve stem by a collar and a pin passing through a hole in the end of the stem.
CRANKSHAFT The crankshaft is a drop forging of vanadium steel with three main bearings and four crank throws. The main bearings have a 3/10 inch radius machined at their edges which takes care of end thrust and tends to make the crankshaft stronger. Keyed to the front end of the crankshaft by a Woodruff key is a small 24 tooth spiral gear which meshes with a larger gear on the end of the cam shaft.
CAM SHAFT AND GEARS The purpose of the cam shaft is to raise the valves from their seats at the proper time to admit the explosive mixture, and release the exhaust gases. The cam shaft timing gear has forty eight teeth, which cause it to revolve half as fast as the crank shaft.
There are eight pear-shaped cams machined on the shaft which operate against the push rods. The push rods in turn open the valves.
PISTONS The pistons are gray iron castings. Necessarily of softer material than the cylinders in order to avoid scoring them. Near the top of the pistons are two grooves, and in the “skirt” or lower down on the piston is another groove. In these grooves are placed spring rings or piston rings which prevent the escape of gases past the pistons.
CONNECTING RODS The upper end of the connecting rod is fastened to the piston, on the piston pin or wrist pin which is a steel tube fitted with a bronze bearing, into a hole bored horizontally in the piston. The Model T connecting rod is a vanadium steel forging of “I” beam type. The lower end is fastened to the crankshaft bearing by a split bearing with a babbitt bushing.
The fitting of the pistons, wrist pins and connecting rods is a very important operation and must be skillfully and carefully done. Poorly fitted pistons and connecting rods cause knocks and a noisy motor.
FITTING PISTON RINGS The pistons are ten thousandths smaller at the top than at the bottom to allow for expansion due to the extreme heat. So when fitting a piston allow a clearance not more than .004 of an inch or less than .003 between the cylinder wall and the bottom or skirt of the piston. Pistons should all be as nearly as possible, of the same weight. The piston rings should be fitted between .003 and .008 of an inch when compressed. The circumference of the rings is smaller at the top edge than at the bottom which forms a taper and tends to keep the oil from working into the combustion chamber. The upper side of the rings are marked and care should be taken to keep this mark up. Also do not have the gaps in the rings in a line with one another.
“TAKING UP” BEARINGS In “taking up” a loose connecting rod bearing, the bearing cap is removed and the face filed. Care must be taken to file both sides of the cap evenly, or the bearing will wear on one side and cause the piston to knock. Just a little filing should be done and then the bearing cap put on and tested. With the bearing cap bolts drawn up as tightly as possible you should just be able to feel the bearing “seize” when turning over the motor with the crank.
VALVE TIMING The timing of the valves is an important operation but is not so complicated as generally supposed. The actual operation consists merely in checking the opening and closing of the valves in relation to the position of the pistons in the cylinders. This operation will automatically check the valve clearance which should be between .022 and .032 inches.
As the top of the push rods become worn it is impossible to check this clearance accurately on a motor which has been in use. For this reason it will not be necessary to check the clearance between the valves and push rods if the valves are properly timed with the piston travel.
In checking the gears, the mark “o” on the large cam shaft gear should fit opposite the tooth marked “Ford” on the small crank shaft gear.
To explain the timing of the opening and closing of the valves in relation to the position of the piston in the cylinder it will be necessary to understand what is meant by top and bottom dead center. “Top dead center” simply means the position of the piston when it is at the extreme top of its stroke. “Bottom dead center” is the lowest point in the stroke of the piston.
Let us consider the valve motion in the No. 1 cylinder. The exhaust valve should close at top center when the piston has just finished the exhaust stroke. The intake valve should open when the piston has traveled 1/16 of an inch downward on the intake stroke. In order to determine whether the exhaust valve is completely seated, in turning over the motor before the piston reaches top center, attempt to twist the valve head with the tips of the fingers. While the valve is open it will rotate freely but when it is seated it will not turn readily. Timing the valves in this manner will automatically cause the exhaust valve to open 5/16 of an inch before the piston reaches bottom center, and will cause the intake valve to close at 9/16 of an inch, after the piston has reached bottom center. It is very important that the valves be accurately timed according to this description, in order to have the valve motion in all four cylinders alike. This operation should be followed up with each cylinder.
SEE ILLUSTRATION NO. 9
The diagram shows the proper timing of the valves in a Ford Model T motor and the proper way to “mesh the timing gears.”
Illistration No. 9
FIRING ORDER In order to get full power from the engine there must be a combustion or power stroke in one of the cylinders for every 180 degrees of crankshaft rotation. To get this sequence of power strokes, according to the construction of the crankshaft, the firing order of the cylinders must be 1-2-4-3. Each valve is opened and closed once during four strokes of its respective piston or two complete revolutions of the crankshaft.
The foregoing explanation of the operation and construction of the engine has been given with the idea that the proper care of its mechanism cannot be taken unless it is understood exactly what the parts are made of and their purposes. With the various working parts of a motor its operation depends on five principal items, that is ignition, fuel, lubrication, compression and a cooling system. With these points considered, a gasoline motor will start and run. We will consider compression.
WHY COMPRESSION IS NECESSARY In order to compress the gases for the explosion and in order to receive the full impulse of the expansion, after ignition, it is necessary that the pistons and valves be air or gas tight. The condition of the compression in each cylinder can be determined by cranking over the motor with the ignition switch turned off. The resistance offered the crank handle through every half turn of the crank, indicates the amount of compression in each cylinder. For a “smooth running” motor, the compression in all the cylinders should be even.
The greatest destroyer of compression is carbon deposits which get under the valves and causes them to warp and the edges to become pitted. This is what necessitates the “grinding in” of the valves at frequent intervals. It is not advisable for the individual owner to attempt to do this work as it is such dirty work and requires special tools. As the Ford labor charge on this operation is so low, the driver would undoubtedly save expense by having it done at an authorized service station.
“OIL PUMPING” Another common trouble is the continual fouling of spark plugs due to what mechanics term “oil pumping.” Oil pumping is caused by worn or defective piston rings or undersized pistons which allow the cylinder oil to get into the combustion chamber.
It is poor policy to attempt to stop this trouble with so-called sure fire spark plugs. While it may seem to remedy it for the time being, still all this surplus oil is being burnt and forming carbon which will sooner or later cause more trouble. So the only remedy is to have new pistons or new piston rings fitted in the offending cylinders, which ever the case may require. However, if the precautions previously mentioned to avoid carbon deposits are heeded such as keeping the correct mixture in the carburetor, using good oil and gasoline, etc., the motor will operate for months at a time giving the maximum power with the minimum expense.
