Starter Wiring???

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Starter Wiring???

Post by sportster_restorer on Tue Jan 27, 2015 1:56 pm

When I recently replaced my starter on the 74 Laguna, there was a wire coming from the one side of the solenoid that usually was for the starting ignition. By that I mean, I had thought this connection on the solenoid wire was used to deliver a full 12 v during starting to the ignition on pre-HEI cars. So I've got an HEI, and I thought 74 was the first year of the HEI. The wire appeared factory, not like something someone had added.

So what is the function of this wire when an HEI was used? Anyone know why its there? Part of the reason I'm asking is I've found some good deals on later model SBC factory gear reduction starters, and they don't have this additional connection on the solenoid. Although I haven't measured, the later model starters appear smaller and thus lighter.

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Re: Starter Wiring???

Post by dynchel on Tue Jan 27, 2015 2:09 pm

Possibly part of 1974's seat belt interlock fiasco?
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Re: Starter Wiring???

Post by thatfnthing on Wed Jan 28, 2015 2:17 am

Can you post a photo? What color is the wire?

All cars, including pre-HEI, got full 12v from the starter connection to the ignition, fuse box, and horn relay. The only difference is that the pre-HEI cars had a dedicated resistance wire running to the distributor from the bulkhead connector in order to reduce voltage and not prematurely burn out the points. This should have nothing to do with any connections at the starter.
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Re: Starter Wiring???

Post by Bruisr on Wed Jan 28, 2015 2:26 am

Could he be talking about the wire that goes to the "I" terminal on some factory style wires? I remember there were 2 wires going to the small studs on the solenoid. A long time ago I had swapped to an HEI, and still had both wires on the starter. I now run an all MSD setup, but I'm still using the stock style starter. I did have to remove the resistance wire for the HEI, but that went into the bulkhead connector.
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Re: Starter Wiring???

Post by sportster_restorer on Wed Jan 28, 2015 11:58 am

There were two wires going to the small studs on the solenoid. One of course is the wire that energizes the solenoid at the S connection and is used in starting the engine. This is the same for all GMs as far as I know.

However, there was another wire going to the second small stud on the solenoid, I recall this is the R stud. This is the one I'm used to delivering a full 12v to the coil in points-and-condenser pre-HEI distributors. As my 74 is HEI, and I'm pretty sure was HEI from the factory, this second wire  is puzzling as to what its doing and where its going.

Does anyone have a .pdf of the engine wiring for a 74?

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Re: Starter Wiring???

Post by pila on Thu Jan 29, 2015 2:02 am

1975 was the first year for the HEI on Chevys, but Cadillac had them in 1974. My '74 Malibu still has the point distributor on the original engine, which is still sitting on the shop floor, waiting for a new home ! Smile

I just removed the extra wire going to the starter when I did the HEI, and ran a new wire from the IGN spade in the fuse block, to the HEI.
Currently, The starter is a Power Master on the 400, (408) which seems to work good.

I also have a wire from the small starter terminal, that runs up the firewall, with a female spade on it, that I can use to jog the engine when adjusting the valves or other times I want to bump the starter etc.

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Re: Starter Wiring???

Post by sportster_restorer on Thu Jan 29, 2015 11:11 am

I could of swore the 74s were the first year for HEI. I'm pretty certain the original owner swapped this 350 with HEI in place of the original 400 at some point in time. I am gonna check and see if he just connected up the resistance wire from the old points distributor to the HEI, or if he really did feed the HEI with a switched 12v source. As the 350 in the car now is HEI, I'm thinking that extra starter wire may essentially be an artifact where I could disconnect it and nothing changes.
We're supposed to have some dry weather first part of next week so I may disconnect it and see what happens. If nothing changes as I suspect, then I should be able to swap in a smaller, lighter starter.
Thanks a lot for the info.

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Re: Starter Wiring???

Post by WyldeBill66 on Fri Jan 30, 2015 1:20 am

I had a 74 Monte Carlo with the 454 years ago and it had HEI. Bought from the original owner. Little old lady, so I know it was bone stock and all original.

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Re: Starter Wiring???

Post by ant7377 on Fri Jan 30, 2015 7:20 am

On my73 Monte I have a white cloth covered wire on one of the terminals on the starter. I dont have HEI. I cant remember which terminal it goes to. I think the inside one (closer to the motor). Its sheilded with a white cloth type material.I think this a resistance wire? Where does it go when it leaves the starter? I know with a HEI its supposed to have a full 12 volts and points do not. They I get I think 9 and the resistance wire is what reduces it.
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Re: Starter Wiring???

Post by thatfnthing on Fri Jan 30, 2015 4:59 pm

Well, after comparing the 73 & 74 diagrams posted in the sticky, it looks like in both cases the yellow wire runs from the starter to the positive side of the coil. The difference appears to be that in the 73 it grounds the other side through the resistance wire (which reduces overall voltage on that circuit), while the 74 grounds directly through the distributor housing, which would give the full 12v.

As for the cloth covering, I would guess that this is just a heat shield of some sort.
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Re: Starter Wiring???

Post by pila on Fri Jan 30, 2015 5:37 pm

When the IGN key is turned, the starter solenoid has a set of contacts that feed the coil the full 12 volts during starting, it's the R terminal that has the full 12 V during start, and runs to the coil + terminal during start. After start, the coil gets the power ( approx 9 v ), through the resistance that's in the wire from the IGN switch.

If looking under the black cover on an old solenoid with the R terminal, the contacts are visible for the R terminal.

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Re: Starter Wiring???

Post by Sinister on Tue Mar 08, 2016 3:01 am

http://www.maliburacing.com/starter_solenoid.html

Everything you need to know.
I now install these on all my cars.
No longer have hot start problems,from heat of headers.
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Re: Starter Wiring???

Post by pila on Tue Mar 08, 2016 1:29 pm

Those have been around for a while, but luckily I haven't had any hot-start problems....(yet !)
But I have a Power Master starter on my Malibu, which spins the 408 without any problem....

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Re: Starter Wiring???

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