[Ironbo]

Guru's of all that is Chevelle... I need your help please. I recently bought a 1971 Chevelle. Had the standard dash (idiot ALT light). I just put a new Autometer volt gauge a was really surprised. The voltage (while driving or idling) would swing from 12 volts to 18 volts every few minutes. I put my volt meter on and verified that was accurate. Thanks to you guys I prevously discovered that the engine was from a 1988 Chevy 2500. So I replaced the altenator (identical to the one that was installed Duralast 7122) Which was for a 1988 Chevy 2500. But still had volt swings. Upon further investigation I discovered that this particulatar altenator has a "built in" voltage regulator. I also discovered that the original voltage regulator was still installed and wired in.
Question; Is this what is causing the huge volt swings (two voltage regulators battling it out)? What can I do to correct this?
Thank you!!

 

[AXEMAN39]

You should only have one voltage regulator. And by running two you are risking damaging your whole electrical system and it could be a fire hazard! I just recently had a voltage regulator go bad in my elCamino I was lucky, it not only blew almost every light bulb in the car but it also fried my tach. At least my car didn't burn to the ground!

 

[Rick T]

do yourself a favor and just use the alternator that has an internal regulator. It is VERY easy to adapt your old chevelle to this alternator. Just take out the old regulator (should be behind drivers side headlights?). The only wire you have to run to the alternator is a think 12volt wire that runs right to the battery (the existing wire there should be fine). Then, theres also a plus that goes into the alternator that has 2 wires. Find out which one is the "field" wire (will say F next to it) and connect it to that same 12v wire from before.

Very easy.

Or get a "1 wire alternator", just needs a 12 volt wire and thats it

 

[Ironbo]

So Rick, just so that I understand, unplug the 4 wire plug from the voltage regulator (which as you stated is behind the drivers side headlight) then land a new wire on the altenator from the battery along with the wire on the (F) Field terminal of the Alt.???? Is that all??

 

[dude67]

This might help

 

[Ironbo]

Dude, THANKS!!!!!!!!

 

[Schurkey]

Some of the replies that you've gotten are assuming you are using the older SI-series internally-regulated alternator. You aren't, you're using the CS-series.

I have never converted to a CS-series; primarily because the CS-130 is a total piece of junk infamous for locking up the rear bearing. I've been forced to replace several CS-130 alternators on my vehicles; all of them because of rear bearing failure.

HOWEVER, I'm told that they're better now than they used to be; and if the engine compartment isn't cramped so they get adequate air flow, supposedly they aren't too bad.

At any rate, there's a Tech Reference that deals with installing a CS-series alternator on the older cars:

http://www.chevelles.com/techref/ftecref14.html

 

[Ironbo]

Thanks Bro!

 

[Augustboy2009]

I have the CS130 alternator on my 72 elco. Once my battery is charged the alternator "F" wire starts frying the wiring harness!!!!!!!!

Does this mean the internal regulator in the alternator is bad?

The volt gauge reads 13.8 volts then when the battery is charged completely that's when the wire starts to fry that's hooked up to my harness.

HELP!!