I have read recent postings concerning Etimers.
I do not have the option of using my stock system on mag as it only functions on bat position.
The car runs well in this arrangement.
My point is if one gets a spark which ignites the fuel at the right time then how does in matter where the source is ? How does the quality of the spark affect the bang for your buck.
Apologies in advance for my simple brain!!
Still Learning about T s!!
The only concern would be is you say your mag is inoperative. If it were mine I personally would tear the engine down to find the problem. I do not care what ign. system anyone uses in their T though I try to stay close to stock. The concern is using any other device to overcome a problem that may become much worse without a look see and may be catostropic in nature. In my opinion at that point of tear down it will cost little more to preserve the stock ignition. Many will not agree, sorry bout dat. KB
If you are running on a 12V battery, then your performance should be as good as the mag or E-Timer. If you are running a 6V battery then you will have a little less power up to 35mph then more power loss above 35mph. Many T's have been ran that way for years.
Regarding 6V power, "The Model T coil has a fixed operate time based on any given voltage and the crankshaft has a variable rate of speed based on RPM. Basically what happens is, the crankshaft outruns the coils ability to keep up and ignition timing becomes severely retarded at higher RPM." by Ron Patterson.
Here is the whole story:
And the differences in power output at:
The retardation theory is part of the problem, but not the real culprit. The main reason for the poor performance on 6 volts with timer and coils is the likely inter-cylinder timing disparity. This disparity is a linear function tied to voltage and RPM. For an example: Say you had four coils and at 500 RPM there was a 3 degree difference in timing between the fastest and slowest coil on 12 volts DC. (one millisecond is 3 degrees at 500 RPM) This difference would likely go unnoticed at that speed. At 1000 RPM the disparity would be 6 degrees. At 2000 RPM the disparity would be 12 degrees. Assuming you split the difference, one cylinder would be firing 6 degrees too advanced and one would be 6 degrees retarded. Now, if you were operating on 6 V DC, all of those figures would be doubled.
How can one check for this inter-cylinder timing disparity?
A HCCT shows double sparking, but how would one know if each coil fires at the same voltage with the coil testers? Or is that the reason to have a HCCT with both a voltmeter and ammeter? In that case which is more important, the voltage being the same or the ammeter reading the same for each coil tested? I can adjust ammeter reading by bending the point mounting metal, but how could one adjust voltage without changing the wire coil resistance?
P.S. See what happens when you post--you get more questions!!!
Hope Sue and you have a great 2013!
That's where the ECCT comes in. Each coil can easily be adjusted to fire at precisly the same time to minimize coil to coil (cylinder to cylinder) ignition timing variation to achieve optimal engine performance.
I think even with the ECCT the lag of the 6V powered coils will be a problem.
Arnie, I don't mind answering questions. You cannot find out the "time to fire" easily on a HCCT. I think Mike Kosser's ECCT will address this. I do it one of three ways:
1. With a duel trace oscilloscope attached to the primary wire of the coil box and the magneto, the four coils can be compared to the voltage waveform of the magneto. This test is made with the T running on battery. The unloaded voltage waveform makes a fantastic "degree wheel"
This gives you an idea. This is actually an E-timer trace, but the concept is the same. In this example the "time to fire" is about 4 ms. This is important, but what is more important is that all four cylinders (only one is shown) fire at the same point on the wave form.
2. Again with a 'scope. The 'scope needs to capture and have a triggered sweep. Just hook up a coil and note the "time to fire". If you have four coils that have the same "time to fire" time, they should be fairly well balanced.
3. Have four coils with known similar characteristics set up on a HCCT. The theory here is that if four coils have the same specs in regard to impedance, copper and iron losses and so on, they should have nearly the same "time to fire" time if set up to pull the same current on a HCCT. I believe that the easiest way to find four coils with similar characteristics is to buy four new (such as the new Bittner) coils.
For a little more information see my "Bucket Analogy" article written for the Montana 500 newsletter.
Of the three methods listed, I think number 1. is the best.
By the way Arnie, thanks for the good wishes. We are doing well, and I will tell the wife your message!
Jim, you beat me with ECCT message. I didn't mean to be redundant.
