by droopsnoot » Fri Nov 15, 2019 10:50 am
If it's like a HC, then the opposite is true - the ballast resistor (it's in the loom on a HC) is running all the time *except* when cranking / starting, and during that time there's a by-pass wire from the starter motor that delivers the full voltage to the coil.
No idea why it would get so hot - it'll always get a bit warm because the drop in voltage has to go somewhere. Can you measure the resistance across it, in case that gives someone any clues? If you have the ignition on for a long time without the engine running, I have heard that would cause the coil to get warm, so maybe it's something to do with that. Maybe it had just reached some critical point when you started the car.
I'm not surprised it's running with the resistor bypassed, but it may shorten the life of your coil if you run it at the full 12v if it isn't designed for it.