70 Coil Wire HOT

[Mike T.]

We don't have ballast resistors on 70's, so one of the 2 wires that goes
to the positive side of the coil must be a resistor wire.
Both of the wires are covered in a white insulation type material, (similar to what the old cars had for the wire that lead to the temperature sensor in the intake.)
A section of one of the wires (the one that goes into the wiring harness-not the one that goes to the starter solenoid), has some brown to black areas on the white insulation material. It looks like it got too hot.
I touched the wire, and it was hot-almost too hot to continue holding it.
The hot area is right next to the coil. I touched the wire 8-10 away from the coil and it didn't feel hot.
Is this normal?

[John H.]

Re: 70 Coil Wire HOT

We don't have ballast resistors on 70's, so one of the 2 wires that goes
to the positive side of the coil must be a resistor wire.
Both of the wires are covered in a white insulation type material, (similar to what the old cars had for the wire that lead to the temperature sensor in the intake.)
A section of one of the wires (the one that goes into the wiring harness-not the one that goes to the starter solenoid), has some brown to black areas on the white insulation material. It looks like it got too hot.
I touched the wire, and it was hot-almost too hot to continue holding it.
The hot area is right next to the coil. I touched the wire 8-10 away from the coil and it didn't feel hot.
Is this normal?

Mike -

That IS a special resistance wire - it serves the same function as the separate ceramic-base ballast resistor on pre-68 cars. If you leave the ignition switch in the "on" position and the points happen to be closed, that wire will get VERY hot. The other wire that goes to the "R" terminal on the starter solenoid won't, as it only sees current when the starter is cranking.

[Jim T.]

Re: 70 Coil Wire HOT

Mike -

That IS a special resistance wire - it serves the same function as the separate ceramic-base ballast resistor on pre-68 cars. If you leave the ignition switch in the "on" position and the points happen to be closed, that wire will get VERY hot. The other wire that goes to the "R" terminal on the starter solenoid won't, as it only sees current when the starter is cranking.

John your post about the resistance wire getting Very hot if the ignition is on and the points being closed may have explained something to me that occured with my 68 in 1974. I don't remember now how I learned that the resistor wire in my 68 got very hot. I did not want to unravel the electrical tape on the wiring harness to inspect the wire. I just replaced the resistor wire with one from a donor car.
If the resistor wire only got very hot near the coil on my 68, possibly the wire could still be used. I was concerned that it may have burned into other wiring in the wiring harness. I may just leave it alone since I have had no problems since 1974 in this area.

[Mike T.]

Re: 70 Coil Wire HOT

My wire is just hot near the coil. I peeled the tape back, and the wire isn't hot where it enters the wiring harness.