Upgraded Voltage Regulator

[MrMoparCHP]

Jumper bypassing the regulator; Do you mean disconnect the blue wire from the VR and disconnect the green wire from the VR and jump them together?

You can do that, I have a piece of wire with alligator clips on each end and use it.
This will only be there for a few seconds, you could even use a piece of solid core wire with no clips just poke in between the connector and the reg housing. Again just a few second to see the voltage change.


Alan

 

[mgm1986]

Hugely helpful, I am so afraid of hooking up the wrong wires and causing even more problems or starting a fire. I will use the wire with alligator clips and check voltage and report back.

 

[MrMoparCHP]

Hugely helpful, I am so afraid of hooking up the wrong wires and causing even more problems or starting a fire. I will use the wire with alligator clips and check voltage and report back.

Again, only a few seconds, enough to see the voltage climb.

You should see the voltage climb about 0.1 volt a second.

Put the meter on the battery and it should be pretty steady +/- 0.2 volts.
Add the jumper and see if it climbs, +.5 to +1 should be more than enough.

Without the regulator the voltage will climb till the battery blows up, at what point? (more than a few volts, keep it under 15 and you should be fine)


Alan

 

[mgm1986]

I did as you suggested and confirmed that jumping blue to green while disconnected from the VR, voltage climbed as you described, about .1 p/second at 1500 rpm. So it would seem that indicates the wiring and alternator is good, right? I sanded and cleaned the firewall surface where the VR mounts. Still nothing. How in the world can all three VR's be bad (It actually wouldn't surprise me)!!??

Sounds like it may be time to upgrade to the new style VR and alternator.

On a side note, I connected a dewalt 18v battery to the VR and i get a .8 voltage drop. The battery puts out 17.4 volts and the VR is regulating it to 16.6 volts. 2 of 3 I have did this, the third appears to be shorted internally as there is continuity between the field and negative on the regulator itself so I got a spark when trying to connect the clips.

 

[stubs300]

Go to the bone yard and look for a newer Mopar with this type of regulator. http://www.jegs.com/i/Mopar-Performance/312/P3690731/10002/-1?parentProductId=747030

Any mid 70's mopar will work! This is the newer style electronic regulator. Grab the alternator off the same vehicle and as much of the wiring as you can, and wire it up as the diagram given on page 1 of this tread. I have never seen a Mopar with that vr706 regulator. These mid 70's alternator are more powerful, like 60-70 amp units compared to the 36 amp units like what you might have now? Ensure that the new alt. have 2 terminals along with the batt lug.

 

[Big_John]

This is funny, I've known quite a few that have used the VR706 regulator with good success.

Having more than one fail makes me wonder if there is some other issue that is causing the failure.

 

[bluefury361]

This is funny, I've known quite a few that have used the VR706 regulator with good success.

Having more than one fail makes me wonder if there is some other issue that is causing the failure.

I have them on all three of my cars and have never had a failure. I do want to upgrade my 69 300 to a later charging system though. Lots of power accessories is taxing the old system. This thread is very helpful.

 

[mgm1986]

I thought I gave an update on this over the weekend, I guess I never hit POST.

So Friday afternoon I took my old mechanical VR and one of the new VR706 to a local AC Delco automotive shop here in SJ. They were able to bench test them and both were bad. Shockingly, they had an old mechanical VR in stock for $12 which tested good on the bench and looked like it was in the original box from 1968! So I took it home, hooked it up and voila, charging!

The mechanic suggested the same as you guys that something is/was most likely causing the VR to go bad, it is highly unlikely all three VRs were bad out of the box. He suspected the alternator may be causing them to go bad.

At this point, I have a new battery, new 45 amp alternator and new mechanical VR. Time will tell if this is solved, the last VR lasted three weeks.

 

[MrMoparCHP]

There were some comments that were lost to the restore the other day.

The newer alternators have higher a "field current draw" the originals were 2.3 to 2.7 and the newer ones are 5.8 amps, double that of the originals. This is the current that I feel is frying the regulators not the charging current.

Those that have had good luck with these electronic regulator upgrades probably haven't changed their alternator recently. I'm not saying that you will have problems just that there have been a few people that have.

I have seen nothing in my situation or that reported by other to support it being a problem elsewhere in the system.

The upgrade to the 70+ style regulator solved my problem, done!


Alan

 

[mgm1986]

There were some comments that were lost to the restore the other day.

The newer alternators have higher a "field current draw" the originals were 2.3 to 2.7 and the newer ones are 5.8 amps, double that of the originals. This is the current that I feel is frying the regulators not the charging current.

Those that have had good luck with these electronic regulator upgrades probably haven't changed their alternator recently. I'm not saying that you will have problems just that there have been a few people that have.

I have seen nothing in my situation or that reported by other to support it being a problem elsewhere in the system.

The upgrade to the 70+ style regulator solved my problem, done!


Alan

Thanks, Alan! I am hoping to get through the rest of summer with the old style mechanical regulator. This winter she is getting tore down for a restore and I now have on my list to upgrade to the new style regulator as you and others suggested. I think your idea makes sense on the field current draw being double.

The new mechanical VR for $12 has been holding a fairly steady 14.2 on the highway and I do not have any flickering lights as I did with the old mechanical one. With a little luck this won't crop up again.