I'm in the middle of installing a new engine harness for my 72 that has been modified for HEI. The harness has two wires that go to the starter solenoid. One purple and one yellow. The purple wire connects to the "S" terminal on the solenoid. Does the yellow wire need to be connected to the "R" terminal? The old harness had been butchered to accommodate the HEI, but the only wire connected to the solenoid was the purple one. The car started and ran with it this way. The schematic shows a yellow wire between the solenoid and the coil terminal on a points ignition. Since the new harness has the yellow wire going down to the starter, should it not be connected? Also, what do the "S" and "R" indicate on the solenoid?
Thanks, Chumley

 

"S" = power, from the ignition switch, to actuate the starter, via the purple wire.

"R" = 12V power from the starter solenoid, to the points, via a resistor wire. The wire is not used with the HEI, and can be discarded.

Norm

 

The 'R' wire sidesteps the resistor wire and gives the coil a full 12v during cranking. The resistor wire is the 'regular' coil power wire. That's for points systems.

The original resistor wire needs to be replaced or capped and a new full 12v (switched) wire run to power the HEI. But, yes, the 'R' wire is no longer needed.

C.J.

 

Yes it does. Thanks.

Norm

 

Thanks guys, I learned all about the resistor wire stuff when I put HEI in my truck. There is no resistor wire with the new harness since it has been modified for HEI and otherwise is exactly like the stock harness. My question is, what is this yellow wire on the new harness, and do I need to connect it? It seems like it is supposed to be, or the harness manufacturer would not have put it there. Thanks, Chumley

 

The manufacturer would be the best one to ask.

Norm