69 Coil Wire repair

[Richard B.]

When installing some new shielding on my BB I pinched and shorted out the yellow wire going to the positive terminal of the coil. The wire current was so hot that it melted the electrical tape along it. For the most part the wire looks good as I peeled away the tape. I was able to start the car but I need to repair a 10" section of the wire. I have been told that this is Resistance wire and that I can not use just any 20g wire to do the repair. The wire harness is only about 12 years old so I don't want to replace it if I don't have to. Can I replace the 10" section of wire without affecting the resistance? What voltage should I measure at the coil? Where can I purchase resistance wire if I just want to replace the one wire?

[Jim T.]

Re: 69 Coil Wire repair

If you cannot find a new resistance wire another option is find a salvage yard. Any GM car that used this wire could become a donor. It can be disconnected from the engine side back half of the the fuse block below the master cylinder.
I took one from a Pontiac 35 years ago. Finding a donor today could be a problem.

[Rich W.]

Re: 69 Coil Wire repair

You could try calling Electric Limited..they may sell the wire separately ..

[Richard B.]

Re: 69 Coil Wire repair

Thanks, it is ironic that I just threw away my old wiring harnesses. I was cleaning out my storage area and figured I hadn't touched this box in twelve years why am I keeping it around. Little did I know.
I will try M&H which is local to me, they made the harnesses I installed so maybe they will sell me what I need.

Does anyone know what the voltage should be when measured at the positive terminal of the coil. I was told that it needed to be no more then 12 volts.

[Dennis S.]

Re: 69 Coil Wire repair

Richard
The resistor wire limits current, same as a ballast resistor. It does not drop voltage. The static voltage that you measure at the coil depends on whether the points contacts are open or closed, which adds both impedance and inductive reactance into the circuit. You will probably see something close to 12 volts open and around 7 volts closed. Forget about obtaining a meaningful dynamic voltage measurement, either analog or digital, at coil positive with the engine running...only an oscilloscope can display what is actually happening.

Lectric Limited will not sell you the resistor wire only for their harness, even if you previously bought a new harness from them. Neither will they discuss the electrical characteristics of it...evidently it is top secret information. They are more than glad to sell you a whole new harness though.

Let us know if M&H is more cooperative with you.
Dennis

[John H.]

Re: 69 Coil Wire repair

I pinched and shorted out the yellow wire going to the positive terminal of the coil. I have been told that this is Resistance wire and that I can not use just any 20g wire to do the repair.

Richard -

The yellow wire isn't a resistance wire - it's ordinary wire, from the coil (+) terminal to the "R" terminal on the starter solenoid (supplies a full 12V to the coil only when cranking). The other cloth-covered wire on the coil (+) terminal that goes to the bulkhead connector on the engine side of the fuse block is the resistance wire.

[Richard B.]

Re: 69 Coil Wire repair

Thanks John, that makes me feel better, I don't want to have to buy a whole new harness.

I had spliced in 10" of 20g yellow wire and was going start it but when some one suggested that it was the resistance wire I was concerned.

Thanks for the help. I might make the fathers day car show after all.

[Tom L.]

Re: 69 Coil Wire repair

I don't have this problem but I'm asking just for kicks. If the cloth covered wire were destroyed, would it be functionally sound to remove the wire all together and replace it with an earlier ballast resister?