Below is a trouble chart which will help in determining the cause of various common “knocks” which occur in the motor. A chart of this sort must necessarily be of a very general nature. Only experience will enable the owner, driver or mechanic to distinguish the difference in the sounds of so-called “motor knocks.” However, the chart, if carefully considered will undoubtedly be of great assistance to the student. MOTOR KNOCKS CAUSE REMEDY
Sharp metallic click, noticeable on hills Carburetor mixture too “rich” or too “lean” Adjust carburetor Sharp metallic click, noticeable at all times, and all engine speeds. Carburetor mixture too “rich” or too “lean”
Overheating, due to: Water low in radiator. Oil low. Fan belt off.
Spark rod disconnected.
Oil feed pipe clogged. Adjust carburetor.
Check up, water, oil, belt, and spark rod.
After cooling, if motor still knocks take out front bolt in crank case plate. If oil does not gush out, feed pipe is clogged. Sharp tap at regular intervals. Valve clearance too great. Push rods or valves loose in guides. Have valves and checked up at. Service Station. Dull thud at regular intervals which can be traced to one cylinder by holding down vibrators on coils. Loose connecting rod bearing. Have bearing tightened at once or babbitt metal will be pounded out. Pronounced knocking noticeable when motor is idling or when running down hill. Piston slap, due to poorly fitting pistons high spots on pistons or bent connecting rods. Have attended to at once or cylinder bores will be worn out of true diameter. Pronounced heavy thud, noticeable on pull, which cannot be traced to one cylinder. Main bearing of crank shaft loose, also causes pistons to knock. Have crank shaft “rehung” at once or whole motor will have to be over-hauled. Pronounced metallic knock, noticeable when opening the throttle and on hills. Carbon deposits on cylinder head, pistons and valves. Clean Carbon and grind valves.
Lecture Number 6
PURPOSE OF THE TRANSMISSION The purpose of the transmission is to transmit the power from the motor to the drive shaft, to allow change of speeds and reverse direction, and to allow the motor to gain momentum before making it pull the load. The two principal types of transmission used for automobiles are the selective gear transmission and the planetary transmission.
THE FORD TRANSMISSION The Ford employs the planetary type. The use of the name planetary has grown out of the resemblance between the turning of three gears around a central shaft, and the revolving of the planets in their orbits around the sun. The planetary type of transmission is particularly adaptable to the unit power plant construction, as it is light and compact. It also avoids the possibility of stripping gear teeth as the teeth are in constant mesh.
PURPOSE OF THE CLUTCH An automobile clutch is a device which permits the motor to run independently of the motion of the car. It allows the transmitting of the power from the crank shaft to the drive shaft gradually, without jolts or jars. The two main types are the cone clutch and the multiple disc clutch. The Ford Car uses a multiple disc clutch running in oil for the high speed only.
For the reverse and low speeds, a band is tightened around the reverse and low speed drums respectively. The purpose of the low speed is to change the gear ratio, to permit the use of more power when first putting the car in motion and when climbing hills.
CONSTRUCTION OF THE TRANSMISSION The Transmission shaft with the drive plate and the universal joint is the connection in the line of power between the crankshaft, flywheel and drive shaft. One end of the transmission shaft is fastened to the flywheel and crankshaft by cap screws and dowel pins. The other end is piloted in the drive plate and is connected to it when high speed is engaged, through the multiple discs in the brake drum.
THE CLUTCH Keyed to the transmission shaft inside the brake drum, in the small disc drum which is grooved to receive the lugs on the inside circumference of twelve flat hardened steel discs slipped over it. These lugs key the twelve small discs to the clutch disc drum. Alternating between the twelve small discs are thirteen larger ones with notches on their outer circumference which fit: over lugs on the inner surface of the brake drum. These lugs key the large discs to the brake drum.
ACTION OF THE CLUTCH Against the last disc is the clutch push ring which has three lugs, projecting back through three holes in the face of the drive plate. Pressure is brought to bear on these lugs by the adjusting screws in the three clutch fingers which are hinged at the outer edge of the drive plate. The clutch shift collar bears against the inner ends of the clutch fingers. Pressure is applied to this collar by a heavy coil spring held in place by a cup-shaped spring support fastened to the drive plate sleeve.
The normal pressure exerted by this spring is 90 pounds but with the lever action of the clutch fingers it is raised to 324 pounds. Thus, when the emergency lever of the car is forward and the low speed or clutch pedal is allowed to come back into high, this releases the spring which causes its pressure of 324 pounds to be exerted on the lugs of the clutch ring through the finger adjusting screws. The pressure on the push ring causes the clutch discs to come together and complete the connection between the crankshaft and the drive shaft.
The fact that the discs run in oil makes them come together gradually, as the oil between them must be squeezed out before the engagement is positive.
We will now take up the action of the gears thru the high speed clutch, the low speed drum and the reverse drum.
SEE ILLUSTRATION NO. 10
Illistration No. 10
If illustration No. 10 is closely followed no difficulty will be experienced in tracing the lines of power. On the flywheel are located three sets of planetary triple spur gears. Each set of three gears is riveted together and revolves on three pins, pressed into the web of the flywheel 120 degrees apart.
ACTION OF THE TRIPLE GEARS The first gears, next to the flywheel, of each of the three sets, have 27 teeth and mesh with the central or driven gear, having 27 teeth also, which is keyed to the end of the brake drum sleeve, attached to the brake drum.
The second set of gears have 33 teeth and mesh with a central gear having 21 teeth out in to the end of the slow speed drum sleeve, which is attached to the slow speed drum and revolves around the brake drum sleeve.
The third set have 24 teeth and mesh with a central gear having 30 teeth, cut into the end of the reverse drum sleeve, which is attached to the reverse drum and revolves around the slow speed sleeve.
By having the three sets of triple gears, instead of one or two, the weight is more evenly balanced, the wear on any one set is reduced and consequently the gears are quieter.
ACTION OF THE GEARS IN LOW SPEED When the motor is started and forward motion is desired, the first the clutch pedal, the first pedal to the left, is pushed forward from the neutral position. This tightens the low speed band around the low speed drum and holds it stationary. Then as the low speed sleeve is attached to the low speed drum, the 21 tooth central gear is also held stationary and the 33 tooth gear meshed with it, is revolved around the 21 tooth gear by the moving flywheel. This will however, cause the 33 tooth gear to turn only 21/33 of a revolution on its own axis, or it will lose 12/33 of a revolution to the drive gear riveted to the low speed gear. Since the driven gear and the drive gear meshed with it both have 27 teeth, for every 12/33 of a turn the drive gear loses, the driven gear gains 12/33 of a turn. Thus when the clutch pedal is pushed forward with one turn of the flywheel the driven gear is turned ahead 12/33 of a revolution.
To make a complete revolution of the driven gear it will take as many turns of the flywheel as 12/33 is contained in 33/33 or 2-3/4 turns. Thus 2-3/4 turns of the flywheel will cause one forward revolution of the drive plate attached to the driven gear assembly. Then since the drive shaft makes 3-7/11 turns to the rear axles one, in low speed the ratio of the motor to the rear axle is 2-3/4 times 3-7/11 or the motor turns 10 times to the rear axles one, in low speed.
