GM 1 Wire alternator

[freds40]

I'm guessing the info is out there but I haven't gotten the right search words apparently.

First question is on the pulley. I've heard the F-motor alt. pulley will bolt onto the GM alternator. Is this true? If so, is it a pretty small diameter so this thing will have decent output at low RPMs?

As for wiring of it, I know the Battery cable goes......well to the battery and I know this will make the alt. work just fine. But with the other 2 factory wires, what needs to be done there? I'm guessing one is for the charge lamp but I thought I heard once it can only use 3 amps or something. And also what of the other wire?

Any help is much appreciated as I'm looking to get my winch installed, as well as my CB and radio.

 

[ntsqd]

With the one-wire regulator you shouldn't need to do anything with the other wires/terminals.

One-Wire alts are, obviously, self-exciting. They usually take a little RPM to get started. You may find that you have to give the throttle a whack in order for the alt to start working on hot re-starts. Once going it should be fine at normal idle speed.
Were it me I'd put in the other wires needed just in case you have to swap in a 'normal' alternator.

EDIT: Sorry, no idea on the pulley interchangeability. I can tell you that I put the pulley of my '84 Mini's alt on a Delco CS130. The spacing was different than the stock pulley, but the bore & shaft sizes were the same.

 

[freds40]

Yeah I've actually run this alt before so I know about that little quirk. I thought I had read somewhere that if one of the other wires wasn't tied in somewhere that the charge light would be constantly on. Curious if this is true and if so, can it take 12 volts or does it need to be knocked down.

And of course that whole pulley thing.

 

[ntsqd]

Not as far as I'm aware of. With a one wire wired with only one wire the charge light won't do anything unless the wire from it gets accidentally grounded. [say that 3X really fast! ]

 

[lehiguy]

I've been running a one-wire for six years with no issues. Just put the extra wires somewhere where they can't ground out or hurt anything. My charge light never came on, but I suspect that it just plain doesn't work. No matter, it's a Land Cruiser and has ACTUAL GAUGES!!! Eventually I removed all the relays in the passenger footwell to make room for my TBI computer. One thing about the later GM alternators, and I think it's true of all GM, V8 alternators that use a serpentine belt; they tend to fry the front bearings. I have been considering going to an older style (bigger bearings) and modifying my serpentine bracket to accomodate it. I keep a spare alt. in my garage and when I hear it starting to make noise, I put the other on and replace the bearing in the noisy unit and on it goes. I have done this about every 25k miles on the average. Since the parts are virtually free, I don't wory about it so much. Soldering in the self-exciting regulator is the hardest part, so I reuse the same rear half of the alternator when I rebuild.

 

[zebrabeefj40]

I have used the F/2F alternator pulley on Delco alternators with success. I didn't notice any RPM related charging issues. I can't help with the one wire stuff.

Nick

 

[lehiguy]

One more thing, it does start charging immediately. I have never noticed any sort of lag. I have heard that the one-wire arrangement doesn't put out as many amps, but I have never seen proof, and since a well-fed hamster on a wheel puts out more amps than the stock alternator, it's a moot point.

 

[ntsqd]

I have read that the Amps Output vs. RPM curve of a one wire is less than a std. configuration alternator at low stator speeds, but I have never seen a graph from a reputable source that showed this to be true. I would expect there to be a tiny loss right at the bottom end of the curve due to the self-excitation consuming a tiny amount of power, but even engine idle speed should be above this stator RPM.

[hijack]I can't recall ever seeing the word "moot" correctly spelled, and used, on any forum except here. Most often they type "mute". Where's the :thumbs-up: smiley?[/hijack]

 

[freds40]

Had a spare 2F alt. and the pulley swapped over. I did use a washer for spacing as the recess on the fan does not match the shoulder on the pulley so that aill keep from crushing the fan.

Now, if both my girls would be well for 1 day, I could actually throw this thing on.

 

[freds40]

Quick follow up. Got it installed today. It took all of an hour and a half start to finish. 2F pulley bolted right up. I added a spacer under the pulley as the relief on the fan is smaller than the shoulder on the pulley. Without a spacer you'd crush the fan when tightening.
I just worried about the alt.-battery cable and after starting it up and running, no charge light. Looking forward to adding some more electronic stuff now.

Super easy install.

My install info if interested.


https://forum.ih8mud.com/60-series-wagons/221512-freds40-builds-60-a-14.html

 

[ntsqd]

I like simple mods!

I'd suggest some adhesive lined heat shrink jumping the gap from the insulation to the terminals. If it won't fit over the terminals (common issue) then I'd suggest getting some of the 3M "Self Fusing" electrical tape and using it there.

Two things happen there. Water gets in between the wire strands at such an opening in the insulation and causes corrosion that slowly reduces the alt's ability to charge the battery(ies). It also acts as a strain relief to keep the strands from breaking over the edge of the terminal's barrel. That gives the same result as the first problem.

 

[freds40]

yup, not sure why I didn't do these. I had wrapped all the cables on my 40. I think I must have forgot.

 

[ntsqd]

yup, not sure why I didn't do these. I had wrapped all the cables on my 40. I think I must have forgot.

I know that scene: [Looks down at doubly crimped cable lacking heat shrink] "Aw, shiite!!!!"

 

[jvazquez53]

Quick follow up. Got it installed today. It took all of an hour and a half start to finish. 2F pulley bolted right up. I added a spacer under the pulley as the relief on the fan is smaller than the shoulder on the pulley. Without a spacer you'd crush the fan when tightening.
I just worried about the alt.-battery cable and after starting it up and running, no charge light. Looking forward to adding some more electronic stuff now.

Super easy install.

My install info if interested.


https://forum.ih8mud.com/60-series-wagons/221512-freds40-builds-60-a-14.html

I always thought that something was wrong with my GM alternator because every time I start the truck, the alternator needs a "kick" from the throttle to get it going.
That red wire is all you need??? How much these alternators go for?

 

[ntsqd]

There is nothing wrong with the alternator needing a"kick" so long as it stays charging after it has returned to a normal idle speed. It just means that the regulator won't start charging until some minimum RPM is reached that is above your idle speed. A different regulator may or may not cure that. A smaller alternator pulley would speed up the alternator and put it closer to the minimum speed or faster than it. For it to sit there not charging until you drive away isn't a big deal unless you plan to do that for a very long time.

 

[jvazquez53]

There is nothing wrong with the alternator needing a"kick" so long as it stays charging after it has returned to a normal idle speed. It just means that the regulator won't start charging until some minimum RPM is reached that is above your idle speed. A different regulator may or may not cure that. A smaller alternator pulley would speed up the alternator and put it closer to the minimum speed or faster than it. For it to sit there not charging until you drive away isn't a big deal unless you plan to do that for a very long time.

Ok... that takes care of what I thought was a problem (kick), now on those one wire alternators what's the biggest one (output amperage) you can get?