Second set of eyes please... Coil & Starter wiring

[HawkX66]

I could use a second set of eyes to check out what I'm doing. I'm changing starters from the old GM style with R & S terminals to a new mini starter style that comes on Gen 6 big blocks etc. They hook up the same as a/m mini starters. The new one doesn't run the "R" terminal that goes to the coil on older cars. I've been running a Pertronix III in place of my points and they work great. They're wired like the pic below. What I'm trying to figure out is if I can omit the yellow wire from the R terminal that goes to the coil the way I have it wired. My understanding is the R terminal is only energized during cranking to give the coil a full 12 volts. The way I have it wired is so the fabric wound wire from the ignition switch, which I think is the resistor wire, triggers the relay. The relay then supplies a full 12 volts to the coil and Pertronix in the distributor all the time including during cranking.

[McCune]

How are you going to power up the S terminal on the starter solenoid? You can't jumper the battery to S on the solenoid with a PMGR starter.

[HawkX66]

Originally Posted by McCune

How are you going to power up the S terminal on the starter solenoid? You can't jumper the battery to S on the solenoid with a PMGR starter.

Wouldn't the S term be powered by the ignition switch? I wasn't planning on using a remote relay.

[McCune]

You just want to use the Bosch style relay? If so are you sure that original coil wire stays hot during cranking?

[HawkX66]

Originally Posted by McCune

You just want to use the Bosch style relay? If so are you sure that original coil wire stays hot during cranking?

The Bosch relay is just to power the Pertronix right now. I had to put a full 12volts to it. I think the way it's wired the R terminal is redundant. I do need to verify that it stays hot though. That's really what I'm trying to verify in the end. I guess I made a short story long lol.

[L_e_e]

Would it just be easier to run a new wire from the "IGN" spade on the fuse block to your coil?

[HawkX66]

Originally Posted by L_e_e

Would it just be easier to run a new wire from the "IGN" spade on the fuse block to your coil?

Possibly. Do the "IGN" slots keep 12v power while cranking?
I just found the answer to whether or not the resistance wire stays hot while cranking and the answer is no. So my assumption that the R wire is redundant in my circuit was wrong. When cranking, the R wire puts a full 12 volts to the coil and the resistance wire goes "dead". Once you release the key after the engine starts, the power returns to the resistance wire and feeds the coil.
If anyone thinks I interpreted this wrong, let me know.

From American Auto Wire:
"The points distributor used a resistance to lower the voltage to the points in the run position to prevent wear on the points. This was done with either an external ballast resistor or a resistance wire in the ignition circuit depending on the year of the car. For starting purposes, there was a 12 volt override supplied by a separate wire from the “R” terminal on the starter solenoid to the ignition coil. When converting to an HEI there are three issues which must be addressed. The first concerns the resistance in the run circuit. The second concerns the gauge of wire feeding the HEI distributor. The third concerns the starter 12 volt override and the ignition switch. When using HEI, the distributor requires a 12 volt feed. In order to achieve this the ballast resistor or the resistance wire must be removed from the circuit and replaced with a pure 12 gauge feed wire. This feed wire must be 12 gauge from the ignition switch to the bulkhead and then from the bulkhead to the HEI power terminal. This solves the first two concerns. The third situation can be solved in two ways. The original 12 volt override wire from the starter solenoid “R” terminal to the ignition coil must be retained and must be doubled up with the new 12 volt ignition feed before the wires are plugged into the HEI power terminal. The reason this is necessary is that the ignition switch is mutually exclusive in the crank and run positions. This means that there is no power on the “RUN” circuit when the ignition switch is in the “CRANK” mode. Subsequently, without the lead wire from the starter solenoid “R” terminal, the car won’t start. An alternative solution involves changing the ignition switch to one that supplies 12 volts on the “RUN” circuit when the ignition is in “CRANK” mode. With this type of ignition switch, a 12 volt override wire from the starter is not necessary. Subsequently, if your starter had an “R” terminal and you changed the ignition switch as described here, the original 12 volt override wire could be eliminated."

[L_e_e]

I used a MSD HEI, along with a 2 wire GM mini starter, I ran a 10Ga wire from the IGN spade on the fuse block to the HEI, works great. The original 12V override wire to the starter was terminated, the resistor wire was also terminated and folded into the firewall wire gutter.

[McCune]

For 13 bucks you have a R terminal and Zero stress.

[HawkX66]

Originally Posted by McCune

For 13 bucks you have a R terminal and Zero stress.

Agreed. I ordered one yesterday. I wish I had ordered it when I ordered the starter. Starter is coming today and the solenoid won't be here until at least Friday. Thanks for all the help!