OK, so have been going through my T Bucket and cleaning up things as I go. Figured I would look into the wiring under the seat, as there was a broken radio (and ***ociated wiring) I wanted to pull out, and saw some other connections fraying or corroded and a bolt where a fuse should be in the fuse block.. all this led to this discovery.. There seems to be two ballast resistors in the ignition circuit. The first seems to be the original, and form what I understand, seems to be correctly wired in for my application i.e has wiring for byp*** on start and through the ballast for run. (1st pic) Locating the coil under the dash, there is a second ballast, wired in line (second pic) right before the positive on the coil which if I understand would now give me two resistors on the line while in run (and one while starting since it cant be byp***ed) Is there any reason for this? What is the proper way to test what voltage I getting where? I am an electrical newbie, but from initial searches seems like I either need to short the negative side of the coil to ground to be able to measure voltage drop across the various resistors, or close the points. Then while in run if a have the multimeter one side to ground, and the other on either sides of the resistors I can see input and output voltages?
I’d check the voltage at the coil when running at the (+) should be about nine. Then check at the wire at the feed to the ballast should be battery voltage. On yours I’d also check the ballast under you seat to see if it’s nine. If it is everything mentioned above will be lower. Also think about all the 6 volt cars built which had no more than 7 volts on their point an lasted for years. I always liked V-dub 6 volt coils on my 12 volt cars.
It may be that a second person replaced the coil at one time and not seeing a resistor right there wired installed one because the instructions on the coil said you had to have one. Not pulling the seat to check the wiring under the seat and not seeing the resistor wired in there they installed one. Jimmy Six hit it spot on, a volt meter is your best friend as you need to see what the voltage to the coil is when the car is running is. The car may have had several owners over the years each one adding something in the wiring that may or may not be needed. Or byp*** an issue but not remove the issue. At least a T bucket shouldn't have many circuits or a lot of wires to deal with and it should be reasonably simple to sort out.
I'm using a new old stock transistorized ignition setup on my car and the instruction sheet specified two ballast resistors. Sent from my SM-T350 using The H.A.M.B. mobile app
this isn't going to help here, at all. We're dealing with a point system. But yeah, it's most likely that someone didn't see the first, and added a second. I would remove the second one you discovered, and not worry too much about it. If you think you don't know what you're doing, you're still miles ahead of the last guy, because you're asking questions, and trying to learn to do it right.
I worked on an old farm truck that had two ballasts back in the early '80s. The farmer said that it was burning points and the "tech" at the dealership hung the second ballast. Guess that cured it. I discovered that the engine ground strap was broken and replaced it. Then removed the second ballast. That cured it too.
You might want to spend a little time here if you need a "refresher course" on points type ignition systems. https://www.jalopyjournal.com/forum/threads/hot-rod-technical-library-basic-ignition-systems.983424/
Hmmm...yeah, I suppose that's possible. Mopar electronic ignition systems use a double ballast resistor in the 70s-80s, one to power the amplifier, one for the coil, iirc.
Yep, so measured the voltage while running. Getting 5 volts to the + coil. Removed the second ballast at the coil, now at low 7s while running.
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