MTFCA Forum

My brother and I have recently purchased a 1926 Model T roadster pick up ( I think this is the correct term it is a convertible)
Unit was half restored and we are looking for advice on the ignition coils. Unit came with a all in one box (would not start FYI) and we wanted to put it back to original so we purchased 4 reman coils from Gaslight Auto Parts. Once installed we can not get them to ignite. We have 6.7 volts to bottom of the box, 6.7 volts coming out of the box at spark plug wires & 6.7 volts at spark plug still no hum or fire at plug. Any advice would be appreciated

I suggest you buy an owners manual, Gas light should have one that cover your year. Learning terms and what parts are is part of the hobby so we can all be on the same page. At the least look up "mtfca; ignition system" on google or your search engine to get you started. Are you using a timer or? You would not have 6.7 volts coming out the spark plug wires. So without photos of how you are hooked up, or more information I think at this point might be hard to help.
Thanks Chris or Jeff for moving it.
http://www.mtfca.com/discus/messages/41 ... 1414969907

Good on you! Calling it a Roadster pickup is great! These guys and me love the pickups.
How's your timer/commutator? Clean? Or fairly clean? Clean it up and try again
You'll love the sound from that coil box and those four coils when you get it sorted.

Dante,

Mark has given very good advice, but I have a suspicion around what's happened...

If you look at your coils. the bottom connector is for the +6V feed, the top connector at the side is the ground (-6V), and the lower side connector is the EHT output to the spark plug.

These correlate to the coil box you've described thus:

(1) The very bottom lead underneath the box should be 6V from the ignition switch
(2) The lower row of the four side connections should go to each corresponding plug
(3) The upper row of the four side connections should go to the timer at the lower front of the motor

If you're getting 6V at the plugs it seems likely to me that you may have (2) and (3) transposed (ie. the upper row is connected to the plugs)? If so, swapping these around may be all you need to do to make the motor run,

With (3), if your wiring loom is tidy it should be obvious which leads go where, but if not you should follow Mark's suggestions and look for a diagram that will show you which of the timer connections/wires goes to which coil...

Good advice to new T owners is to get the manuals and study them to learn about basic Model T parts and how they function. By studying the manuals you can save yourself lots of time and learn what NOT to do with a a T.
The Model T service manual or the “bible” as T owners call it is a must have along with the MTFCA manuals for different aspects of the car.
Model T’s have 100 year old technology and it’s a relearning curve for some folks.

He said the car came with “an all in one box”. I’m thinking this is a “True Fire” or similar ignition system. He replaced that with regular coils, but didn’t mention doing anything with the timer or wiring... I think some of those “spurious” ignition systems include timer and/or wiring modifications that would prevent proper coil operation...

If I may, I would like to add to Adams post above, he is definitely correct, if it has Tru-Fire which it appears to have, it definitely has an entirely different "thing" down in the commutator cover. He will need to "gut" it, and indeed if I remember from my former '20 that had T.F., there is a slight difference in the wiring up to the posts on the firewall. Likewise, he needs to BE SURE to verify if
it even HAS a magneto! Much to my surprise, on my 20, there was NONE. I suspect this is often why someone converts to the electronic ignition gizmos, either due to a dead mag, or the total absence of one. Just my two cents.

A bunch of experienced Model T guys couldn't figure out how come there was no spark...

...until Verne came back from lunch and pointed out what we obviously had wrong.

This shows correct wiring with a normal timer.

Dante, please take the lid off the coil box and take a picture of what is inside, that will settle whether it is Ford standard coils or some aftermarket box.

If you're feeling brave, please also remove the timer cover and take a picture of the inside of the cover and the timer rotor on the front of the camshaft.

Without seeing what you have, we can only guess on how to help.

Steve your close up of the coil box wires shows how things can get upside down without thinking about it!
I had to look twice or so before I caught on what’s upside down. Guess I’m getting old and slow. Good point to bring up though. Those simple things can drive you nuts sometimes.

Mark, you're right, he should definitely remove the timer cover. Cause as I still bet with Adam, that it had a Tru Fire setup in the coil box orignally, that he just removed, thinking by only putting in 4 "standard coils" would do the trick. Not possible. The T.F. electronic rotor mechanism will have to be removed, and some preferred form of timer rotor installed, and again, it seems to me there's a slight difference with the wires going up to the firewall. Seems mine had one going from some coil post to ground but it evades my lame brain now, as I haven't owned the car in over a year.

And assuming this is the case, as I said, then he has to figure out WHY it had the T.F. in the first place. Faulty mag? Or no mag? Or just maybe the former owner wanted the experience. When working well, the T.F. does perform nicely. Enuf said.

As far as I recall, the only deviation from the standard wiring when fitting my True fire was the addition of an earth wire. All that should be needed is to remove this. Otherwise, changing the rotor button and electronic timer for a standard roller/brush type timer is all that is needed.

Allan from down under.

Thanks for all the advice, we are working on unit tomorrow and I will advise..
Happy New Year!

I would suggest that you do a continuity test and the timer wiring. Disconnect all of them from the coil box test each one individually by hand cranking the engine; If good connections no need to remove the timer cover. Not sure if this would work on T coils but works on distributor condenser. If you test for continuity of the coil with a multimeter (this action actually puts a charge into the coils condenser) see below...
READ THIS so you don't shock yourself regardless of testing the coils https://www.ifixit.com/Wiki/Troubleshho ... components

Basically To test the capacitor with a multimeter, set the meter to read in the high ohms range, somewhere above 10k and 1m ohms. Touch the meter leads to the corresponding leads on the capacitor (T coil), red to positive and black to negative. The meter should start at zero and then moving slowly toward infinity. This means that the capacitor is in working condition. If the meter stays at zero, the capacitor is not charging through the battery of the meter, meaning it is not working.

Looks like we are on our way to getting the T running.
Thanks to Brent Mize for his help with the coils, timer and house call.
Correct on the conversion of the true fire, we had to convert timer back to original option and we got her to fire.

Again thanks to everyone for your input. Looking forward to this project..