Generator to alternator questions......

[Roothawg]

I know this is a common question but I am having issues here.

Here is what I took from an old post.
I am stuck on step 4.
I am confused on what I need to do with the large post on the back of the alternator?? I suppose it goes to the positive side of the battery , but do I fuse it?

Also which post is which on the alternator? Mine has no markings and I already mounted it and it is sort of upside down, so it makes it hard to read.

I have a 63 amp GM Delco 3 wire. SI type.

Thanks for the help.
Root




Wiring hookups:

1. Disconnect the battery

2. Remove the #10 Yellow/Black wire from the "A" terminal on the voltage regulator and attach it to the "B" terminal. (It is OK to leave the "B" terminal connected to the circuit.)

3. Remove the Black/White band wire from the "F" terminal on the regulator and remove the 18 GA yellow/black wire from the
"A" terminal (there were two black/yellow wires on the "A" terminal). Take these two wires and connect them together. In summary, this should leave you with two 10 GA wires on the "B" terminal, two 18 GA wires connected together by themselves, and no wires on the "A" or "F" terminals.

4. At the alternator, attach the pigtail to the alternator (most pigtails have a large 12 GA, usually red wire and a small wire, usually white). You must make sure the larger wire is in the #2 ("F") slot on the alternator and attach an eyelet with a #12 size hole. Connect this wire along with the 10 GA yellow/black from the harness to the "BAT" terminal on the alternator.

5. Connect the 18 GA black/white band wire from the harness to the new pigtail small wire that goes to the #1 ("R") slot on the alternator.

6. The 18 GA black/red wire in the harness is a ground and can be connected to one of the case cover bolts. Run a 10 GA ground wire from the case ground to the frame to insure a solid ground connection.

7. Reattach the battery terminals.

[CDN.SD]

The correct plug should be easy to get at NAPA, or any place like that, and it will make the job much easier.

IIRC, the red wire on the plug can be attached directly to the large post on the alternator, but it's a little bit better if it's connected to an un-switched positive junction point, somewhere on the car. (It detects the system voltage, and if there are any losses in your wiring etc., connecting it away from the alternator will allow it to compensate for them.)

The white wire is for the idiot light, and IIRC, it's a fine guage yellow/black stripe wire on most Fords.

PS The wire from the large terminal doesn't get fused, but be sure that it is run in a way that it will never short out on you.

PPS From what I can make out from the instructions, the 2 10 ga wires he's telling you to connect together are the ones from the battery and the one that powers the car. They have to connect to the large stud on the alternator.

Hope that helps.

[Roothawg]

Here's what I have so far.


I connected everything up at the regulator as stated in step 2 and 3.

Now I went to the parts house and bought the plug.  It has a white wire on post 1 and a red wire on post 2.  These I haven't done anything with yet.  These are the variables I can't figure out. 

You stated that the white wire is for the idiot light, is that still the case now that I have told you the orientation of my plug? I would assume they are all the same?

I connected the black wire with a red stripe to the case ground.

I connected the big heavy 10 gauge wire to the main battery post.

So I am assuming that the red wire just jumpers to the hot battery post on the rear of the case?

[CDN.SD]

The standard color code on those plugs is that the white, usually lighter guage wire is for the idiot light, and the heavier red wire goes to either the output (Battery) lug on the back of the alternator, or to another positive connection point in the car. (your choice, it should work either way).

After re-reading his instructions several times, I think I've figured out that he's connectiong the 3 10GA. (One from battery, one from generator, one powering the car) wires together at the old regulator, and then using the output wire from the generator (Yellow/Black 10 GA.?) to connect to the output of the new alternator.

Does that make any sense to you with what you're seeing. Unfortunatly, I don't have a harness handy at the moment to check.

PS don't worry too much about the ground at the moment, they're rarely needed.

[Roothawg]

Well, unfortunately, both wires on my plug are the same size, that's why I am double checking.
It sounds like I shouldn't have to fabricate any new wires, just use existing ones.

I am hoping this all works, because I suck at electrical troubleshooting.

[CDN.SD]

Well, it's the standard color coding on them, but these days, with all of the imported stuff it's hard to be 100% sure of anything. (I had 2 motor mounts the other day that wouldn't even bolt to a 302 block!)

If you want to be 100% sure, Google a few places online for one wire GM alternator hookup, and see if you can find a consensus there, on which terminal is which, but keep in mind, that the net is just about as reliable as Chinese parts. 

[Ford Blue blood]

There in lies the problem....that Ford is rejecting the GM parts!!!!!

[CDN.SD]

Yeah, it's a few more wires, but I prefer using a first generation Ford alternator for upgrades.

The "new" external electronic regulators (Old style mount with electronics instead of relays) work well on them, and it's nice to be able to just jumper the right terminals and listen for an instant diagnosis.

[Ford Blue blood]

Putting in the older style Ford unit is really easy.  Only need to add one wire if you have an "idiot" light and the parts are really cheap.  You can rebuild one of those early alternators for 25 bucks....

[CDN.SD]

Here (hopefully) is a drawing I found on line somewhere that comes in handy. (Thanks to the original poster)

[Roothawg]

Thanks for all the help.  I actually started the car this weekend and the light works, and it charges.  I even disconnected the battery to verify that it would continue running. Everything appears to be working fine. Now to finish the air.

[suede57ford]

I think you have to have a resistor added to get the idiot light to work, as that is how it works on the mustangs etc.

I put a resistor inline with the light on my '57 bird with a ford alt, and it now works.

[canadian_ranchero]

Thanks for all the help.  I actually started the car this weekend and the light works, and it charges.  I even disconnected the battery to verify that it would continue running. Everything appears to be working fine. Now to finish the air.

the voltage spike you get when you disconnect the battery when it is running,is really hard on the diodes and could blow one. 

[Roothawg]

the voltage spike you get when you disconnect the battery when it is running,is really hard on the diodes and could blow one. 

I didn't.......it works?