1961 88 Overcharging, with 2 new voltage regulators tried

zooooot

New member
Sep 19, 2020
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Hey everyone. I'm having a charging issue. I got my generator rebuilt recently. It was working okay and I installed a new voltage regulator. Both of them have it overcharging to close to 17 volts (I shut it off right away) at the start. Are there any other things to look for? I wouldn't think two brand new regulators would be bad! Grounds are all nice and clean, new wiring leading to the regulator. Everything is clean and tidy and wired as it should. I also polarized the regulators.
 

Olds 307 and 403

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Oct 4, 2018
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Melville, Saskatchewan
It could be in the alternator itself unfortunately. I had a chrome Chinese 100 amp 10SI chrome alternator overcharge from day one. A new regulator did nothing. I would get a known good alternator, a spare is never bad. The chance of two bad regulators is small.
 
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zooooot

New member
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Sep 19, 2020
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I was going to take the generator/regulator off the car, which I did... and as I was inspecting the regulator, I noticed that one of the bushings was on backwards. The instructions tell you to do it I certain way, I suppose grounding? So it was backwards and towards the body. I put it all back together, tried it again. At high idle, it was at 14.55 volts, holding steady, until it ran out of gas. So, I suppose it was my own negligence that caused the issue.
 
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Rocketman269V

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Feb 26, 2020
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It could be in the alternator itself unfortunately. I had a chrome Chinese 100 amp 10SI chrome alternator overcharge from day one. A new regulator did nothing. I would get a known good alternator, a spare is never bad. The chance of two bad regulators is small.
I guess that you didn't notice that he has a '61, which has a generator.:oops:
 

Olds 307 and 403

Active member
Oct 4, 2018
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Melville, Saskatchewan
Same difference😁. Go back a few years, then you run into the 6 and 12 V change in systems as well. I wasn't sure what the first year GM used alternators. Glad he got it fixed.
 

Intragration

Member
Apr 2, 2019
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Chicago
Just out of curiosity, does anyone know of a way to TEST a generator/alternator that uses an external voltage regulator, as in, a spin test? Only place I know of is at certain auto parts stores, but they claimed to only test internally-regulated alternators. One of my cars has an external regulator, and I ended up troubleshooting by replacing both parts...which turned out not to be the problem.
 
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Olds 307 and 403

Active member
Oct 4, 2018
657
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Melville, Saskatchewan
I did this years ago on an old machine in college, Sun maybe. It basically tested amp output. It was a 65 amp Dodge alternator with the external voltage regulator. I have been fortunate, my 70S has charged fine with old external regulator and 10DN alternator. I did upgrade to a 70 amp from the 40 or 50 amp reman the previous owner put on it. I saw corrosion issues cause no charging on the Dodge set ups. I would look wiring and especially the grounds.
 
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Intragration

Member
Apr 2, 2019
61
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Chicago
Sun had all the good machines. I still want one of their distributor testers. You're absolutely right, I figured it out at the time, and it turned out to be a bad negative battery terminal. I have experienced some of the weirdest issues, always related to bad grounds, or other forms of high-resistance. I once had a...I can't remember if it was a fuse holder or a fusible link. But there was something with it, where it wasn't making good contact, and it was carrying quite a bit of current. The damn thing melted into a dripping mess. I was able to do a postmortem and found the bad contact. Replaced it with a good one, and the problem was solved. I can see why electrical problems can be so vexing though. A little bit of wear, corrosion, and vibration in some hidden, out-of-the-way connector is all it takes.
 
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