[Double A]

'68 LeMans--- I've always heard of one (1) wire of the original engine harness (pink, the former coil+) going to the HEI, but changed to a larger gauge.
However, on two spare harnesses I have, the pink (coil) wire is spliced with a black/yellow wire (mounted next to the pink on the firewall fuseblock).
I don't have a schematic; do both wires need to be together before being connected to the BATT terminal of the HEI? And what purpose does the yellow/black wire have?

Thanks 4 much-needed help [img]/infopop/emoticons/icon_smile.gif[/img]

[Double A]

'68 LeMans--- I've always heard of one (1) wire of the original engine harness (pink, the former coil+) going to the HEI, but changed to a larger gauge.
However, on two spare harnesses I have, the pink (coil) wire is spliced with a black/yellow wire (mounted next to the pink on the firewall fuseblock).
I don't have a schematic; do both wires need to be together before being connected to the BATT terminal of the HEI? And what purpose does the yellow/black wire have?

Thanks 4 much-needed help [img]/infopop/emoticons/icon_smile.gif[/img]

[Blackcat]

The wire to the coil should be black. It is a resister wire. By changing it out at the plug to the fuse block gives it a full 12 volts. It seems that you have a modified wireing harness. If you want you can find a plug in at the fuse block that works with the key and put your coil wire there.

[george kujanski]

The black/yellow wire provides full battery voltage to the coil during starting. This wire goes dead when the engine starts and you release the key. The other wire is used during normal running, however, it is a resistance wire and it lowers the voltage to the coil during normal operation. For the HEI, you must bypass this wire with a 14 or 12 gauge wire so the HEI gets full voltage during normal operation. You could remove and replace this wire from the coil to the fuse block and you will be good to go.

Regards, George

[Triggerman]

GK, Welcome Back! TM

[george kujanski]

Thanx, TM, I never really left; not too many topics recently where I thought I would offer useful info... BTW, do these posts count towards senior membership? LOL....

Regards, George

[Double A]

Thanks, George; I talked with an "old dog" mechanic that I work with and he specified the same thing before you replied.
"Tis a good thing to have confirmation"

...off to the store to grab 12-gauge wire...

Thanks again, Double

[Tim Corcoran]

In my 67 LeMans I converted over to a pick-a-parts HEI that I recurved for the new 428 motor. The car originally had two wires going to the + side of the coil, a white one and a (I think)black one. The white wire was not copper looked like some kind of steel wire while the other wire was copper. The white one had 12.4 volts when the key was in the on position and the black only had voltage (12.2 volts)when the switch was in the start position. Since I had 12+ volts on both wires I guess that neither was a resister wire. In fact I believe there was a resister ballast on this car on the firewall before I took the 326 out. So what I did was just hooked up both wires to the BAT post of the HEI? Any how the car starts with just a click of the starter and runs great. Wish the race car started this fast. Did I do it right?

Tim

[george kujanski]

The HEI is designed to operate with full battery voltage to the "BAT" terminal. Granted, it also works at much lower voltage such as encountered while starting at low temperatures.

If you have a ballast resistor on the firewall, simply bypass it, connect the wires that go to it together. If, in fact, one of your original wires was a resistor wire you shoould bypass that wire for proper operation.

Not supplying full voltage to the HEI could manifest itself as not providing enough spark voltage at higher RPM.

BTW, the voltage measured at the coil with a resistor wire will be different depending on whether the original points in the distributor are in the open or closed position. With a resistor wire, and the points closed, you will probably measure 6-8 volts at the coil; battery voltage with the points open.

Regards, George