Bottom Line Up Front: What is required to use the non-starter coil box with the switch on the front on a starter car with a dash ignition switch?
Hi, I’m trying to help Dan out a little with his new chain drive Model T Truck [from his posting at: http://www.mtfca.com/discus/messages/411944/505530.html ]. I only have a few of the puzzle pieces so far, but I don’t want to cause him to “demagnetize” his magneto. He has an earlier coil box with the switch on the front of the coil box as well as an ignition switch on his dash as shown in the photo below of his truck cab.
I have e-mailed but I have not heard back if the car was running when he obtained it or if it has not run at all since he recently acquired it. He is working to rewire it. I’m 90% sure that if he had one of the coil boxes that did not have the switch on the front he could follow the standard wiring diagram for a starter equipped car and he would be fine. But he also has a switch on the front of the coil box. “IF” the coil box and coil box switch have not been altered and are still as from the factory, I would guess he would leave the switch on the coil box turned to “Mag” and wire it just as though it had 9 porcelain insulators coming out of the back rather than 10. I.e. like the illustration below that Bill Aber posted:
And then the dash ignition switch would do the changing from battery to mag etc. Do I have that correct? And if so, he might want to just remove the key, turn the switch on the coil box to mag (a fence staple works great for that – we used that for many years before we had a real key) and just leave it in that position.
If the above is correct the other question I have is – can a previous owner easily have messed up the coil box wiring so that the plan above would not work? From what I know of the coil box switches they are robust and provide good connectivity. They are like a rotating “blade” switch. Is there an easy way to check that the coil box and coil box switch are still wired the way they were originally wired? I was thinking he could use a small flashlight battery continuity tester -- lights up or beeps etc. if you have continuity. But I’m not exactly sure where to hook the leads. Step one disconnect the wire leading to the magneto pickup on top of the transmission. [CAUTION do NOT apply any voltage that might some how go to the magneto contact on top of the transmission. That could demagnetize the magneto – not a good thing]. One test lead would probably be on the Mag terminal on the back of the coil box again the lowest one on the side of the water inlet. But then with the coils out of the coil box as shown – where would he put the other lead to complete the circuit?
I did try searching the forum but I did not find that answer and I want to quit for the night and I don’t want to find out he inadvertently killed the magneto when I check back tomorrow. I like Rob Wolff’s photo below, but I’m still not sure how we would check to make sure the switch on the coil box and the coil box were working normally as Henry originally set them up.
Thanks for any help you can provide to Dan. The pre-starter cars are a lot less complicated and they don’t leak oil around the starter or generator.
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I'm not sure what I did wrong on the last image, but I will try to post it again. I would like to know where Dan should hook up his battery operated test leads to ensure the coil box and coil box switch are working as they originally were designed.
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