Voltage issue at battery.

[jmbass98]

Car has sat for around 4+ months. The voltage at the alternator was a bit high beforehand (15.5-16.5 if I remember correctly), and it was something I intended to work on when I finished moving states, but the battery read normally (I can't remember the voltage regulator). I just got my car back and checked the voltage. Running, the battery was at 16.8~ volts and steadily climbing until I turned it off. The alternator was around 17-18v when I checked, which mirrored the FLD side of the voltage regulator. So I tried replacing the voltage regulator with a new unit (never used, sat in box for 6~ months). Both from either Layson's or YearOne, so they should be good functioning units. This time, the battery started at 14.4v and steadily climbed until I turned it off. The alternator was sitting at 16.2-16.5 and climbing. The FLD side of the voltage regulator was wildly jumping between 6-13v and started smoking.

If it means anything, there is some belt squeal at the alternator when I push the throttle. This was the case before, and weirdly, it would go away after the car warmed up. I haven't left the car on long enough to see if it still goes away because the voltages worry me.

Attaching pictures of the alternator. It's a roundback style from Layson's, 60 amp. I was told the second FLD didn't need a ground wire to the case if I removed the rubber grommet between the screw and the terminal, as that would ground itself to the case. Not sure if that is a culprit.

What should I be checking at this point to see what the culprit is? Unsure if it's visible from the pictures, but the left-most spacer for the alternator isn't flush with the block, so I'm not sure if I have the correct spacer in (it's a replacement kit), and if that's messing up the geometry of the belt (causing the squeal).

No ballast. Pertronix setup. Engine harness and battery cable are both new and never had cause for concern until today.

 

[pnora]

What is the voltage at the blue wire on the regulator? It should be aprox battery voltage or slightly less. Key can be on without the engine running to make this test.

 

[jmbass98]

Key on and engine off, blue wire side reads 11.9+ and battery positive reads 12.4.

 

[pnora]

Key on and engine off, blue wire side reads 11.9+ and battery positive reads 12.4.

Unplug the regulator and start the car. It should not be charging.

 

[toolmanmike]

Wow! Don't run that thing very long at that voltage. You can boil the battery and/or cause a wiring fire.

 

[dadsbee]

I spy a two field alternator in a single field wiring situation. The unused field spade is showing clearly in the picture... is it grounded to the case like it needs to be or still isolated?

 

[jmbass98]

It came with a rubber spacer on that extra field terminal. I was told by local alternator shop that if I remove that rubber spacer and the screw has contact with the terminal, it would act as a ground.

See picture on post #5: Alternator ground question., I made a thread about this a year ago. It seemed to function fine at the time, though like I said alternator was running slightly high (15.5-16.5v ish), but battery would be stable 13.8-14v at fast idle.

 

[jmbass98]

Unplug the regulator and start the car. It should not be charging.

Do I just unplug the blue side or FLD as well? Limited time to fiddle with it during the day, so just curious.

 

[jmbass98]

Was hoping nothing would break from just sitting there for 4-ish months, but I guess that's how these things go.

 

[pnora]

Do I just unplug the blue side or FLD as well? Limited time to fiddle with it during the day, so just curious.

Either one.

 

[jmbass98]

Either one.

Blue side unplugged. Lights off. Fast idle, alternator reads 12.1-2v. Battery reads 12.31 and slowly drains, not charging.

 

[pnora]

Blue side unplugged. Lights off. Fast idle, alternator reads 12.1-2v. Battery reads 12.31 and slowly drains, not charging.

Ok next with the engine running what is the voltage on the blue wire at the regulator. It again should be close to battery voltage. If it is then double check that the regulator has a good ground or add a temporary ground. If the grounds are good then it is the regulator.

 

[jmbass98]

Regulator has a good ground wire from bottom screw to top-left side of intake manifold. Should be no issue there. Blue side reads 15v and climbing, exactly same as battery positive. VR immediately smokes on start-up.

 

[pnora]

Regulator has a good ground wire from bottom screw to top-left side of intake manifold. Should be no issue there. Blue side reads 15v and climbing, exactly same as battery positive. VR immediately smokes on start-up.

You have done everything right as far as I can see or tell you. Just be sure on the ground even though you think it is ok. It surely seems like regulator.

 

[jmbass98]

Re-seated and re-tightened on both sides. Tried a new ground wire. Same issues. Not sure how else to test it, but I will do whatever's suggested.

What's a good, reliable replacement for the OE electromechanical style VR? Would like to avoid Chinese knock-offs from NAPA.

 

[jmbass98]

Strange to me that the first voltage regulator had similar issues, but with way higher readings. The second one lowered the readings, but still far too high and erratic. Like they are different degrees of broken. Hoping that it really is a simple fix like a new VR and not a myriad of issues.

 

[pnora]

Re-seated and re-tightened on both sides. Tried a new ground wire. Same issues. Not sure how else to test it, but I will do whatever's suggested.

What's a good, reliable replacement for the OE electromechanical style VR? Would like to avoid Chinese knock-offs from NAPA.

That always seems to be a crap shoot. A lot of guys use the style that has updated electronic controls. They look factory. Back in the day the manual showed you how to adjust the mechanical regulators. However that was fine if the regulator was capable of being adjusted. Most of the time it was bolt a new one on and go.

 

[toolmanmike]

I tried 2 or 3 electronic ones and went back to the old points style. It sounds like yours is grounded well. Mine wasn't. It boiled the battery and blew a bunch of light bulbs out. It was charging up over 17v.

 

[pnora]

Strange to me that the first voltage regulator had similar issues, but with way higher readings. The second one lowered the readings, but still far too high and erratic. Like they are different degrees of broken. Hoping that it really is a simple fix like a new VR and not a myriad of issues.

Right. But each changed voltage even though it was not right. I have seen in my lifetime maybe two alternators that had an internal failures. One was my own. It would charge just fine for days and all of a sudden overcharge. Final fix was the alternator. My buddy who owns a starter and alternator shop figured the field on the ground side was going to ground in the rotar and full fielding the alternator. Not the same design as yours as mine was the two wire field which has battery voltage on one brush and uses ground to control the charge rate on the other brush.

 

[jmbass98]

Jesus, lol. Good thing I had the where-with-all to check voltages the second the car arrived from shipping. I've dealt with many electrical issues with this car, so it's second nature at this point. Putting it on the road would've been very bad, I imagine.