SBC alternator wiring help (1 Viewer)

[sblesse]

I've searched the forum but I'm stuck. Here's the background.
The PO did an SBC conversion but to say that it was done half ass is an understatement. I'm slowly picking away at all of the problems. I replaced the battery stand and a couple of wires from the alternator came out of there connectors. After hooking everything back up my I almost got stranded on the side of the road when my alternator quit(I thought). I took the alt in and it checked out ok. From what I can tell it is an Ac Delco 3 wire alt. It had only one wire from the plug spliced into the wire off of the lug in the back. I have since simplified this and jumped the wire to the lug as you can see in the pic. The wire from the lug runs back and and hooks into the starter.

Couple of questions.....1. Is the other pic the regulator? It is still connected. If the regulator went bad would it cause my problems even if the alt has a built in regulator. Should I just unplug the stock regulator?

2. Should I disconnect the alt from the starter and just run it straight to the battery?

Hopefully that is as clear as mud. Fire away.

 

[bikersmurf]

1st pic is the stock external regulator. It's no longer being used.

2nd pic. Gm alternator. The third wire is for an idiot light. The battery is connected directly the the bolt on the back of the alternator. The others... I don't remember.

 

[Mach Schnell]

Yea, the battery will run directly to it, if Im not mistaken....Ill have to go investigate to make sure.

 

[mightyjoetongue]

It looks like you are missing your 12v supply wire. That would go onto the lower terminal, below the loop for the regulator. I would try running a fused 12v feed to that terminal and you should be good to go.

 

[sblesse]

If my stock regulator was still hooked up and failed would it cause the battery drain that I experienced? I have a suspicion that it is still hooked up because the charging on this 40 has always been very quirky.

 

[pbgbottle]

here a copy and paste for what i did to get rid of the voltage regulator

TLCA's Toyota Trails: Tech Exchange
Alternator Swap (Toyota to GM)

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I have a Chevy 350 in my 78 FJ40, but am running the stock Toyota alternator. It is getting tired, and I want to replace it with a GM alternator. I have all the necessary mounting hardware, but was wondering if you could shed some light on the wiring. The Toyota alternator uses an external regulator, while the GM uses an internal one. Could you describe how to marry the two?

Thanks in advance.


Since you have all the mounting brackets, the installation will be pretty straightforward...

Note: The following instructions, when initially published, had incorrectly switched the connections for the #1 and #2 terminals. This has been corrected. Thanks to Michael Reardon for reporting the inaccuracy, and to Mark Whatley for providing the corrections.

Remove the Toyota alternator and position the GM alternator in place (you may need to use a GM positioning arm). Note that the GM unit has three electrical connection terminals, labeled Bat, #1 and #2.
Attach the 'large white with blue stripe' Toyota wire to the Bat terminal of the GM alternator. The other two Toyota wires, 'white with green stripe' and 'white with black stripe', are no longer needed (but see step 5).
Make a jumper wire with a ring terminal on one end and a female spade terminal on the other. Use this wire to jump (connect) the Bat and #2 terminals.
Disconnect (unplug) the Toyota regulator, which should be on the firewall below the clutch master cylinder. The Toyota regulator will no longer be needed, so you could take it off the vehicle and save a little weight (all 6 ounces).
Now comes the tricky part, as you have options. The 'black with yellow stripe' wire at the Toyota regulator connector is an ignition key controlled 'hot' wire coming from the engine fuse in the fuse box. This hot wire must be connected to the GM alternator #1 terminal. The options involve how you want to do this:
run a wire from the 'black with yellow stripe' wire to the #1 terminal.
run a wire from the engine fuse to the #1 terminal.
connect the 'black with yellow stripe' wire to the now unused 'white with green stripe' wire at the regulator connector and then connect the 'white with green stripe' wire at the alternator to the #1 terminal.
Well, that should do it. Happy charging!

 

[sblesse]

Thanks everybody. Problem fixed. I had jumped from the #1 to the bat lug when it should have been the #2 that was jumped across.