It would back feed 12 volts to the starter when the ignition turns on power to the coil so power would be going to S any time the key was in the run position.

 

Ahhhhhh......... Of course - I just didn't see it!

Thanx all!

 

that wire from the R goes to the coil,it attaches along with the resistance wire on the coil,so when it loses 12 volts the resistance wire is still powering the coil so it would back feed.you turn the key and get the starter turning,even releasing the key and the starter will keep turning,you will have to remove a battery cable to get it to quit.

 

Look at it this way, the S terminal is an input signal to the starter to engage the solenoid, the R terminal is an output signal from the solenoid to the coil+ terminal.

 

How about on the mini starters with only one terminal post?

 

Great with HEI, not so good with points and condenser ignition system.

 

If using a points distributor and some of the older electronic trigger mods that require 9v to the distributor during "run"; you have to use a relay system to toggle between 12 v for starting and 9v for "run".

 

There is also a blocking diode mod that utilizes the S terminal to feed the coil + terminal in place of the R terminal on the solenoid.

 

Thanks Dyno using a Pertronix so I am good! whew!

 

I think I've read on this forum that earlier Pertronix (maybe Pertronix I or II) does require the 9v resistance to the coil. Pertronix III uses 12v.

Yep you did it was a long thread too many opinions also....

Gee guys, now you have my curiosity. I just bought this Pertronix II distributor from Summit Racing 6 weeks ago. I'll be using it with an MSD 6AL box, (if that matters)which the guys at Pertronix said I can use, and I have a Power Master mini-starter (P/N 9500) which doesn't even have the "S" terminal. Could it be that only the "Flame Thrower I" distributors needed the "S" terminal? And does anyone remember the title of that thread you were speaking of??

Here below is the starter I have.....

 

I think I've read on this forum that earlier Pertronix (maybe Pertronix I or II) does require the 9v resistance to the coil. Pertronix III uses 12v.

 

Yep you did it was a long thread too many opinions also....

 

It looks like you already received some good answers here, and I'm sure not any electrical expert either. FWIW, here's what it says in the instructions that came with my aftermarket PowerMaster mini starter:

 

To everyone reading this thread....

Even though you may be using a HEI , MSD, or Pertronix instead of points and condenser ignition, don't assume that will get you off free from needing the R terminal starter and solenoid combination. Since there is no way of knowing how every ignition switch feeds power when in the start position, and how different coils and ignition systems receive power at that time, the best way is to check and be sure the ignition circuit is sending spark to the plugs when the engine is cranking. It may sound like I'm overthinking the situation, but some (many?) ignition switches cut power to the coil when the key is turned to the start position. If there is no spark when cranking, you may have a hard time starting that high dollar engine.

 

FWIW, I wrote to the Pertronix manufacture about my recently purchased Pertronix Flame Thrower II distributor and here below is the e-mail repsonse I received, (although I'm still going to take Dyno John's advice in post #14 and check for spark to the plugs during engine cranking):

"Bill, with our systems you should not need to have any wire coming from the starter solenoid. the old points system used to use a lead from the starter solenoid to the coil, this lead is no longer needed. you should only have the Ignition 12v source from the key switch."
Larry Solis


Technical dept.

lsolis@pertronix.com

 

"Bill, with our systems you should not need to have any wire coming from the starter solenoid. the old points system used to use a lead from the starter solenoid to the coil, this lead is no longer needed. you should only have the Ignition 12v source from the key switch."

So, what they are saying is you must have a full 12V going to the distributor when in the run position on your ignition switch as well as 12V going to the dist. in the cranking position.

 

I sure hope "their" technical department did their due diligence and researched to verify if ALL Chevy's have an ignition feed that doesn't drop during cranking.......Donny with American Autowire had many discussions in the Electrical Section in regards to mutually bussed vs. non-mutually bussed ignition switches.

In plain english:

If you are going to upgrade your ignition system, it's up to YOU to determine if the power feed you are using stays "alive" or "drops dead" during the cranking operation of the key switch--especially if you are going to do away with the "R" bypass feed from the starter solenoid.

 

Yep, I had to do a work around for that on a 58 starter switch.