SBC and Voltage Regulator (1 Viewer)

[Vandal FJ]

I have looked, search is my friend, but the answers elude me. Probably due to ignorance of the subject and complete info overload. Jan 1972 40 with a 1975 Chevy SBC from previous owner, and a brand new alternator (internally regulated). It would SEEM from the threads I've read that the voltage regulator on the firewall is not a necessary item? If so, I assume it would be by passed. I have no big problems, but battery and alternator just went out and replaced, so i'm covering bases. Thanks in advance.

 

[middlecalf]

Internally regulated alternator doesn't need a voltage regulator. If the regulator on your fender does something in addition to voltage regulating, then maybe it is needed. But not for voltage regulation.

 

[Vandal FJ]

That's what I was thinking. It has a wire running to it and I wasn't sure if it was necessary, or should have been bypassed.

 

[1Fine40]

Bypass it! You do not need it anymore with the internal VR. Been running mine like that for a very long time ..

 

[Vandal FJ]

Bypass it! You do not need it anymore with the internal VR. Been running mine like that for a very long time ..

So just in case somebody ELSE needs instructions How do you bypass it? It's probably more than just unplugging it? Mine runs into another large loom of wires, so not sure how to bypass. Thanks in advance!!

 

[Coolerman]

You have left out some important information.

Was the previous alternator on the truck (the one that went bad) internally regulated? If it was, you should not have to do anything but mount it and go. This is assuming the old system was charging in the first place before the alternator went bad.
If it was not internally regulated, you are going to need to do some wiring to make the new alternator work.
Need to know exactly what alternator you have in order to tell you what you would need to do.

 

[Vandal FJ]

It was internally regulated, I put the same exact alternator back on it. I took a look at the VR yesterday and it's still hooked up, from what I can tell. I am not confident in the PO's skills, as the distributor was in wrong, and it was a general mess. It just seems that it shouldn't still be hooked up, if the alternator is internally regulated? I found one of Jim's Downey instruction manuals, so that will help, but if you know the quick correct fix, that would be awesome. Alternator I bought below.

Duralast Remanufactured Alternator DL7127M

Shop for Duralast Remanufactured Alternator DL7127M with confidence at AutoZone.com. Parts are just part of what we do. Get yours online today and pick up in store.

www.autozone.com

 

[ToyotaMatt]

 

[Coolerman]

Well, if the PO had it working, and it is currently charging the battery, you can just leave it as it is. If it bothers you, then by all means remove the regulator as it is not needed for the new alternator. Some pics of how all this is currently wired would help.

 

[middlecalf]

Yeah I’d be concerned that the sensing function wasn’t happening with the VR wired to a one-wire IR alternator. I like my rigs to have a volt meter so I can see the voltage drop as the demand drops (to include charging).

 

[Coolerman]

Few people wire the internally regulated alternators correctly. The sense wire should connect to the White/Red wire from the fuse panel in order to correctly read the correct voltage level at the fuse panel. Most just jumper it to the battery to make it work.

 

[1Fine40]

I apologize for not getting back to you. I do work for a living still. I took a look last night in my mounds of paperwork for a wiring schematic and did not find what I was looking for. (Good thing it works!) I'll keep at it and see if I can find anything that might be helpful. I did this mod almost 20 years ago, so my memory of exactly what I did ain't too great!

 

[Vandal FJ]

I apologize for not getting back to you. I do work for a living still. I took a look last night in my mounds of paperwork for a wiring schematic and did not find what I was looking for. (Good thing it works!) I'll keep at it and see if I can find anything that might be helpful. I did this mod almost 20 years ago, so my memory of exactly what I did ain't too great!

No problem at all! Wasn't upset or worried, figured more people might chime in.

 

[Vandal FJ]

So the alternator and the VR. Still hooked up, and I am certain the VR needs to go.

 

[Vandal FJ]

Few people wire the internally regulated alternators correctly. The sense wire should connect to the White/Red wire from the fuse panel in order to correctly read the correct voltage level at the fuse panel. Most just jumper it to the battery to make it work.

I managed to find your write up on the subject! I am thinking I can solve this now?! This applies for my GM alternator, as far as deleting the VR is concerned?

Cruiser Wiring

 

[Vandal FJ]

Now that I am learning what to look for, I'm not sure the red and white wires on the alternator aren't backwards? Everything I have read says the port on the passenger side should jump back?

 

[Vandal FJ]

Update: I went out checked my battery. Dead. Brand new battery and alternator two weeks ago, and wouldn't start. So, I switched the 1 and 2 ports on my alternator to match the factory specs (the #2 jumps back to the post), THEN (per coolerman's write up) hooked the white/green wire at the F terminal of the VR to the IG terminal on the VR that has the white/red, jumped it with the truck, and it fired right up. Tested 13.8 volts at the battery. Went to turn it off and no dice. Kept running. Which I have seen happen on different youtube videos, etc.

The wire off the post of the alternator runs inside the loom to the cab and is Black with Blue stripe. Not original, I don't believe. I think straight to ignition? I'm betting it's to the ammeter. Not sure, will have to check that. Seems weird the post doesn't go straight to the battery. But as for the voltage back flow, after working the google on the internet machine, it seems I need a diode at the #1 wire hooked to the alternator? Like below?

Delco 10SI Alternator Adaptor Plug - The Brillman Company

#B3000-001, Delco 10SI Alternator Adaptor Plug Connects to the back of 10SI Delco alternators, such as B6001-002. Includes diode to prevent voltage feedback. Doesn’t work with 1-wire alternators.

brillman.com

Any thought would be appreciated. I realize I probably need to rewire the whole damn rig, as I am not confident in the original owners work at all, at this point!