ACTION OF THE GEARS IN REVERSE When reverse direction is wanted the central pedal of the three is pushed forward. This tightens the band around the reverse drum holding stationary the 30 tooth gear fastened to it. In mesh with the 30 tooth central gear are the three 24 tooth gears of the triple gears. Thus when the motor is running and the flywheel makes one revolution, the 24 tooth gears in mesh with the 30 tooth gear will turn 6 teeth or 1/4 of a revolution more than a revolution. But in order for the car to stand still, the triple gears must make one revolution on their own axis while the flywheel is making one revolution. So if the 24 toothed triple gears make 1/4 turn more than a revolution while the flywheel is making one revolution then the 27 toothed drive gears will make 1-1/4 turns as well, and in so doing will force the central driven gear 1/4 revolution in the opposite direction. Thus if the 27 toothed central driven gear makes 1/4 of a revolution in reverse direction for one revolution of the flywheel it will make a complete revolution in reverse for four revolutions of the flywheel. Then since the ratio of the drive shaft to the rear axle is 3-7/11 to 1 the ratio of the motor to the rear axle in reverse will be 4 times 3-7/11 to 1 or 14-6/11 to 1.
ACTION OF THE GEARS IN NEUTRAL When neutral position is desired, that is with the motor running, and the car at a standstill, the clutch pedal is pushed forward into a position between high speed and low. By pushing forward the clutch pedal into this neutral position the clutch spring is pushed back so that it does not bear on the clutch fingers, thus the pressure on the discs is released and the small discs revolve independently of the large ones. Since the drums are free to revolve, the 27 toothed drive gears just mesh with the 27 toothed driven gears and in one revolution on the flywheel the triple gears make one revolution only on their own axis so the car stands still.
By pulling back the emergency or control lever, the clutch pedal is held in this neutral position.
THE FOOT BRAKE When it is desired to stop the forward motion of the car the clutch pedal is put in neutral position and then pressure is applied to the brake pedal, that is the right hand pedal of the three. This tightens a band around the brake drum, which being connected directly to the rear axle stops the car whenever the brake drum is held stationary.
Now that the operation of the transmission has been described, we will discuss a few precautions which will enable the driver to avoid transmission troubles.
CARE OF THE TRANSMISSION Do not let your motor run in neutral any longer than necessary as this tends to wear out the bushings between the transmission drum sleeves. It is very rarely that any trouble is experienced with the transmission gears, but if a grinding is detected, have it attended to at once and avoid a bigger repair bill later.
When the brake, low speed or reverse pedals are pushed forward, a band is tightened around each respective drum. These bands are lined with a heavy fabric about an eighth of an inch thick. These linings cause the bands to “take hold” gradually, quietly and without the friction that metal on metal would cause. But it is necessary to keep the bands adjusted properly to avoid their wearing out.
ADJUSTING THE TRANSMISSION BANDS They should be tight enough so that they take hold quickly and it is not necessary to push the pedals down to the floor boards, but loose enough so that they will not drag on the drums.
The low speed band is tightened by loosening the look nut on the right side of the transmission cover and turning the adjusting screw to the right. To tighten the reverse and brake pedal, remove the transmission case cover and turn the adjusting nuts on the shafts to the right.
Remember if the bands drag on the drums it will cause a loss of power and an overheated motor. Again let us advise that you keep clean oil in the crank case as this same oil also oils the transmission. Dirty oil causes the bands to deteriorate and also congeals on the clutch plates causing them to stick and the clutch to grab.
CARE OF THE TRANSMISSION BANDS If you attempt to reline the bands yourself be careful not to bend the bands out of their true diameter. Care must be taken not to drop tools, etc. into the crank case.
The rivets holding the band linings should be sunk deep into the lining, so that they will not come in contact with the drums.
In replacing the transmission cover great precaution must be taken that the gaskets fit properly to avoid oil leaks.
Learn how to save your bands. Do not apply your brake without first putting your clutch pedal in neutral.
LEARN HOW TO SAVE YOUR BANDS Use your throttle to slow down the car. Also by using your low speed pedal with the motor throttled you can save your brake band. When pressure is applied to the brake, apply it gradually and evenly, so as not to allow the band to slip. When coming down a steep hill, do not attempt to hold the car back with the brake. Use the low speed and let the compression of the motor hold you back.
When your bands commence to chatter or fail to hold after being repeatedly tightened, have them relined. Chattering bands are due to the surface of the fabric becoming glazed. This causes the band to take hold of the drum irregularly. Chattering bands are very injurious, not only to the transmission but to the entire car. The average driver gets only from three to six months wear out of his bands. But it has absolutely been proven that by using a little care and reason in the operation of your car, one set of bands will give you good service for a year or longer. Lecture Number 7
PURPOSE OF THE OILING SYSTEM The correct lubrication of an automobile means more to its perfect running order and long life than any other item of its care. There are at the present time, a great, many different types of oiling systems, most of them requiring force pumps and innumerable pipes or leads. Being more or less complicated they cause a proportionate amount of trouble. The problem to be met by any oiling system is to keep a thin film of oil between the moving, parts, preventing direct contact and thus avoiding undue friction.
THE FORD OILING SYSTEM The Ford model T motor uses the “constant level circulating splash system” of oiling. This system requires no pumps of any kind and the only pipe used is the one which carries oil thrown off the flywheel down to the timing gears/
PATH OF THE OIL The oil is poured into the crank case breather tube at the right and front of-the motor. From here it flows over the connecting rod troughs in crank vase lower cover, leaving them full, and then to the crank case reservoir or sump which is the lowest part of the crank case. When the motor is running, the flywheel and magneto magnets revolving in the oil in the reservoir, carry a portion of it up near the top of the transmission cover where it is thrown off into the funnel shaped end of the oil lead. From here it flows by gravity down onto the large timing gear, back again over the connecting rod troughs into the reservoir.
HOW THE PARTS ARE OILED The lower ends of the connecting rods dip into the troughs on every revolution, throwing oil on the cylinder walls, the main bearings, the cams and cam shaft bearings and in fact the constant splashing of the oil creates an of vapor which thoroughly lubricates all the moving parts of the engine.
There is a hole bored in the top of each main bearing bushing support so that the oil runs down onto the babbitt bearing surface.
SEE ILLUSTRATION NO. 11 The illustration shows the principle of the Ford constant level circulating splash system of oiling.
Illustration No. 11
There are two small holes which drain any oil which may work up between the push rods and push rod guides back into the crank case.
The transmission drums bands, sleeves, and gears are running in a constant bath of oil. The oil from the cam shaft gears also oils the generator drive gear. The starting motor drive gear and the bearings which support it are also lubricated by the oil in the crank case as the flywheel gear teeth which mesh with it, revolve in oil.
