I have two alternators, one worn-out from my '72 that looks like what's in the chassis manual, and another type on my '71 motor (currently in the car) that doesn't look the same. When I got the motor only the red wire was attached to the + terminal on the alternator, while the standard white and blue wires were hanging loose close to the alternator. Additionally, the in-dash genny light didn't work and there had been added a secondary voltage regulator alongside the standard unit by the previous owner, for some reason.

I've experienced flukes and spikes in voltage when the car's running, and I suspect the lack of proper wiring is to blame, but I can't tell which connector on the '71 generator should connect to the white and blue wires respectively.

Given that the add-on regulator hooked up to the genny light wire and the rear defog switch and power supply, and the rear defog is no longer attached to the rear window, I took the liberty of removing it and plugging the genny light wire back into the original voltage regulator. Sounds okay, right?

Pictures of the two alternators and the aftermarket regulator:
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Rebuild your original one. The one that was on it is industrial or farm equipment. The aftermarket reg looks like a relay that shouldn't be on there.

 

It isn't very clear from the picture, but the one that was on the '71 says "AC Delco, made in France." All the 55A from my '72 needs is new brushes (coals?), which I should be able to pick up easily.

I wised up and asked my father about the wiring, and he deduced enough to tell me that the white wire should connect to the negative lead and the blue should connect to the "D +" lead, which means I can get driving while I rebuild the '72 genny.

Good to know it wasn't a crazy call to remove the aftermarket gizno.

 

I wouldn't use this alt at all unless I knew about the innards and how it works. D+ is usually for the indicator lite. This is telling me this may be an internal reg in this alt, but not necessarily so. If there are no other connections to the alt, it will be an internal regulated alt and you should put the brown wire you had at the reg to the D+ post and a battery to the B+ post. The ground will be made thru the alt case to the mounting and no ground wire is necessary. The white wire is not a ground wire. So do not use either the blue or white wire in the original alt plug. Only connect B+ to battery lead and the reg brown wire to the D+. I think that will work if the alt has not been damaged already. let me know.

 

I took pictures of the inside of this alt, hold on while I upload.

 

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There ya go. The '72 (not depicted) has an internal transistor.

 

It is internal. Hook it up like I said B+ and D+ to brown wire.

 

Brown wire being dash indicator, yes? If so, I'll make that happen. This makes getting HEI set up a lot easier.

 

correct

 

Splendid! Taking the ext. regulator out of the equation should stop the flicker I sometimes see in my lights.

I appreciate the help and advice - the more you learn...

 

Since the sense wire is internally connected to the battery post, this may work even without the brown D+ indicator connected. It will perform like a 1 wire alt that way. You should be good now.

 

Seff let me know how it goes. The 72 does not have an internal regulator. It also has no transistor.

 

I apologize for the quality of the picture, but this is the inside of '72 alternator. Due to the orientation of the plugs I deduced that it's externally regulated, but I was under the impression that the small round thingy in the bottom right corner with one wire was a transistor? Pardon my ignorance, I'm very much in the learning stage still.

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It is a capacitor. Did the French alt work? The 72 is external. It looks like you got every minute possible out of those brushes.

 

Ah, then consider me educated.

I never drove the '72, it came with a cracked frame and a completely rusted engine, and was driven until at least 2004 - so the worn brushes are understandable.

I'm not putting the french alt on until I can get myself a new fanbelt, and the car parts place over here isn't open on weekends.

 

Dummy me. I didn't notice you were from Denmark. Now I see why you had that other alt on there.

 

Happens all the time, it isn't just you. Finding parts has been an adventure at times. The '71 donor car had some kind of tag in French on the pass. side wheel well, so I suspect it's driven in France or Belgium at some point.

 

Unplugging the external regulator, connecting the brown and blue at the plug, and attaching the blue wire to the D+ terminal made my genny light work like it should, and I certainly don't seem to have less power. Will have to wait until a day I'm at the workshop in the dark to see if the lights flicker.

Thanks. :P