Wiring experts needed.....

[ron19]

Ok, I've made some progress (I know, I need to post pics, I'll get some soon, it does look bad azzzzz), anyway, I'm wiring the new motor up and have run into some problems. As you can see in these attached drawings, typically I would run the yellow wire to the MSD box to enable it to start. But, I'm going to run a mini starter, and they don't have the R or relay pole a standard chevy starter has. What I "think" happens, is that when starting, the coil gets 12V from the R post on the starter and when started and ignition switch is put to the run position, the 20P (depending on year, this example is from a 64, 65 has white/orange/purple) becomes hot with 12V and continue's to run the coil.?.?.? That's what I see from this diagram. So if I don't have a R pole on the starter, I'm thinking I may have to get an automotive relay, and run that off the S pole on the starter (16PPL) and run the contacts to the yellow wire, and the yellow wire also to the MSD box. This would provide a temporary, starter circuit hot to the MSD when starting. Does any of this make sense to anyone else? Am I on the right track?

Thanks.

[protrash64]

S pole is 'solenoid'....it only gets juiced when your key is in the start position. If you are planning on using the solenoid (purple ) to activate a relay with battery power it would work. You are creating a 'switched' power source out of a continuous power source with the relay.

I think that 'R' terminal is just a junction. I dont know why they did it this way.

[ron19]

Originally Posted by protrash64

S pole is 'solenoid'....it only gets juiced when your key is in the run position. If you are planning on using the solenoid (purple ) to activate a relay with battery power it would work. You are creating a 'switched' power source out of a continuous power source with the relay.

Isn't the S pole juiced when the key is in the start position? Thus causing the starter to turn the engine over?

[protrash64]

Yes, you are correct......I was thinking correctly and wrote wrong! I went back and fixed it........

[ron19]

Originally Posted by protrash64

Yes, you are correct......I was thinking correctly and wrote wrong! I went back and fixed it........

LOL, that's all right. Now, with adding a relay, would that basically be doing the same thing that the stock starter with the R pole is doing?

[protrash64]

yes, if you are feeding battery power thru to the coil.

[ron19]

Ok, cool and thanks. Funny thing is I do electrical work for a living, and I just couldn't understand why they wouldn't have the ignition (20P) hot while the key was in both the starting and run position. Wouldn't that be much simpler?

[protrash64]

Its wierd to do it that way and you would have to figure out if the relay can power the solenoid correctly(S terminal). If that part works, your battery power is right on the starter. You could use this to feed the coil.

[protrash64]

Originally Posted by ron19

Ok, cool and thanks. Funny thing is I do electrical work for a living, and I just couldn't understand why they wouldn't have the ignition (20P) hot while the key was in both the starting and run position. Wouldn't that be much simpler?

It mite be hot in both.......but the alternator takes over once the engine fires......I think Im getting too tired to think about this!!

[ron19]

Originally Posted by protrash64

Its wierd to do it that way and you would have to figure out if the relay can power the solenoid correctly(S terminal). If that part works, your battery power is right on the starter. You could use this to feed the coil.

Actually, what I thought about doing is when the S terminal is hot, to jump a wire from the S to the coil on the automotive relay, also jump a hot from the battery lead on the starter to the common on the relay, and the N.O. pole on the relay to the coil (or MSD in my case). Then when the key switch is set to run, the 20P wire takes over........

Does this make any sense?

[ron19]

Originally Posted by protrash64

It mite be hot in both.......but the alternator takes over once the engine fires......I think Im getting too tired to think about this!!

I hear ya! Thanks for walking, err typing through it with me anyway. Though I'm not sure how the alternator takes over after it fires.....ugh. Now I have to go through each wire again......LOL.

Thanks.

[protrash64]

I got ya.....I was thinking of the S going thru the relay....you would hook it up as an auxillary pathway of sorts......yeah, that would be cool.

I was fixing wiring last week and Im wondering if you have that 'cold' lamp in your dash. I didnt know about that 'til my buddy told me. He was old(and new) school GM tech.

[protrash64]

as long as the alternator is hooked to the bat+ somewhere your good.