Voltage Regulator- Who makes a good one post Covid?

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ACME SS

ACME SS

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Recently my ECU fried on my AC which was annoying. Replaced and it works (I hope it still does, I should say). Then the next time I drove the car (71 Demon) the new Classic Instruments Tachometer and Speedometer would intermittently quit working at roughly the same time. So today while taking the car out for a test drive after finding NOTHING wrong with the wiring on the instruments, I get a text and pull over. As I'm sitting there, the Spal cooling fan suddenly gets louder and faster (engine rpm not changing) and I notice the tachometer quit. I quickly realize there is probably an over-voltage issue and return home ASAP and sure enough it reads 17.1 V ! Oh, and I may have missed a connector on my new stereo when I replaced the AC ECU but now my stereo is dead too! I don't like knocking people or stores but I purchased the VR in question at a store that may wear green on St. Patricks day...just saying.

Question: Are there any sources for OEM or pre-pandemic quality voltage regulators?

Thanks, Jerry
 
I see both older used units and NOS voltage regulators posted here from time to time. They might cost a little more than current autoparts store stuff but sometimes the peace of mind might be worth it
 
Not sure what brand you got at Oreillys, but if I was going to pick an affordable, bolt on and go VR, I wouldn't hesitate to go with a Standard Motor Products VR125
 
First thing to do before you start throwing money and parts at it is to do a bit of troubleshooting. Unplug the VR and see if the voltage drops. If not you likely have the green field wire brush or wire shorted to ground, causing "full charge."

Have you done anything lately that might have moved/ caused a short in the harness? Replaced the alternator?
 
67Dart273 said:
First thing to do before you start throwing money and parts at it is to do a bit of troubleshooting. Unplug the VR and see if the voltage drops. If not you likely have the green field wire brush or wire shorted to ground, causing "full charge."

Have you done anything lately that might have moved/ caused a short in the harness? Replaced the alternator?
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With the VR plugged in, it varies between 15-17VDC. When I unplug it, it quickly drops from around 13.5 to 12.5 and then slowly drops from there. I didn't do anything with the wiring or harness or alternator.

The reason I replaced the VR was that after I installed all new gauges which included a voltmeter, I noticed on the first drive that my voltage was dropping and so i drove home quickly and when I got in the garage it was around 7v and the engine quit. I had been charging it between drives up to that point cause I thought it wasn't being driven enough but having the gauge showed me that it wasn't charging. Also, when I removed the original, the back of it was overheated and liquid solder had almost worked its way to the surface. The replacement VR fixed the problem (not for long) and now it is the opposite issue in that it seems to be overcharging.
 
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Johnny Dart said:
Not sure what brand you got at Oreillys, but if I was going to pick an affordable, bolt on and go VR, I wouldn't hesitate to go with a Standard Motor Products VR125
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Yeah the day I realized it was dead I searched this site and saw there were issues with aftermarket VR's so I thought I would take a chance. I ended up getting the only one they had in stock which was their "master pro". I see they have the Standard Motor Proctucts and an AC Delco but they would have been special order at the time. I'm really hesitant now to buy one if it's the same as the master pro but in a different box... I see the SMP is a different color as is the AC Delco so I'm curious if there is a difference internally? I've only got 445 miles on the Master Pro voltage regulator...which is not saying much.
 
ACME SS said:
Yeah the day I realized it was dead I searched this site and saw there were issues with aftermarket VR's so I thought I would take a chance. I ended up getting the only one they had in stock which was their "master pro". I see they have the Standard Motor Proctucts and an AC Delco but they would have been special order at the time. I'm really hesitant now to buy one if it's the same as the master pro but in a different box... I see the SMP is a different color as is the AC Delco so I'm curious if there is a difference internally? I've only got 445 miles on the Master Pro voltage regulator...which is not saying much.
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Make damn sure the regulator case is well grounded to the firewall. New paint isn't good as well as loose sheet metal screws in old holes. Run a strap if you must. Have you tested the battery? Have any bad cables or loose connections?
 
ACME SS said:
With the VR plugged in, it varies between 15-17VDC. When I unplug it, it quickly drops from around 13.5 to 12.5 and then slowly drops from there. I didn't do anything with the wiring or harness or alternator.

The reason I replaced the VR was that after I installed all new gauges which included a voltmeter, I noticed on the first drive that my voltage was dropping and so i drove home quickly and when I got in the garage it was around 7v and the engine quit. I had been charging it between drives up to that point cause I thought it wasn't being driven enough but having the gauge showed me that it wasn't charging. Also, when I removed the original, the back of it was overheated and liquid solder had almost worked its way to the surface. The replacement VR fixed the problem (not for long) and now it is the opposite issue in that it seems to be overcharging.
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Two things. Make sure CERTAIN sure the VR is grounded, and that the IGN feed to the VR is "at battery." Here's how to check

With the key in "run" but engine stopped, access the closest electrical point to the VR IGN connector. This is likely the key feed to the ballast resistor. Hook one probe of your meter to that and stab the remaining one into the top of the PLUS post of the battery. You are hoping for a very low reading, the lower the better. If your read more than .3V (3/10 of one volt) you want to find out why

VR ground. Do this check first with all accessories off, and again with heater, lights, etc powered on. Run engine at fast idle to simulate "low to medium cruise." Stab one meter probe into the battery NEG post and the other into the mounting flange of the VR, hard, to stab through paint, rust, or chrome. Again you are hoping for a very small reading, zero is perfect

If those two readings are OK you have a bad VR. If you keep blowing up VR's you likely have a partially shorted field (the rotor) in the altlernator If you look through some of the shop manuals, there's a procedure in there to measure rotor current draw
 
Hey thanks so much @toolmanmike and @67Dart273 . I'll be out of town the next week and don't have time to check this stuff right now but I will for sure do these checks when I get back and before I change out the regulator. You guys are the best! I appreciate all the help!
 
So I am back in town and was able to put a ground wire from the VR bare metal case directly to ground, and then to the neg terminal on the battery and I still had high voltage.

Next, I purchased a NAPA VR. I installed it and made sure I had a good ground. With the new NAPA VR it is reading a steady 15.15v. The previous VR would vary with engine speed. Obviously it is regulating the voltage since it stays at 15.15v regardless of rpm (more or less) but isn't that a little on the high side??
 
ACME SS said:
So I am back in town and was able to put a ground wire from the VR bare metal case directly to ground, and then to the neg terminal on the battery and I still had high voltage.

Next, I purchased a NAPA VR. I installed it and made sure I had a good ground. With the new NAPA VR it is reading a steady 15.15v. The previous VR would vary with engine speed. Obviously it is regulating the voltage since it stays at 15.15v regardless of rpm (more or less) but isn't that a little on the high side??
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14.2 is what I like to see
 
So this reminds me of the time I owned a 72 Datsun which would burn points every 3K miles because the condensors were never quite right. They were either under or over capacitive as indicated by which contact would be pitted or have a build-up on it. With the VR, the last thing I want to do is keep buying VR's until I get one that is correct.

My thought was, would a possible fix be to install a variable resistor of high current capacity in series and adjust it until I get it where it should be and then replace it with an equivalent resistor of the same value?
 
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