68 Coil Wire Question

[Kurt B.]

Gentlemen;
On a 1968 smallblock, how does the wire that comes out of the harness at the firewall and connects to either the positive or megative side of the coil (not sure which) reach the coil once the ignition shielding is in place.
I have not yet purchased my shileding and have never seen a Corvette with the shielding attached so I am wondering how the wire gets into the chrome box that houses the distributor and coil.
Does it go under it or is there an opening for this small wire to enter.
I ask becasue I am going to cut my existing wire and splice in a new piece that is of the right color and size and want to know how long it needs to be.
When I purchased this vehicle in 1972, the shielding had been removed and the Assembly Manual is not much help, at least I can't find a page that shows the positioning of the wire.
Thank you in advance for all input.
Kurt Bunting #26406

[Joe L.]

Re: 68 Coil Wire Question

Kurt-----

The wires in question pass through a rubber grommet which fits into a u-shaped cut-out in the rear of the distributor shield.

[Kurt B.]

Thank you Joe *NM*

[Jim T.]

Re: Thank you Joe

Kurt you mentioned that you are going to cut the ignition wire from the wiring harness to the coil and splice in a new piece that is the correct color. The wire from the fuse block on the engine side of the firewall to the coil is a resistor wire. This wire reduces the voltage to keep the ignition points from burning. This wire replaced the resistor that mounted on the firewall of earlier cars. Are you splicing in resistor wire or other type of wire?

[Kurt B.]

Re: Thank you Joe

Jim,
Boy am I glad you responded to my post because I knew nothing of this resistor wire you speak of. Someone had spliced in a wire and I was going to remove it and splice in a correct regular wire as per the color in the wiring diagram.
I haven't done the research yet to determine what the proper gauge and color should be. I assume it will go to the positive terminal of the coil.
I did not know about "resistor" wire.

Would certainly appreciate any further input you can provide as I almost screwed up here due to my ignorance of the wiring.
Can I buy "resistor" wiring and what gauge and color do I need?
Engine is L79 327 with 350 horsepower, I have A/C, P/S. P/B, Power windows, don't know if any of that matters but hought I should give you as much info as possible so I do this correctly.
Thank you for alereting to this potential problem I was about to create.
You saved my butt and I appreciate it.
Kurt 26406

[John H.]

Re: Thank you Joe

Kurt -

That resistance wire shows as a 20-ga. white/red/black, and is cloth-wrapped in those colors to differentiate it from regular wire; you might try Lectric Limited, M&H Fabricators, or Factory-Fit for a length of it - all are reproduction GM wire harness manufacturers.

[Kurt B.]

Re: Thank you Joe

Thank you John.
I just purchased correct spark plug wires from Lectric Limited and they sent a catalog so I will look in the catalog for this wire tonight.
Can I assume that this wire can be soldered and spliced like any regular wire or is there any special procedure to be used with this stuff?
Thanks again,
Kurt

[John H.]

Re: Thank you Joe

Kurt -

No special process required - just solder or use an insulated butt crimp connector.

[Kurt B.]

Re: Resistor wire

John,
I sent e-mail to the three vendors you recommended for the resistor wire. Nothing yet. I looked in the Lectric Limited catalog and there was no listing for just resistor wire, mostly harnesses.
Would a auto parts store sell this stuff and what is the chance of getting the correct color code?
Will keep trying,
Thank you,
Kurt

[Doug Flaten]

Re: Thank you Joe

John,
I have always wondered if there was anything special about the resistance wires. Were they just of a certain gauge such that they had more resistance in a circuit where you might normally run a bigger wire? Or were they of a specific construction or something that created more resistance?
Thanks,
Doug

[Kurt B.]

Re: Resistor wire

I heard from one of the vendors and apparently to get this short piece of wire one needs to buy a harness for $173.00.
I only need 10 or 12 inches of wire.
Also, the only vendor that responded to my inquiry, (Factory-Fit Inc.) cautioned that unless I had the exact length of wire, it would change the resistance. Even an inch or so difference would make an electrical difference in the resistance of the wire. This is over my head.
Anyone have any other sources for 12 inches of 20 gauge resistance type wire?
I also tried local junkyard but no luck.
Thank you,
Kurt Bunting

[Mike M.]

Re: Resistor wire

Kurt: i have a rol of AC Delco 12 ga fuible link cable. if AC Delco can't supply the 20 ga you need , perhaps one of the electrical engineers who frequent this forum could tell us how long apiece of the 12 guage is equivalent to a foot of the 20 ga. if you can use a piece of my stuff, hollar and i'll send you a piece on the house. mike

[John H.]

Re: Thank you Joe

As far as I know, they were a unique construction that provided "X" ohms per foot of resistance, which is why they were made with the woven cloth insulation for identification - it was less costly than the separate ballast resistor and mounting provisions. Perhaps someone with more electrical knowledge can enlighten us.

[Doug Flaten]

Thanks John

I'll post the question back at the top. I have always thought they were special construction too, but did not know what to look for if I went shopping for one.
Doug

[Jim T.]

Re: Thanks John

Kurt I have been out of town. Anyway I will tell you what I did to replace the resistor wire in my 68 back in 76. I went to a wrecking yard/salvage yard and removed a good resistor wire from a GM donor car. I believe it was a Pontiac, it does not really make any difference. I cut or unrapped the tape and removed the resistor wire from the wiring harness. This will be from the coil connection to the fuse block located on the engine side of the firewall. If you need more information for this replacement let me know. I am still using this donor car resistor wire and it is still runing great. I can't remember the exact reason I replaced this wire, only remember that there was a problem with the resistor wire coming from the fuse block.