Hi everyone,

Ok, new problem with my 70 Elky. The old voltage regulator seemed to have puked causing an over charging of the battery at a whopping 16 volts.! ! I picked up a new voltage regulator from Pep Boys and replaced it now charging the battery at low 12's. The other day the battery wouldnt start the car so I jumped it with one of those booster boxes and then checked the voltage coming from the hot wire on the back of the alternator figuring the voltage regulator was just replaced and should be ok. The voltage at the stud on the back of the alternator was only 11.07 v which obviously wasnt charging the battery. I brought the alt. to a local starter / alternator rebuilder who rebuilt the thing and said there was a flat washer that was inside the alt which broke one of the wires on the strator field. Now I reinstalled it and it is charging at only 12.28 volts. To me that seems to be low so I called him back and said what was happening. He said that the voltage reg. is probably bad again from the washer shorting out inside the alternator. Is this right? How can I rule out the alt. or voltage reg to be the problem?

Any help would be appreciated.

Thanks,

Brian

Brian,
I had the same problem a few months ago, I went through 3 voltage regulators! I guess they have the tendancy of crapping out pretty easily. I ended up doing the "cs SI" conversion with a 105 amp alternator which is self regulated. Pretty easy convert actually with the help of everyone on here! Not sure if you'd want to can the original setup, but for my 2 cents, it's just what I needed.... hope you get it fixed soon. :D

Originally posted by pnutkemist:
Brian,
I had the same problem a few months ago, I went through 3 voltage regulators! I guess they have the tendancy of crapping out pretty easily. I ended up doing the "cs SI" conversion with a 105 amp alternator which is self regulated. Pretty easy convert actually with the help of everyone on here! Not sure if you'd want to can the original setup, but for my 2 cents, it's just what I needed.... hope you get it fixed soon. :D pnutkemist,

This car is all original and I want to make it concourse worthy if it is not already. With that being said, I unfortunatly need to keep it all original so I guess I will be replacing the voltage regulator again. Thanks for the insight about the poor quality voltage regulators though. Just curious, were yours made by Delco or some other auto parts stores?

Here's my standard response to this. Hopefully with this you can figure out what is happening.

I'll try to provide a simplified explanation of how the externally regulated alternator and regulator work here. This explanation starts from a parked car with engine off state.

The brown #4 wire is connected through the light bulb to 12V whenever the key is in the ON position. The other end goes through a set of points in the regulator and then out the F terminal to the field winding in the alternator. So some current begins flowing in the field winding from this connection. The little bit of current flowing produces a weak magnet field in the alternator and also lights the bulb.

When you then start the car, the weak magnetic field from above begins rotating which makes the alternator producing a little bit of voltage. This voltage is fed from the alternator to the regulator on the white #2 wire. This wire connects to a coil in the regulator and turns on a contact when the voltage goes above 3.2V.

Once the contact turns on in the regulator the #3 and #4 terminals are connected together. Terminal #3 is battery power so this puts battery power on both sides of the bulb and turns it off. This means the brown #4 wire should go to +12V. Also, this connects the field terminal right to battery power but still going through the points.

When the battery voltage goes above a set level, the F terminal is disconnected from the battery power by the points I kept mentioning. Then the voltage drops and the points close again. This on-off cycling happens rapidly and is how the voltage gets regulated.

From the above (KOEO = key on engine off and KOER = key on engine running).
F terminal - KOEO = #4 slight voltage KOER = 9-12V typically
#2 terminal - KOEO = 0V KOER = >3.2V
#3 terminal - KOEO = 12V KOER = 12V
#4 terminal - KOEO = F slight voltage KOER = 12V

By 12V above I mean battery voltage, which may be 12V when engine is off but should be 14V when engine is running.

Check the brown #4 wire by grounding it at the regulator. When grounded the light should come on. If you don't have a light then skip this test. Test this with the connector off the regulator.

Jumper the blue wire F terminal to the battery right at the alternator connector. This should make it crank out 16+ volts. If it passes this test, jumper wire the brown wire (#4 of the regulator connector) to the same F terminal and you should be able to measure >3.2 volts on the other alternator terminal. If these tests pass, it is in your regulator or the wiring to the regulator.

If you know for sure the wiring is good then try getting another regulator. The first one I purchased wasn't the right one but it looked correct and fit right. At least thats what the parts guy though but at any rate it was either wrong or didn't work.

Peter

Ok, someone help me out here my memory has faded on this. If you unplug the regulator you can jump 2 wires on the plug and the altenator should show if it's chargeing to it's fullest capacity. If it does, the reg. is bad.

OOPS.. I think Peter just said that!

The ones I tried were the ones they sell at Kragen, I dont recall which brand they were, red and white box I think :D But they werent very expensive. I hope you get it up soon, wiring is one of the most frustrating things to work with it kills me everytime :mad:

Originally posted by Peter F.:

Check the brown #4 wire by grounding it at the regulator. When grounded the light should come on. If you don't have a light then skip this test. Test this with the connector off the regulator.

Jumper the blue wire F terminal to the battery right at the alternator connector. This should make it crank out 16+ volts. If it passes this test, jumper wire the brown wire (#4 of the regulator connector) to the same F terminal and you should be able to measure >3.2 volts on the other alternator terminal. If these tests pass, it is in your regulator or the wiring to the regulator.

If you know for sure the wiring is good then try getting another regulator. The first one I purchased wasn't the right one but it looked correct and fit right. At least thats what the parts guy though but at any rate it was either wrong or didn't work.

Peter Peter,

I dont have a light that I am aware of as it has the SS package. If I do have a light, it must be burned out since I did not see one. As to the other testing, I jumped the blue F wire to pos. side of battery and immediately the voltage started rising 12,13,14, etc. So that tested out fine. The other test was good also showing about 6 v. on that test. I ordered a new regulator repro one from ground up and should hopefully have it in a day or so. I will keep everyone posted as to how it goes. I also pulled the cover off the aftermarket one to see if the voltage regulator part was ajustable which it wasnt. Oh well, Im sure the one from Ground Up should be fine as I have had very few probs with their stuff.