Resistor Wire ?

My 74 with the 304 V-8 with the factory distributor uses a ''resistance wire'' in the wiring harness from the firewall connector plug to the + side of the coil.(has a pink insulation) rather than a ceramic resistor. Any ideas on a source for this wire? I do know that it says in the TSM that V8 uses a different ohm value wire than the 6 cyl engine. Thanks for any suggestions. Jim

 

Just looked at both of my 74 wiring diagrams (not factory)and neither shows the resistant wire? Is there a specific reason you need to change this wire? They usually don't go bad. As you know, this resistance value wire is specific to a coil that is specified for this model use.

 

I am planning on a complete new wiring harness for my jeep when I start my rebuild/overhaul. New wire, connectors, terminals and so on are easy to find. The resistance wire in my harness probably will need replaced also, at least I am thinking it probably won't have much life left in the insulation even if still looks good. A lot of the other wires have considerable dry rot on the insulation places. After all it is 47 years old, I want it to be dependable when my daughter and grand kids inherit it. The Jeep factory TSM wiring diagram shows the resistance wire from the plug together junction on the firewall to the + side of the coil. I will only need a new wire about 3 feet long.
I suppose I could use a ceramic resistor with conventional automotive wire if I had to, It would just be a cleaner install without it.

 

How about an internal resistor coil and just forget the resistance wire?

 

Ah, I had not thought of that, guess I knew it, just did not occur to me! humm wonder why.

 

It is a single-strand nichrome wire. No reason to think that it's worn out or failed. I would reuse it. Difference in value is probably because of the routing and different length of wire needed for the application.

I suggest you substitute plain wire and a fixed resistor if you want to replace it. Buy a ballast resistor and mount it on the firewall.

The circuit bypasses the resistor when starting for improved starts. You will lose this feature if you use a coil with an internal resistor.

Wrong forum for this question BTW.

 

More -

Possible you could take apart a junk toaster if you needed replacement wire.

From what I recall, the resistance wire is a bare wire in an insulating PVC sleeve. You should be able to slide the sleeve off and replace it if you choose. The stuff is a nickel-chromium alloy and it's never going to corrode. You cannot solder to it - it must be secured in the connector by an excellent crimp.

Handmade Electronics sells teflon sleeve that would be perfect as replacement sleeve. Teflon tubing insulation for wire Natural color tubing also at McMaster-Carr, "spaghetti tubing."

Nichrome + teflon -> last forever.

 

Humm, sorry, Should it be in the Intermediate forum?.

 

Good site, thanks that is what I was looking for. I did see single-strand nichrome wire for sale but it was uninsulated. If I determine my wire insulation if bad I can just buy a sleeve and keep my original wire.

 

A '74 is an Intermediate. Just a fact - no need to apologize.

 

It's not marked as a resistance wire on the diagram. Look at https://oljeep.com/gw/74_tsm/22-WiringDiagrams.pdf page 22-6 wire C-38.

 

Sure is Tim and for the 8 cyl it's 1.35 ohm. Tnx