OIL LEVEL The Ford splash system has proven highly efficient for a great many years. It can readily be seen that it is very simple with no, parts to get out of order, or complicated leads to become clogged.
There are two pet cocks on the side of the crank case reservoir by means of which the oil level is tested. The best level is midway between these two pet cocks. If this level is maintained with a good high grade light oil which is renewed from time to time, no trouble will be experienced with improper lubrication.
CHANGE OIL OFTEN It is very important that the crank case oil be entirely drained out and renewed at least every thousand miles. The body of the oil becomes destroyed so that it loses its lubricating qualities. This breaking down of the body of the oil is caused by small amounts of gasoline vapor which leak past the pistons when combustion is not complete and by particles of carbon which are bound to get into the crank case from one source or another. Carbon forms on the under side of the pistons due to the extreme heat, this also gets into the oil.
To drain the crank case, unscrew the drain plug at the bottom of the flywheel casing and thoroughly drain off the old oil. Then replace the plug and pour in through the breather tube, a gallon of kerosene.
FLUSHING OUT THE CRANK CASE Run the motor for a minute or two. This will completely flush out the dirty oil and any old oil which may have congealed on the bearings etc. Again remove the drain plug and be certain that all the kerosene is drawn off. If any of the kerosene is left in the crank case it will thin out the new oil. The front end of the car should be run up a small incline or jacked up to drain out any kerosene which might be in the connecting rod troughs. Replace the drain plug and fill the crank case with one gallon of high grade light oil.
,center>OIL TESTS It might be well for every Ford driver to understand exactly what constitutes a good lubricating oil. We hear such expressions from time to time, as gravity test, flash test, viscosity, etc. and few people know what they actually mean.
GRAVITY TEST The GRAVITY TEST simply means testing the specific gravity of an oil with a hydrometer. However, when the lubricating properties of an oil are being considered, its gravity is of minor importance.
FLASH TEST The FLASH TEST simply means the determining of the flash point of an oil, or the lowest temperature at which the vapor arising from the oil when heated, will ignite without burning the oil, when a small flame is brought in contact with this vapor. The flash point should not fall below 400 degrees Fahrenheit as the extreme heat in the combustion chamber would otherwise cause too great a loss through vaporization.
COLOR The COLOR of an oil does not in any way indicate its quality or suitability for certain uses.
VISCOSITY TEST The VISCOSITY test determines the cohesive properties or consistency of the oil. There are instruments designed especially for the. measurement of the viscosity of oils. In the United States the Saybolt is most commonly used.
The viscosity is expressed by the number of seconds that it takes for a given volume of oil to flow through an opening of standard size, at a certain temperature. When we ask for light, medium or heavy oil we ask for oils of varying viscosities.
To get the most economical, fuel consumption and the best relative power, the lightest oil which will properly lubricate the motor, should be used. For example, an oil with a viscosity of 100 seconds would soon cause the pistons and bearings to “seize.”
Road and laboratory tests have proven that the highest economy of fuel and oil, with the best relative horsepower is developed by using an oil with a viscosity ranging between 300 and 800 seconds.
The viscosity of an oil varies with the temperature. For this reason a much lighter oil should be used in winter. A heavy oil will make it almost impossible to start a motor in below zero weather.
There are many other tests which oil can be subjected to, but the ones mentioned are probably the most important and will give the driver some idea of determining the qualities of oils.
Because the lubrication of the motor has been considered first, do not think that the filling of the grease cups, the oiling of the rear axle, universal joint, etc. are of secondary importance.
SEE ILLUSTRATION NO. 12
Illustration No. 12
Diagram No. 12 shows the location of all the oil cups, grease cups and other places which it is necessary to oil or grease from time to time. The oil caps on the front system, rear springs etc. should be filled frequently with any good lubricating oil. Cylinder oil is satisfactory.
OIL ALL CUPS FREQUENTLY On later model cars, the fan pulley bearing is oiled by removing a brass machine screw in the hub of the fan pulley. This bearing should be oiled every two or three weeks.
GREASE CUPS There are five grease or dope cups at various points on the chassis which it is very important to keep filled.
There is one small cup at the base of the steering column which should be filled every three or four weeks. Then on the universal ball cap joint to the rear of the transmission, is a large grease cup which oils the universal joint. This cup is often neglected with the result that the universal joint becomes completely worn out and must be replaced. This cup should be turned down to the right and taken off and filled with grease and replaced every week. There is no danger of getting too much grease in the universal joint.
Just to the rear of this cup is a smaller one which oils the drive shaft bearing. This should be filled every week as well. On the back of the rear axle housing near each wheel are two cups which supply grease to the axle roller bearings, these should be filled every week.
OILING THE REAR AXLE One of the most important items in the oiling of the car is the rear axle. At the right hand side of the center of the rear axle housing is a filler plug. This should be removed and the oil tested or the housing filled level with the hole*, every two or three months. A high grade heavy non-fluid gear oil should be used. This will keep the ring gear, the drive shaft pinion and the differential gears constantly running in oil and if carefully attended to, will prevent many a rear axle overhaul job.
* This level refers to 1919 and later axle housings where the filler hole was located below the centerline of the housing. On earlier axles, where the filler was on the centerline, the level should be kept at about an inch below the filler hole.
OILING THE SPRINGS Another part of the car which seldom receives attention is the springs. To avoid squeaky, noisy springs, and make an easy-riding car, try the following:
Mix a small can of graphite with one quart of cylinder oil. Soak a handful of waste thoroughly in this mixture and place it over the springs and under the channel cross members of the frame both front and rear, right and left. Poke it in firmly so it will not work out. With this method, each time the car goes over a bump a small quantity of the grease will be squeezed out and the leaves of the springs will be kept thoroughly oiled all the time.
GREASING THE FRONT WHEELS The front wheels should not be overlooked. Take off the front hub caps every two or three weeks, fill them with grease and screw back on. Then every two or three months remove the front wheels entirely, clean out the old grease off the roller bearings and the spindles and apply good fresh grease. This will prevent the wearing of the roller bearings.
The brake rods, both right-and left, should be greased` at frequent intervals where they rub against the brake rod guides. The hangers that support the hand brake lever yoke or controller shaft on each side, should have a few drops of oil now and then also.
OIL YOUR CAR AT REGULAR INTERVALS Get the habit of thoroughly checking up your car for oil and grease regularly. Test your cylinder oil every day. More danger can be caused by running without the proper amount of oil than anything else. Remember that dry metal against dry metal causes undue friction and wear. You cannot expect your Ford to give you good service unless you keep it properly oiled. Lecture Number 8
FRONT SYSTEM AND STEERING GEAR
DEVELOPMENT OF FRONT AXLES
It is very interesting to trace the development of axles and steering devices from those used by the first automobiles to the modern types. The original front axles were very similar to carriage o wagon axles. That is, the wheels revolved on spindles which were one with the axle bar itself and the axle was pivoted in the center. Thus to change the direction of the vehicle, the whole front axle was turned. To turn the axle just a simple vertical shaft and horizontal lever was used.
