Hello, I am finishing the wiring on my A-V8. I am running a positive ground 6-volt system with a 59 A-B flathead. The question is, do I need a ballast resistor? This is the wiring diagram that I have been using as the engine came out of a 41 ford. It looks like it is showing a ballast resistor (BR). Looking for thoughts or suggestions. Thanks, Mitch PS I did use the search function.
Well, according to the key, BR means black and red ... But it does say resistance unit right next to it. Weird.
I'm pretty sure you won't need one on a 6v system.. I've never messed with positive ground stuff though, maybe it's different than the early gm stuff I usually mess with?
Why don't you jump over to the Ford Barn and ask them. Surely they would know the correct wiring for your application. Very knowledgable fellas over there and usually quite helpful.
If this is positive ground, and there is only one wire going to the coil from the ignition switch, then isn't it a negative? Or am I just overthinking this?
Overthinking it! Positive ground is simply put: + of battery and any other polarity sensitive device is ground. Negative ground: - of batteryu and any other polarity sensitive device is ground. Either way, one wire from ignition switch to coil is the same either way. The coil terminal may have a + on it. In this case the + of coil goes to ignition switch on neg gnd systems, opposite on pos gnd systems.
If you are running the stock Ford coil that mounts on the dist that system did indeed use a resistor to give 3 something volts to the coil.
I used the crab dist. and 12 volts with a really old delco 12V coil. I guess most new coils have a built in resistor, but redundancy won't hurt anything. The resistor get's super hot, careful mounting. I drilled a hole in the firewall lip and bolted it there, overhanging. If run without resistor the coil will fry, sometimes explode. About 3 bucks at tractor supply in tractor parts asile, or NAPA
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