Still working on the 1927 engine. I think I have the timing correct running a distributor, but when started the ammeter shows discharge and the battery loses it's charge and won't start the car again until I put on the charger. The switch is a modern repo. and it's junk, could that be causing the problem or do I have something else driving me crazy--er. Maybe the generator? Harv.
Does the battery discharge when the engine is not running? If so, something in a circuit is grounded which should not be grounded. The most common would be the cutout on the generator being stuck or shorted, causing the battery to discharge through the generator. If it does not discharge when the ignition is off, something else would be the cause.
To start with, the battery should be negative ground. The positive terminal is connected to the starter switch. The other terminal on the starter switch would be connected to the starter. Everything else in the car is connected to the starter switch on the same side as the battery. If you have a stoplight, it might be connected at the starter switch, or maybe not. Since the stoplight is not part of the original wiring, it will not be on the diagrams in the book. There is a yellow wire going from the starter switch to the terminal block on the firewall. Another yellow wire goes to the ammeter and a yellow with black tracer goes from the opposite side of the ammeter to the terminal block. A wire from the terminal block yellow with black tracer is connected to the generator cutout. The cutout is either of three kinds. The original equipment is a relay which operates when the generator starts to charge. That relay connects the generator output through the yellow with black tracer to the terminal block and the ammeter. When the generator is charging, the ammeter should read +. Another type of cutout is a diode. The diode will allow the current to pass from the generator toward the battery, but not from the battery toward the generator. If you have a diode, and the battery is connected backward, that is with a positive ground, the cutout would allow the current to go from the battery to the generator and discharge the battery through the generator. However that would happen even if the engine is not running. The other type is a voltage regulator. With a voltage regulator, the battery would have a high charging rate if the battery is low but if it is fully charged the ammeter would show a very small charge. The lights are connected to the side of the ammeter which has the yellow with black tracer. That will lower the needle on ammeter when the lights are on. It might even read discharge. The ignition switch is also connected to the yellow with black tracer. So when the ignition is connected to battery, it would show a discharge if the engine is not running, but a charge when the engine is running. A distributor would be connected through the ignition switch to battery. If the ignition switch is on and the engine is not running, you would have a discharge when the points are closed, but no effect on the battery when the points are opened. With the engine running, the points would be closed for such a short time each stroke, that the ammeter would still read +.
Anyway, I think you might have a problem with the generator, or the cutout.
You need to follow all the circuits and see if there is anything grounded which would cause the battery to discharge.
It would help us distant trouble shooters if you would tell whether it discharges only when running or when not running.
I have seen wiring diagrams posted on the forum, so you could do a search, or maybe some other poster will post the diagram.
Thanks Norman, I never thought about the generator cutout being stuck. It does seem to discharge when not running, battery seems to die very fast. I have checked and double checked all possible ground faults and can find no ground problems with wiring. The ammeter seems to show discharge only so I believe The generator or cutout is the problem. Is there a way to check or troubleshoot the generator for proper operation? and is anyone doing quality rebuilds on generators that you know of? Harv.
Check the screw terminal on the cutout. Be sure the screw is not too long or it will ground to the generator yoke (case).
Check the voltage from the generator post to ground. It should be zero with the engine off. If it reads any voltage, the cutout points are stuck closed. It's probably burned the tickler circuit too which makes the cutout a paper weight.
Disconnect the lead to the cutout and protect it from grounding. (Engine OFF) Check the ammeter and see if it reads zero. If it reads zero, the cutout is toast. If it still reads a discharge, you have a short somewhere between the generator wire and the battery.
Verify that the meter zeros when the battery is disconnected. If it still shows a discharge, the meter is bad.
(Message edited by ccwken on February 15, 2015)
Not sure why I called that the "tickler circuit". It's the primary cutout coil winding. The one that draws the points closed.
The "generator post" in the second paragraph is the large post from the generator with the nut. Not the battery side of the cutout.
One other thing I can think of which would also cause the battery to discharge would be the screws on the terminal block. The 27 has a steel firewall and sometimes one or more of the screws in the terminal block is too long and will make contact with the firewall. That would ground whichever circuit is connected to that screw.
Thanks all I'll go through all those checks today and let you know what I find. I just noticed that my fingers must have been tired when typing the header. Harv
With all your help I think we have isolated the problem, With key off ammeter shows charge, key on slightly more charge, engine running discharge.
The cutout is a Delco Remy. With engine off and cutout lead disconnected ammeter reads zero. With engine off generator post to ground has voltage, also voltage from green distributor to coil wire and cutout. Harv
Harvey, your ammeter is wired backwards. If you are testing the post on the generator, you will have continuity and the same for the green wire to the distributor if the points are closed. With the key off you should get no reading on the wire coming from the cutout.
It would be more than the ammeter wired backward if the battery is actually discharging. I could be wrong, but check to see that the positive pole from the battery goes to the starter switch. If the battery were backward, the ammeter would read backward, but it would still charge the battery.
It could also be that you have a bad battery. How old is the battery? and did it sit in a discharged condition for a long time?
I think I got that backward. If the battery were connected wrong it would discharge the battery.
That's not entirely correct. The tests I gave him were NOT continuity test but voltage tests. The yellow/black wire to the cutout is always hot. The generator post to ground should only show voltage when the engine is running. If it shows voltage when the engine is off, the cutout is stuck.
Ditto on the backwards wired ammeter.
You are all amazing, Yes the ammeter was wired backwards. I fixed that problem and still have a hot wire from the generator when ignition is off. Must be the cutout. I'll order one on Tuesday from Lang along with some other stuff. Lang's has a cutout with a diode to eliminate the possibility of sticking points. I am still having a problem with timing on this unit, it seems to run better when spark is retarded. The instructions on the Texas T distributor says to rotate the head clockwise until points begin to open for #1 firing position. But doesn't the distributor rotate counter clockwise. Those instructions seem backwards to me. Any help?
Do yourself a favor and order the voltage regulator from Fun Projects. It looks just like the cutout but is an actual voltage regulator and not just a switch like the original cutout. The cutout (and the diode) just keep the battery from back feeding the generator when the engine is not running. A cutout will charge the battery even if it does not need charging and reduce battery life.
I'll order a regulator Tuesday. Any help with my timing issue? Harv
A T will run quite well on a distributor but I quit using them on my T's over 20 years ago. I am sure that someone else can help with that question.
Harvey, I have a old Bosch distributor on my 25 TT. Just pull the cap and hand crank the motor watching which way the rotor moves. Then come around to #1 on compression TDC. Bring the piston about 1/16" down past TDC. Now rotate the distributor until the points just open and lock it down. Be sure the spark lever is all the way up. PK
Thanks Pat I'll give that a try. Harv