Tech secret found for ailing Voltage Regulators, early style.

[joeblow]

Well I think I have a tech secret to share with the group. If you have an early car like me with the all metal VR this might work for you too.

First off I am in Costa Rica, which means doing the part replacement method of troubleshooting adds 10-15 days a part to get here so 'real' troubleshooting is really the only way to go.

In my case my car was overcharging which in many senses is a good thing because it pretty much rules out a bad alternator.

My overcharge was also not maxed out meaning I was getting some regulation. Here are my numbers:
Nice new battery 12.8V standing (small Deka unit by the way).
Idle warmed up 15.5V
3000 RPMs 16V and that was the max it would go.
Then with heavy load (headlights, wipers, fresh air fan and such) 14.5V, still too high.

So even though it was not maxing out at say 19V it was definitely too high. So I decided to 2X check my wiring as this is a fresh restoration and a lot has changed. Wiring was fine and nice and clean as I just did all of this.

Next was to pull the VR and take a look inside. It was very clean looking but I gave it a good spray down with electrical contact cleaner anyway. I also took some 200 grit sandpaper and lightly sanded all the contact points (look just like points in the dizzy), top and bottom to make sure they were getting good contact. I then reassembled everything and tried again. Basically no change to say .25V lower.

So then I took the cover of the VR off again and fired up the car to see what was going on. The rocker was regulating but it seemed to struggle to get closed (off current). I used an insulated screwdriver to close the points and indeed the charge would stop. I also opened them and the charge would go way up.

So I have a working VR just out of range. So that was when I realized that the points are closed by an electromagnet which in this case was not pulling hard enough against the spring tension to close the charge. So I simply bent the tab which holds the spring (looks like it is designed to be adjustable). By slightly reducing the preloaded tension of the spring, I could vary the voltage output. With a little trial and error and nice needle nose pliers, I set it at 13.6V idle and 14.5 at 3000 RPMs.

I have tested this hot and cold several times today, with load and without, and it is now 100% A-OK! No guarantees how long this will last but I am running and so far so good.

If you have a similar issue but are undercharging you might need to do the opposite and add some preload to the spring. Hope this helps!!

[jmohn]

Sure, back in the "old days" cleaning and adjusting a regulator wasn't that unusual, some (most?) even had an adjusting screw (easier and more accurate than bending the tab with a needle-nose).

Jerry M
'78 SC

[joeblow]

I dug all over the forums and all I found was 'REPLACE' the VR nobody would crack it open and do any work on them. I hope this saves a few people some $$$.

[djdsc]

The last time I cracked open a VR was 1967 and it was on my '55 Chevy, yea I was 16 at the time. Basically did the same thing as you Joe. Good work on not just doing the plug and play and pay.