Technical Exciter wire for GM 10si alternator in a 40 ford with a push button start

Hey guys,

Hope all are doing well. I'm trying to install an alternator in my 40 ford. It's a 12v system and am running an 8ba. I'm curious if anyone can tell me where the exciter wire should be connected to? I've the standard locking type column with a key switch like the one in the Pic. Should it be wired to the coil or battery post? Does having a button start change anything? Thanks!!

 

Ignition to Gen Light, then Gen Light to the Exciter.

With Ignition On the gen light see ground via the Alternator.
With the engine running and Alt charging the light sees 12v from both sides and goes out.

If you don't have a Gen light put a diode "in series" from Ign to Exciter [Stripe to the Alt]
This stops the exciter back feeding when the ignition is switched off.

 

Thanks! There is a diode built into the exciter wire so that's covered. Would I be connecting to the Battery post on the ignition or the coil?

 

Oh! Just saw the image, I don't have an "ignition" post guessing that's the same as "coil". Still learning! Lol thanks!!

 

I wire the excite wire to the accessory buss, if I don't have an idiot light. Many many years ago I learned that wiring the excite wire to the ignition side without an idiot light caused a feedback and kept the engines running. The light provides a path to indicate charging but won't feed back to the ignition. The excite wire on the accessories side still monitors charge load needs.

 

Nice thanks for the info man. I don't have an accessory post just a battery, coil and gauge. But the wire came with an idiot light lol appreciate you man!

 

@Kerrynzl

Haste to bug you man but I just realized that I left out the fact that I use a push button start on the 40 ford. Does that change anything?

 

Just did one. It’s the small brown wire at the plug. (Note, I made that wire brown)

 

Thanks!!

I understand that I should be wiring the wire to the "Coil" post on the key switch but do you know if the push button start changes anything in the wiring set up?

 

I’ve never wired one that way and never used the device you posted. I’ve alway’s wired from ignition switches acc. terminal to a generator light then from light to alternator. But you did say you have an inline diode so it should work. Just not how I like doing it.

 

By the way. What’s this called? I’d like to understand it better as to what the gauge terminal is all about.

 

That is the back of the key switch on the 40 ford. The key turns, there is a lever switch to turn the power on and then you push the start button.

 

Ok, I looked up 40 wiring diagram. Got it.

“Gage” terminal could be viewed as being equal to ACC. terminal like that of later ignition switches.

 

I save every usable alternator wiring diagram I find on the net on my photobucket album in the alternator wiring album.
This is one diagram That is easy to follow.

In the long run they all show the same thing and the two drawn diagrams just show it a tad different.


This is pretty well w hat Johnny Gee did on his.


This is the first image of adding an internal regulator alternator I ever came upon and have used it several times and shared it who knows how many times.
URL=https://hosting.photobucket.com/albums/w71/mr48chev/ALTERNATOR WIRING DIAGRAMS/.highres/AlternatorHarness31.jpg?width=960&height=720&fit=bounds][/URL]

 

Just connect it to the Ignition circuit it needs to be switchable [so it's off when the ignition is off]

Your starter button [dash mounted] can be connected 2 methods
1: from the ignition to the button, then button to the starter [the starter button is dead with the ignition off]
Or
2: from the battery 12v source [this is handy for bumping the engine over without starting] we do this on race cars!

 

Thanks dude. I checked. Looks like the ignition post or "coil" goes to the button and then the button goes to solenoid.

So if I just run it to the ignition post on the key switch I'll be ok? No need to worry about the actual start button?

 

Ok so I can just treat the gage post as the accessory post and just connect the exciter there?

 

A lot of them are internally bridged [inside the switch [it is just an extra terminal]
If you put a multimeter across both terminals with the ignition off there is continuity

On a Tri-5 Chevy you can hot-wire them at the fuse box [from 12v continuous to Acc]

Is your switch 2 or 3 position [OFF / ON or OFF / ACC /ON]
Check the switch with a multimeter on OHM's with the ignition OFF and see if there is continuity between both terminals.
The Multimeter should read zero.

If that is the case, you can use either/or terminal for IGN, Exciter, Gauges etc

 

You're OK
That is the safest method, the starter can't be "bumped" with the ignition off.

On race cars we do the starter live so we can bump the engine [setting timing etc in the paddock]

 

I’ve never had that switch in my hands. Like said above, run a multi meter across the terminals to see how switch exactly works.

 

Awesome thanks you so much man. I'm trying my best not to screw anything up... but there's quite a learning curve haha

 

Johnny, you do beautiful work! I have wired several 10 SI alternators the way you did with the sense wire to the output terminal. Is there any advantage to running the sense wire all the way to the starter?

 

Actually it should be under the dash where load is distributed. I’m lazy and this has worked well for me on non ac or power optioned cars.