Slave solenoid mod. I dont get it.

[y5mgisi]

AKA the ford start solenoid mod. Most are familiar with it. I just dont understand how it would help starting. My thoughts are that you just added another set of contacts into the mix and more cable to the starter which to me, seems like added resistance. You are still having to actuate the original solenoid anyway. So how does adding a solenoid before the solenoid help anything? Its still getting the heat and still actuating as it did before. So how could it be that adding resistance is a good thing?

 

[Babaganoosh]

I always thought the same thing, I guess it makes changing the starter out easier.

 

[y5mgisi]

I do like the benifet of moving as many wires as possible away from the starter, but thats all i can see.

 

[dhcomp]

I do like the benifet of moving as many wires as possible away from the starter, but thats all i can see.

That is the main benefit.

But, it also keeps power away from the starter, any only supplies power when needed

As opposed to running an Always hot 12v line to the starter at all times.

 

[dhcomp]

And as much as its another set of contacts, its an easily replaceable item up on the firewall.

And, if you have ign switch problems, its easy to gap to get the motor to start.

Ive helped a friend put them in 2 trail rigs, and its a no brainer. Need to do it on my burb.

Your 5.3 doesn't have timed start setup does it? If so, you may not want to do it on that truck though.

 

[wheeler]

Ive also heard people say that a hot wire in a hot area can somehow go bad faster. They had a long explanation that involved electrons and stuff.... I like only having the one wire down to the starter as well though.

 

[y5mgisi]

No it doesnt. It still uses the 90 burb actuator wire.

 

[Fordum]

To be honest, the way most folks do it seems to help, but I would do it a different way.

Supposedly letting the Ford solenoid trigger the GM solenoid via a heavier wire will let the GM pull in harder and close the contacts better.

But, in my opinion, the main two problems with the GM setup, are the heat soak of the factory solenoid which makes it weaker, plus the fact that it both closes the contacts and engages the Bendix.
Pulling in the Bendix slows the armature down and causes the contacts to engage slower and weaker.

Weak contact closure force will cause both contact burning as well as dragging starters.

Personally, I would disconnect the wire or strap between the GM solenoid and the starter.
Run a wire from that terminal on the GM solenoid up to the trigger on the Ford solenoid.
Then, run a heavy wire from the output of the Ford to the power terminal on the starter that the GM used to be hooked to.

Then, the GM only has to pull in the Bendix, and supply enough current to trigger the Ford.
The Ford will pull in full force and power the starter with full current.



Or, just buy a Ford truck..............

 

[dyeager535]

Or, just buy a Ford truck..............

Or get a mini-starter, and forget having to change anything.

 

[imiceman44]

Well what people miss is that the wire engaging the solenoid goes thru the ignition and back to the starter, and the loss is too great so it has trouble engaging the solenoid fully when it's heat soaked.
By putting the ford solenoid, you shorten the line, and you send a bigger cable to the starter.
Now after reading fordum's post, I would do that too.

 

[neverdone]

But you already have a huge wire, (power from ford solenoid), to the starter. A jumper from the power terminal on the starter to the start terminal on the starter, is all you need. I have done this on two trucks and it works perfectly. Not trying to stir sh!t.

 

[Fordum]

But you already have a huge wire, (power from ford solenoid), to the starter. A jumper from the power terminal on the starter to the start terminal on the starter, is all you need. I have done this on two trucks and it works perfectly. Not trying to stir sh!t.

The reason I would let the GM fire the Ford, is purely a matter of timing.

When it is wired factory, the starter does not start turning until the solenoid has fully engaged the Bendix.

If you let the Ford and the GM fire at the same time, and have the Ford powering the starter directly, then the starter will start spinning while the Bendix is still engaging.
We are talking milliseconds here, and there is some inertia in the armature of the starter that will cause a brief delay in starting to rotate.

The only way to determine if the teeth are engaging fully would be with a high speed camera or checking long term wear on the teeth.
And even then, it would probably vary from truck to truck.

Once the starter has taken up the load of turning the engine, I suspect that the solenoid is not strong enough to engage the teeth any farther. Although, during a long crank, they may "walk" farther in as the starter turns.

As long as there is significant engagement when the starter starts turning, its probably not a problem.
If the GM solenoid were dirty and dragging, then the starter might get going before the teeth engaged, which would cause grinding as they were driven together.

The final proof, is if it works. Since it has worked twice for you, that is a good indication.
I just like to err on the side of caution rather then have to replace a starter or ring gear.

 

[neverdone]

I agree with what you are saying. I am trying to get as many wires as possible away from hot headers or manifolds as the case may be. An added benefit is you get at least one, (in the case of my 77's two), fuseble links off the gm solenoid and up where they are very easy to deal with if necessary.

 

[Blue85]

It's simple. The factory wiring through the ignition switch and to the solenoid is too small and too long. As the switch ages and the solenoid ages, there isn't enough current to throw the solenoid properly. The remote solenoid lets you run heavy wire which really wakes up an old starter solenoid.

What confuses me is why some people run their main starting current through the Ford solenoid. This is the "double contacts" mentioned by the OP. I set mine up years ago with the stock heavy wire from the solenoid to the battery. The Ford solenoid is only powering the GM solenoid, instead of the little factory pink wire. Works great, even with reman starters, no hot start problems, no need for expensive or hard to find parts.

 

[ryoken]

What confuses me is why some people run their main starting current through the Ford solenoid. This is the "double contacts" mentioned by the OP. I set mine up years ago with the stock heavy wire from the solenoid to the battery. The Ford solenoid is only powering the GM solenoid, instead of the little factory pink wire. Works great, even with reman starters, no hot start problems, no need for expensive or hard to find parts.

cuz it get's the hot post off the starter for your other feeds... which is a huge part of the advantage.. as we all know wire lugs, etc don't live a happy life down there all exposed to the weather and heat...

 

[80' 427]

I don't like full time power to the starter. Sure it should be fine but after 8 hours on the road turning my 427 3800-4200 I am betting the insulation would be pretty rough looking sitting under those larger tube headers. Instead it runs a short wire up to the solenoid on the firewall. At least if it does arc I can stop it by releasing the key.