Hello All, First post here in this forum...
A friend of mine purchased a 1912 T (not sure of the exact specifications) and we are having a problem getting it started. Quite honestly, I'm not much of a car mechanic - more of an enthusiast, but I'm learning as we go along.
Anyways, we tested each coil and we can verify the output voltage to the plugs and hear each coil "buzz" when we apply 12V across the terminals on each one. When we put them back in the coil box, so all 4 of them are together, we only hear a single coil (coil for cylinder 3) buzz when we turn the ignition/coil box to "BATTERY". If we then turn the crank, coil 3 stops buzzing, and doesn't start buzzing again until approximately two revolutions of the crank.
Again, this is new to me, but shouldn't we hear all 4 coils buzzing at some point when we are hand turning the crank? I would have thought that at different points in the rotation, the magneto would open/close the circuits to each of the 4 coils.
Assuming you start turning the crank with the #1 piston coming up towards top dead center, each cylinder's coil should buzz in sequence, 1, 2, 4, 3 as you turn the crank. They should not all buzz at once. As you found, each coil should only buzz once every two turns of the crank.
Sounds like things are working properly to me.
Sounds like you have a timer or timer wiring problem. I'd start by removing the timer (Front of engine on end of cam shaft) and clean it. It sounds like you are only getting contact on the #3 contact inside.
Thanks Hal, my mistake, I didn't pick up on David's comment that only coil #3 was buzzing, sorry.
All, thanks for your feedback. I'll pass this along to my friends. One of which is a retired Master Mechanic for Cadillac.
Check the coil box spring contacts inside the coil box that holds the 4 coils. There are 3 connections per coil and they need to be making good contact at each coil. That and the timer determine which coil gets power. You are on the right track checking the ignition first and yes you should get a spark at each location. As you hand crank you should hear a different coil buzz at every half turn of the hand crank. They don't have to all "sound" exactly alike at this point but they do all need to buzz. Coils do not buzz when you have selected MAG on the coil box switch but they should indeed buzz when you have set the switch to BAT. Be careful not to let the coils sit and buzz when you are using 12V battery since they can overheat. Once the engine starts the duty cycle drops off and they can run fine on 12V with no harm. ALso do not buzz the coils when there is nothing connected to the spark connection and a suitable gap to ground since that can hurt the coil by causing it to arc internal to itself.
Double check your wiring especially to the timer. You should send your coils off to be professionally adjusted by one of the coil experts on this forum, as the sound of the buzz alone will not determine whether or not you are getting maximum performance. Ron Patterson did mine and is exceptionally good. Jim Patrick
PS. I forgot to include the wiring schematic. Some schematics are wrong and if you use them, your wiring will be wrong. This one is guaranteed to be right. Here you go. Jim Patrick
What does an electric start car wiring diagram have to do with a 1912 ???
Jim - I'm assuming that schematic doesn't apply since the car in question is a 1912. It doesn't have an electric starter nor does it have electric headlights.
Ron the Coilman
These are correct for 1909 - 1914:
David, I am just south of you about 1/2 hour. If you need some help let me know.
Doug, thanks for the offer. I may take you up on that stay tuned.