It was soon discovered that this system was entirely inadequate as every jolt or jar that the front wheels received was transmitted directly to the horizontal steering lever. This made it very difficult for the driver to hold direction on rough roads.
THE ACKERMAN PRINCIPLE Then the Ackerman axle was designed. Practically all front axles used on modern automobiles today are modifications of the original Ackerman principle. By this system the front axle remains rigidly attached to the frame or chassis thru the front springs. The wheels then revolve on spindles which are pivoted at each end of the axle proper. In this manner the desired direction of the wheels is obtained without moving the axle itself. Also much greater stability is obtained as the jolts which the wheels receive act thru a much shorter leverage.
Each spindle is controlled by a short lever arm and the lever arms are connected by a tie rod between them, so that when either the right or left lever or spindle arm is moved by the steering device, both wheels turn accordingly.
CONSTRUCTION OF THE FORD FRONT AXLE The Ford front axle is a drop forging of Ford vanadium AA steel. It is of “I” beam construction, light in weight but very tough. It is capable of withstanding terrific shocks without breaking.
When the axles are bent they should be straightened cold as heating will draw the temper from the steel. The steel in the axle is put thru two different heat treatments and annealed at 1020 Fahrenheit. Its final tensile strength is 125,000 to 145,000 pounds per square inch.
THE SPINDLES The spindles are the axles on which the wheels revolve. The spindle assembly consists of the spindle itself, the spindle arm, the inner cone, the outer cone, the steel washer and a “hex” castellated nut. The spindle assembly is set in bosses which are forged in one with the main axle, a hardened steel bolt being the pivot on which the spindle turns. There are bronze bushings pressed into the top and bottom of the spindle body which form the bearing surface. They are oiled by a hole drilled in the top of the spindle bolt.
The right spindle has a left-hand thread and the left spindle has a right-hand thread. This is to prevent the friction of the hubs from loosening the outer cones, and thus binding the bearings in their races. The spindle arms fit into the holes provided in the spindle bodies and are held rigid by a hex castellated nut. The other end of the arm is bored to receive the spindle arm bushing.
The tie rod or spindle arm connecting rod with a yoke at both ends, fastens the spindle arms together so that the wheels turn in unison. The right hand yoke is threaded on to the tie rod in order to adjust the alignment of the wheels. The spindle arm connecting rod is connected to the ball arm at the base of the steering column by the steering gear connecting rod. There is a ball socket at each end of this rod which connects with the spindle connecting rod ball on one end and the steering arm ball on the other.
THE FRONT WHEELS The Ford wheels are wooden for strength and lightness. The spokes on the front wheels are “dished” or shaped like a flattened cone to better withstand shocks. This also brings the weight supported by the spokes on a straight line, as the front wheels are set at an angle of three degrees to vertical. This angle is obtained by the spindle being forged at an angle to the spindle body. This makes the steering of the car much easier as it brings the point of contact of the wheels nearer in line with the pivot on which the spindle turns.
SEE ILLUSTRATION NO. 13
Illustration No. 13
The diagram shows the front system in detail. This outward flare of the wheels at the top is known as the “camber.” In order to counteract the tendency of the wheels to turn out away from each other, due to the camber, it is necessary when aligning the front wheels to “toe them in” from one eighth to one quarter of an inch. This “toeing in” of the wheels is called the “gather.” The front axle is tilted bank five and one half degrees to obtain a “castor” effect. This also tends to make steering easier, and causes the car to hold the road. The axle is held at this angle thru the front spring and the spring perches on the upper side, and the radius rod on the lower side.
THE RADIUS ROD The radius rod is a V-shaped support constructed of hollow steel tubing. It is light and strong, but when bent no attempt should be made to straighten it as it will be weak in the former bend.
The radius rod is fastened at the rear to the crank case by a ball and socket joint. The two front ends are fastened to the lower side of the axle by nuts over the end of the spring perches.
TREAD, WHEELBASE, CLEARANCE The tread, or the distance between the ground contact of the wheelson opposite sides of the car is 66 inches. The wheel base or the distance from the center of the front hubs to the center of the rear hubs is 100 inches. The clearance or the distance from the lowest part of the car to the ground is about ten inches.
THE FRONT SPRING The Ford front spring is a type known as semi-elliptic transverse. It is built up of seven laminations or leaves. The first or main leaf being rolled at the ends, to form the “eye” by means of which the spring is fastened to the perches. The remaining leaves are graduated in size to the seventh or top leaf which is the smallest. There is a tie bolt which runs thru the center of the spring. The assembled spring is fastened to the front cross member of the frame by the spring clips.
Care should be taken to keep the spring clips tight or the tie bolt might become sheared and the body would shift to one side. On each spring are two rebound clips which hold the leaves in alignment on a rebound and cause the spring to act as a unit rather than throwing the strain on the main leaf.
The leaves are given a special heat treatment, shaped in a special bending machine and cooled in oil. The temper is then drawn in sodium nitrate. Each spring is thoroughly tested before it is finally passed.
THE STEERING ASSEMBLY The steering device by means of which the action of the steering wheel is directly transmitted to the front system consists of the steering column housing which is bolted to the dash by a bracket. The steering gear post is the long steel shaft which transmits the action of the wheel. At its lower end is keyed with a Woodruff key, the steering gear ball arm. At the upper end is a triangular piece of steel bearing in each angle, dowel pins, which are the axis of three twelve toothed gears. These gears mesh on the outer side with the 36 teeth on the inner surface of the stationary shell which is fastened to the top of the steering column shaft housing. The three gears mesh in the center with the steering gear drive pinion which also has twelve teeth. The steering gear cover is threaded into the shell and the steering wheel is keyed to the upper end of the steering gear drive pinion. Thus when the steering wheel is turned, the motion is transmitted thru the steering gear drive pinion to the three steering gear pinions which being mounted on the triangular end of the ‘steering gear post cause it to revolve and in turn transmit the motion to the steering gear ball arm.
This is known as the semi-reversible type of steering gear. Since the Ford car is so light, it does not require a large gear reduction and is consequently much simpler than the larger cars.
The entire Ford steering gear and front system is constructed of the very best of steel. Each part being built of a grade of metal particularly designed for its purpose. Since the lives of the occupants of the car depend upon the ability of the steering mechanism to receive severe shocks, and to respond quickly in cases of emergency, the steel used must be tough rather than extremely hard, so that the parts will not crystallize and snap off.