Do not understand.
The ECCT checks with the spark plug attached.
What if the gap in each of the spark plugs is different? Would that cause a coil to fire at a slightly different time/voltage? In other words how would one know if the ignition coil is at fault or some other part of the ignition system at fault? I know that the spark gap at atmospheric pressure is not as critical as under compression, but this was just to give an example.
I guess what I am looking for is to judge each component by itself. That way I would not say a coil is bad, for instance if the spark plug did not fire because of a carbon track in the plug itself. Another example would be if the timer contacts do not fire (or ground out in this case) at exactly 90 crankshaft degrees. If that was the case perfectly good coils would not fire correctly at the best time for each cylinder, but it was not the ignition coil but the timer that caused the problem.
I guess one could make the argument to include all the ignition system components and adjust to compensate for the problems.
For example in modern vehicles if the air filter gets partially clogged, the exhaust gas sensor may try to adjust the gas/air mixture to account for the partially clogged air filter. However I think a better approach would be to change the air filter.
Your thoughts on the above?
While I was writing my message you already came up with an answer. You type faster than I can! I am more a mechanical person so I do not have a scope to check coils. I have a hammer, ax, saw, pliers, wrenches etc. and was looking for a simple mechanical way to check an electrical device! Heck I cannot even see all those electrons running around in the wires!
Thanks Guys for your replies. Going on---At present running 6volt stock system with coils.Key set to bat because misfires on mag position.It seems I can get better performance if move up to 12volts.I have a nice new 12volt battery .So I change the battery.
Change the bulbs in the lights.
Starter motor now runs at twice the old speed or no??
Will I have to talk nicely to the generator and or cut out??
Or should I keep to the old adage if its not broke dont try to fix it?
Keith, you may be able to do an in car recharge of your magnets and bring the magneto back to life.
If the engine runs, but misfires on magneto (as indicated above) and runs fine on battery that is the classic symptom of improperly adjusted ignition coils.
Before you undertake the in car recharge you might want to try some known good coils (I have some properly working loaner coils you may borrow) or measure the output of the magneto to determine where where the trouble actually lies?
The in car magneto recharge is a bit tricky if you have never done it before and you can cause more trouble than you repair. Before you undertake it you should discuss to knowledgeable folks who know the pitfalls.
Ron the Coilman
Thanks Tom and Ron My point was more about the consequences and pit falls and or advantages of moving from 6volt to 12volt.
to provide my sparks before going down the route of sorting out the mag side of things!!
Regards Keith Granger
Ps cant take up your offer of coil help Ron!
Wrong side of the pond!!!!
Converting a Model T from 6 to 12 volts has advantages and disadvantages.
The coils will tolerate 12 volts IF you are careful not to let them continually operate without the engine. running. They get hot fast and will soon be destroyed.
The Model T generator is a marginal design good for 100 Watts output. Push that limit long and it is toast. If you run the generator on 12 volts you have to reduce the charging current to no more than 8 amps charging rate or you will exceed this limitation.
The Model T starter will tolerate 12 volts if it is in good shape. Doubtful at 90 years of age? There is a 60% torque increase on 12 volts which can be hard on Bendix drives and flywheel ring gear. Using 12 volt battery cables will help reduce the voltage to a tolerable level, but you are still taking a chance.
This is why getting to the bottom of the magneto problem is a better choice for you. If you measure the output to determine the magneto health and/or get your coils properly repaired you may get a nice surprise and not have to convert to 12 volts.
If you live in Europe there are at least two fellows who rebuild coils and one in Australia.
With all due respect I frankly think you are chasing the wrong problem.
Ron the Coilman
I had a '26 Coupe that acted just like you say, so I just drove on Batt all the time. The coupe would still go 38 MPH, which was scary fast for me!!
I had always thought of doing the "build up the thrust surface on the main cap" procedure, but never got around to it. I had also thought of getting one of those bronze accessories that goes on the front to eliminate the excessive end play.
But, like I said, I just kept driving on Batt. I put several thousand miles on the car while I had it, and it always ran the same. I did have the coils done by Ron, and that sure helped!