I have a 1970 Cutlass 350, mostly stock with points ignition. I had an engine compartment fire, and have replaced all the wiring, plastic and rubber components, plus top-halfed the motor to rebuild the heads and replaced the intalke manifold. I put in a new distributor, carb and coil. After running 20 or so sweet miles, I parked. 30 minutes later, she wouldn't start. The ignition coil was incredibly hot. It toasted, and I'll have to replace it, but before I burn out another one, I thought I'd try posting here.

I'm trying to figure out if I was supposed to have a resistor on the coil, if so, what kind and how to install it? My old one had a condensor (which I also replaced), but no apparent resistor anywhere in the wiring. Could I have simply wired the coil wrong? Can anyone help?

 

Sounds like you need a resistor. I did the same on a boat I rebuilt, smoke a new coil before I figured it out. When I got the new coil it had a part # for the matching resistor.

 

Yes. The factory harness included a calibrated resistance wire to the coil. In Start, the resistance was bypassed for full 12v to coil for quick starting. When the ignition switch was released to Run position, it switched the coil power feed to the resistance wire which dropped the coil voltage down to about 7 volts. This was to keep from burning points quickly, but it could also affect the coil.

Factory wiring had two wires to the coil (+) terminal- a yellow wire that ran back to the starter solenoid for 12V when starting, and a pink wire that is usually inside a protective sleeve, inside the taped wiring harness. It runs back to the front body connector, and from there to the ignition switch.

You can eliminate having to fool with it at all by simply changing to an HEI distributor, which runs off constant 12V with no resistance. A Pertronix electronic conversion also runs off 12V.

If you keep it, factory spec is a 1.35 ohm resistance in that wire. You might have to experiment a little to get the coil running voltage to around 7-9 volts.