CARE OF THE FRONT SYSTEM Now that the manufacturer has done his part to construct a safe and efficient front axle and steering gear, it is only fair to demand that the driver take care of it and keep it in proper working order.
In the first place the front wheels must be absolutely true. It is foolish to attempt to line up wheels that are untrue. In nine cases out of ten the wheels that appear to be untrue simply have rims on which the rim lugs have not been tightened evenly and the tire gives the wheel a wobbly appearance.
To determine if the wheel itself is out of true, jack up the front axle and hold a piece of chalk steadily but lightly against the outside edge of the felloe or the rim into which the outer ends of the spokes fit, and spin the wheel. If the chalk marks the felloe for a complete revolution, the wheel is true; if not, the nearest service station will undoubtedly have bending blocks for straightening wheels.
TO ALIGN THE WHEELS Assuming that the wheels are true, to align them, the following is a good practical method. Turn the wheels so that they point directly ahead between the spokes of one wheel and with a long straight stick or rod, across under the radius rod to the other wheel, measure the distance from the inside edge of the felloe of the far wheel to the outside edge of the felloe of the near wheel. Holding this measurement on the stick or rod measure the front of the wheels in a corresponding position, on the felloes that is directly opposite on the circumference of the wheel, to where the first measurement was taken. This last measurement or front measurement should be one-eighth to one-quarter of an inch shorter than the first measurement or the one taken to the rear of the wheels. If the measurements do not check up in this manner, take out the spindle arm bolt from the spindle arm and yoke and turn the spindle arm connecting rod either in or out on the threads as the case may demand, until the proper measurement is obtained.
BE SURE YOUR FRONT WHEELS ARE ALIGNED AT ALL TIMES. It will make steering easier, prevent the racking of the front system and save the tires. Driving with the front wheels out of alignment will completely ruin a set of new tires in a few miles.
LOOSE FRONT SYSTEM Another trouble which can be overcome by giving proper attention to the front system, is a violent trembling or shaking of the front wheels after hitting a bump; which is carried on up the steering post and tends to shake the wheel out of the driver’s hands. This can always be traced to the following: loose spindle body bushings or loose spindle bolts, loose spindle arm bushings, or loose spindle arm bolts, loose ball cap joints on the steering post ball arm, or the connecting rod yoke ball or the front axle is not tipped back at the proper angle or the radius rod is not securely fastened.
Keep the spindle bolts and the spindle arm bolts up snug at all times but not tight enough to bind. The spindle body and spindle arm bushings need to be replaced after continued wearing. To determine if the looseness is in the bushings jack up the front axle and attempt to shake the wheel with both hands, if the wheel is tight on the spindle and still there is play, it is probably in the bushings.
The ball caps should also be drawn up snug. If the ball and cap has become so worn that it will not draw up closely, a little filing on the face of the cap will fix it. Keep the front system tight all around and the axle tipped at the correct angle and the trembling trouble will not be experienced. Keep the spindle bolts and ball naps oiled and they will give longer service without adjustment or replacement.
The steering gear itself seldom causes any trouble. The triple gears. in the shell at the top of the post should be greased about every five thousand miles. Sometimes a cracking noise is heard in the steering column, when the car is being maneuvered; this is usually due to the steering gear ball arm not being driven firmly on the tapered end of the steering gear post and the retaining nut drawn up tightly. The steering post bracket bolts thru the dash should also be kept tight.
DO NOT NEGLECT THE FRONT SYSTEM TOO MUCH DEPENDS ON THE PROPER ACTION OF THE FRONT SYSTEM, TO NEGLECT IT. It is better to keep the car in good repair than to have an accident and regret the shiftlessness afterwards. Buckled radius rods rarely occur thru defective parts, but rather on account of loose connections or misalignments. Is it worth while to neglect your Ford? Lecture Number 9
REAR AXLE ASSEMBLY
TYPES OF REAR AXLES
The development in the design of automobile rear axle has been quite as interesting and vital to the modern car as any other unit of its construction. There are two types of rear axles used at the present time, namely “dead axles” and “live axles.” By a dead axle is meant an axle so designed that the axle shaft itself, remains stationary, with the wheels revolving on the axle ends. This design usually makes it necessary to drive the wheels with sprockets and chains. Particularly with pleasure cars, chain drives have caused trouble and noise so the “live axle” or floating axle was the natural result.
Live axles are axles to which the wheels are directly fastened. They revolve in housings and the motive power is transmitted to them by means of a drive shaft from the motor to drive gears in the axle. “Live axles” are designated as “plain live axles,” “semi-floating,” “three-quarter floating” and “full floating according to the manner in which the .axle shafts take the bending and torque stresses.
THE FORD REAR AXLE The Ford axle is a “plain live axle.” The rear axle assembly consists of the universal joint and housing, drive shaft and housing, differential assembly, rear axle housing, axle shafts, hubs, brake shoe assemblies and rear radius rods.
THE UNIVERSAL JOINT The universal joint is the coupling between the trans-mission and the drive shaft. It allows the drive shaft to rotate at an angle to the crankshaft which is necessary on account of the differential and driving gears in the rear axle being lower than the crank shaft.
The universal joint is built up of a male and female knuckle joint of case hardened steel, assembled between two rings which are riveted together. The Ford universal joint will allow an angle of 45 degrees, however the actual angle of the drive shaft to the crank shaft is about 25 degrees.
The square end of the. male knuckle joint fits into a square hole in the transmission drive plate. The female knuckle joint fits over the square end of the drive shaft and is held by a quarter inch pin, which is riveted. The upper end of the drive shaft housing is a ball joint which serves as a housing for the universal joint and permits the turning and twisting of the drive shaft and housing over, uneven road conditions.
THE DRIVE SHAFT The drive shaft is the link in the power line between the universal joint and the differential gears of the rear axle. It is 1.062 to 1.063 inches in diameter and 53-5/8 to`53-3/4 inches long. The upper end is square to fit the square hole in the,; universal knuckle joint. The lower end is tapered and has keyed to it, the drive shaft pinion gear.
DRIVE SHAFT BEARINGS The drive shaft is supported by three bearings. Directly back of the universal joint is a babbitt bearing, one end of which is flanged to help prevent end play in the drive shaft. This babbitt bearing is the support for the forward end of the drive shaft.
Just forward of the drive shaft pinion gear, at the rear end of the drive shaft, is a Hyatt roller bearing. Then just forward of the roller bearing, is a ball thrust bearing which takes care of the tendency of the drive shaft to thrust forward due to the fact that the drive shaft pinion and the differential drive gear are bevel type gears. This ball bearing does not form a bearing surface for the shaft to run on but prevents friction caused by this forward thrust of the drive shaft. This bearing rests against the flange in the drive shaft tubing.
THE DIFFERENTIAL ASSEMBLY The next link in the line of power is the DIFFERENTIAL ASSEMBLY. The purpose of the differential as was previously stated, is to permit the rotating of one rear wheel at a different speed from the other. Also the second change in direction in the line of power is effected thru the drive shaft pinion gear and the bevel ring gear which is fastened to the differential case.
The differential assembly is composed of the right and left half of the differential case, the spider with three arms, three differential pinion gears and the two differential gears which are keyed on to the inner ends of the axle shafts; the rear axle being constructed in two sections. The gears are keyed on to the shafts and also looked with a look ring which prevents the gears from coming off when the wheels are tightened on the other end of the shafts.
ASSEMBLING THE DIFFERENTIAL To assemble the differential after the two gears are keyed on the axle shafts, first the three differential pinions are placed on the arms of the spider, then the spider is placed over the end of one shaft and the other shaft fits in the remaining half of the hole in the spider. A fiber washer one thirty-second of an inch thick is placed between the two inner ends of the axle shafts to prevent noise.
The other half of the differential case is next placed over the gear on the second axle shaft, the two differential gears are meshed with the three pinions and the two halves of the case are bolted together. Then the large ring gear is bolted to the left half of the differential case.
The action of the differential is simply this, that when the resistance offered by the back wheels is the same the differential pinion gears remain stationary and the whole differential revolves as a unit. However, when the resistance offered the back wheels is not the same, for example when the car is turning a corner, the pinions will not only revolve around the studs on the spindle but at the same time will run around the gears on the axle shaft. Thus if the resistance is uneven on the back wheels, the large ring gear will rotate forward with the wheel offering the least resistance. The differential pinions during this time turning on their own studs, and running over the surface of the gear, which tends to remain stationary.
REAR AXLE HOUSING The REAR AXLE HOUSING is in two sections, the inner ends of the halves being bell-shaped to house the differential Assembly and the outer ends flanged. Inside the housing are four Hyatt roller bearings which supply the bearing surface for the axle shafts. Two of the bearings are located in the center and the other two close to the outer ends of the shafts.
CONSTRUCTION OF ROLLER BEARINGS The bearings are carried in hardened steel sleeves. The purpose of the bearings is to reduce friction. All the roller bearings used on a Ford car are high grade Chrome nickel steel. The rollers are held in the races by the “cage” which is a flat ring at each end of the rollers fastened together by bars. According to the duty which the bearings have to perform the races are made of different grades of steel. The rollers are made with “spiral runs” in them and then are set in the “cage” so that these “runs” go in the opposite direction on every other roller. This tends to carry the oil across the bearings and keep them thoroughly lubricated.
REARWHEELS LOCKED TO SHAFTS The wheels are fastened on to the tapered ends of the axle shafts and looked with a key. They are drawn up tight with a “hex” castellated nut, locked with a cotter key. It is important to keep the rear wheels drawn up firmly at all times or there will be a play in the hubs which might cause serious trouble.
THE EMERGENCY BRAKE The rear wheel hubs carry the pressed steel brake drums which house the emergency brake shoes and their operating cams which are assembled to the flanges of the axle housings. The EMERGENCY BRAKE ASSEMBLY in each rear wheel consists of a pair of semi-circular cast iron shoes pivoted at one end and held against an expanding cam by coil springs at the other. These cams are connected to the brake rods and then to the hand lever. Thus, when the hand lever is pulled way back it tips the cams, spreading the brake shoes apart and against the inside circumference of the brake drum.
The emergency brake should be used mainly for holding the car still when starting the motor or to hold the car in place when stopped on hills, etc.
THE REAR SPRING The whole rear axle assembly is held in plane by the rear spring and the rear radius rod. The rear spring is similar to the front one in design being also “semi-elliptic transverse.” It is bolted to the cross member of the frame in-the center and each end is fastened to the perches which are bolted to the rear axle housing flanges.
THE REAR RADIUS RODS The rear radius rods hold the rear axle at a right angle to the drive shaft. They are constructed of hollow steel tubing bolted at the rear ends to the flanges of the axle housing and at the forward ends to the drive shaft housing. Like the front radius rods it is impractical to attempt to straighten the rear radius rods when they are bent to any considerable degree. They will usually be weak and will tend to snap off, from vibration.
Illustration No. 14
Illustration 14 shows the construction of the rear axle assembly.
CARE OF THE REAR AXLE The rear axle will not give trouble if it is properly taken care of. In the first place the housing must never be allowed to run dry of oil. Nothing will cause gears to wear more quickly than to permit them to become dry.
In the winter time the grease or oil is apt to become hard so that the gears will out a track and then receive no benefit from the oil. This can be avoided by putting in the housing about a pint of cylinder oil which will mix in the other non-fluid oil and form a better lubricant.
It is a good plan to put a little grease on the emergency brake cams to prevent them from sticking. Also the two grease cups which lubricate the two outer roller bearings must be kept filled at all times.
Then all the various parts of the assembly must be kept tight. Such as the drive shaft ball housing, the radius rods and particularly the rear wheels must be drawn up on the axle shafts so that there is absolutely no play. Occasionally the keys in the rear hubs will become loose from vibration and particularly from chattering due to defective bands. Loose hubs will wear out the key in the hub and the axle shaft as well and might cause the keys to snap off sometime when the brake is suddenly applied, as the whole weight and momentum of the car is against them. It is not necessary to put grease in the rear axle hub caps as there are no bearings at these points.
NOISY GEARS When an axle first becomes noisy, that is the time to have it fixed before more serious trouble develops. End play in the drive shaft caused by defective or worn bearings will cause a growling noise in the rear axle when the car is going down hill under its own momentum. End play will cause the pinion gear on the drive shaft to mesh in too far with the bevel ring gear and will wear out the gears if not remedied.
When it is necessary to replace parts in the rear axle it is important to inspect the teeth of the ring and pinion gear. If the “pitch” or face of the teeth is worn it is advisable to replace both gears. When an attempt is made to mesh new gears with old ones a growling noise will result. It is much wiser to have the parts replaced while the axle is dismantled than to assemble the axle with some worn parts and in two or three weeks have a reoccurrence of axle trouble which will make it necessary to pay for the same shop operation.
ADJUSTMENT OF THE BRAKE RODS Check up the adjustment of the brake rods so that the neutral position of the hand lever will be when the lever is straight up and down and still will not drag the brake shoes on the emergency brake drums. However, the emergency brake should commence to work as soon as the hand lever is pulled back of this vertical position.
THE TRUCK REAR AXLE The axle of the ton truck is the same in design as the pleasure car axle. That is, it is a plain live axle. However instead of having four roller bearings to support the axle shafts, the two inner bearings on either side of the differential are ball bearings and the outer ones are roller bearings.
The driving gears are the worm and worm gear type instead of the bevel gear type, as used in the model T chassis. That is, there is a worm on the end of the drive shaft, instead of a pinion gear, which meshes with a large worm drive gear.
Too much stress can not be laid on the oiling of the truck rear axle. A heavy fluid or semi-fluid oil should be used. Keep the housing full up to the upper oil plug at all times. The truck rear axle housing is provided with a drain plug on the lower side so that the oil may be drained off and renewed, particularly with a new truck it is a good plan to change the oil after the first 500 miles. Care must also be taken to keep the grease cups which oil the roller bearings full and turned-up. Lecture Number 10
TIRE CARE, ROAD LAWS & GENERAL REVIEW
PURPOSE OF PNEUMATIC TIRES
The reason for using rubber tires on all modern autoobiles is to overcome shocks and vibration. If it were not for the tires, the machine, with its delicate construction, would soon be racked to pieces. Slow-moving vehicles such as “electrics” and trucks find hard tires adequate to absorb the vibrations. But high speed cars require the air cushion furnished by the pneumatic tire and in later years it has been proven that pneumatic tires are more practical even for the heavy slow-moving vehicles.
The form of pneumatic tire most commonly used is the double tube tire mounted on a demountable rim. With this method a spare tire can be carried inflated and ready for use in case of punctures or blow-outs.
IMPORTANT ITEMS IN THE CARE OF TIRES The development in tire manufacturing has been so rapid and competition has been so keen that there are today any number of very good tires on the market. However, there is no tire which will give the long service of which it is capable unless it is given the proper care.
In the first place more than three-fourths of all tire trouble is due to under inflation. The weight of the car on a soft tire causes the rubber tread to loosen from the fabric and crack, which makes the weak spots causing blow-outs. It is easy to understand that a tire inflated to the proper amount will present less wearing surface to the road and will consequently give longer wear. For this reason, it is important to check up the pressure in your tires with an air gauge at regular intervals and keep them inflated to the pressure designated by the tire manufacturer. A common rule is to inflate a tire about eighteen pounds for every inch in diameter. However about sixty-five pounds for the 30 x 3-1/2 tire will be very nearly correct for most makes.
Never drive with a flat tire even a very short distance. It will cut the tube all to shreds and ruin the casing as well. It is better to drive slowly and carefully on the rim. Do not drive with wheels out of alignment. New tires can be completely destroyed by driving a car with the wheels out of “line” to any extent. Also see that the wheels are true and the rims drawn up straight on the wheels.
As far as possible keep grease and oil from getting in contact with your tires as oil is very injurious to rubber. Avoid skidding, running in car tracks and ruts, or bumping the wheels against the curbing. These things all tend to shorten the life of your tires. Also do not set your brake suddenly enough to cause your tires to drag on the road.
Another point which very often is not considered, is the importance of using tires of the same diameter on the rear wheels and if chains are used apply them to both wheels.
USE TIRES OF THE SAME SIZE ON THE REAR WHEELS If the diameter, or traction of the rear wheels is not the same, it causes the differential to be in action all the time the car is in motion. This means a loss of power and an unnecessary amount of wear on the differential parts.
If these few precautions are heeded a great difference will be noticed in the tire mileage obtained.
ROAD LAWS: BE FAMILIAR WITH TRAFFIC REGULATIONS It would be impractical in these lectures to attempt to “lay down” any specific number of road laws which should be adhered to, as the laws in various states differ and also each city of any size has it’s own local traffic rules. However, we do advise that every person driving a car send to the secretary of state for a copy of their state laws, and to their city traffic superintendent for a copy of the city traffic regulations. Familiarize yourself with these laws and you will undoubtedly save yourself considerable embarrassment and inconvenience.
BE REASONABLE In general “play safe” at all times. In approaching “blind” curves or crossings do not take the chance that there will be no one there but drive your car at a speed that will permit you to stop quickly if necessary. Consider the “other fellow”; do not use your “spot light” but use your “dimmers” and SHARE THE ROAD when you are passing cars on narrow highways. Many an accident has been caused by a “smart” or “trick” driver crowding an inexperienced driver off the road.
GENERAL REVIEW The following list of questions does not cover the entire substance of the lectures but is a suggestive list of the most vital points.
QUESTIONS LECTURE NO. 1
1. What is a chassis?
2. Explain the thermo-syphon system?
3. How much water should be kept in the radiator?
4. What is the best method to prevent the radiator from freezing?
5. Explain a practical method for starting a Ford car in cold weather.
LECTURE NO. 2
1. What are the sources of electrical current for ignition?
2. Explain the purpose and care of the timer.
3. Trace the current from the magneto to the spark plugs.
4. How are the coil units adjusted?
5. What should the “gap” be in the spark plugs? How are they adjusted and cleaned?
LECTURE NO. 3
1. What type of fuel supply is used on the Ford car?
2. What is the location, purpose and care of the sediment bulb?
3. What is the purpose of the carburetor? How is it adjusted?
4. Why does pulling out the choke lever help start a cold motor?
5. Explain how gasoline may be saved on long trips.
LECTURE NO. 4
1. Name the principle parts of the Ford starting and lighting system and their location.
2. How should the ammeter register at various speeds?
3. What action should be taken if the ammeter shows a disoharge?
4. How would you determine if the Bendix drive was “looked” and how free it?
5. What care should be given a storage battery?
LECTURE NO. 5
1. What is meant by a “four cycle internal combustion engine”?
2. Explain what takes place during the four “strokes” or “cycles.”
3. What is a practical method of timing the valves?
4. What are the five principle items necessary for the operation of the motor?
5. What are some of the reasons for motor mocks and why should they be eliminated at once?
LECTURE NO. 6
1. What is the purpose of the transmission?
2. What is the purpose of the transmission bands?
3. What action should be taken if the car “chatters” when the foot pedals are applied?
4. How are the transmission bands adjusted?
5. How is unnecessary wear of the transmission bands prevented?
LECTURE NO. 7
1. What type of oiling system does the Ford car use?
2. What is the proper oil level and how often should the oil be changed?
3. How do you determine when the oil feed pipe is clogged up?
4. Explain the method of draining and flushing out the crank case.
5. Name the location of the grease cups and all other important points to oil and grease.
LECTURE NO. 8
1. What care should be given the front springs?
2. Explain method to use in “lining up” front wheels.
3. What is meant by castor, gather, and camber?
4. What should be done when the spindle bolts, spindle arms, and ball cap joints become loose? What will prolong the life of these parts?
5. What causes cracking noise on the steering post?
LECTURE NO. 9
1. What type of rear axle does the Ford car employ?
2. What is the purpose of the universal joint?
3. How do you determine “end play” in the drive shaft? What causes it?
4. What parts should be watched for looseness and kept tight?
5. What is the main purpose of the emergency brake and how is it adjusted?
LECTURE NO. 10
1. What is the purpose of pneumatic tires?
2. Explain the importance of keeping the tires inflated to proper pressure.
3. Why should the traction be the same on both rear wheels?