Chevy Nova Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
164 Posts
Discussion Starter #1
Hello everyone. I have a 72 nova 307 / th350.

Here is my situation.

The prior owner claimed to have switched from an external regulated charging system to internal regulated.

When I looked under the hood, I did see the deleted external regulator box and the typical 3 wire internal regulated GM alternator.

After buying the car and driving it around, everything has run fine. The battery has been going dead lately. The prior owner did say the battery was weak and would need replacement.

Today, I started to remove the battery, but noticed the following: There is only 1 wire hooked from the alternator to the car. The large red charging wire. It looks like the typical 1 wire hook up. Nothing else is hooked up. No jumpers either to the plug where the exterternal box had plugged in at. I think he used a 1 wire hook up on a 3 wire alternator.

I would like to do this the correct way. I dont mind a 1 wire hook up. However, if this is a 3 wire alt, please help me dobthis correctly.

Please see pics and advise....

Thank you very much in advance
 

Attachments

·
Registered
Joined
·
164 Posts
Discussion Starter #3 (Edited)
No. Nothing is connected. Only the thick red positive wire to the battery is connected.

I volt tested it and it sure is charging fine. Im wondering if it is a 1 wire unit. The only thing is that It still has the other 2 wire ports (#1 and #2). They are not being used.

I had the battery load tested and it is bad.

I dont undeestand how this system is charging with only one wire. Any ideas?
 

·
Moderator
Joined
·
6,497 Posts
I would take the alternator off and have it tested and if it works then put it back on and buy the below parts to where no wires have to be cut:

https://www.opgi.com/chevelle/27555/



The above are adaptors to change over from the existing wiring on the car which is setup for an external regulator and an externally regulated alternator and then allows an internally regulated one to be put in it's place. If later you want to go back to all original, these adaptors can be removed and nothing is cut or spliced together.

If the alternator is broke, then buy another just like it with the internal regulator.

Jim
 

·
Registered
Joined
·
164 Posts
Discussion Starter #5
I appreciate the info Jim. That is a cool product. Unfortunately I already did the following modification in preparation for a 3 wire interally regulated set up. see picture.

My issue is not the alternator. It has been tested and works fine.

The battery was fault, but I replaced it earlier today.

The faulty battery simply put me in a position to notice that this alternator is fully operating in a 1 wire operation. Only the thick red wire to the post is hooked up and is charging just fine.

The issue I an having is that I do not understand how it is charging with 1 wire. This alternator is old and appears to be a 3 wire due to still having the #1 and #2 plugs (unused).

I was wondering if this could be a 1 wire alternator or a 3 wire operating as a one wire.
 

·
Moderator
Joined
·
6,497 Posts
I appreciate the info Jim. That is a cool product. Unfortunately I already did the following modification in preparation for a 3 wire internally regulated set up. see picture.

My issue is not the alternator. It has been tested and works fine.

The battery was fault, but I replaced it earlier today.

The faulty battery simply put me in a position to notice that this alternator is fully operating in a 1 wire operation. Only the thick red wire to the post is hooked up and is charging just fine.

The issue I an having is that I do not understand how it is charging with 1 wire. This alternator is old and appears to be a 3 wire due to still having the #1 and #2 plugs (unused).

I was wondering if this could be a 1 wire alternator or a 3 wire operating as a one wire.
The only three pictures I saw were the three in your original post. I didn't see any of the harness being modified for preparation for a three wire internally regulated setup.

With you wondering how the alternator is charging with a 1 wire, I wonder, even though the alternators case looks old, is someone might have modified the guts. I know through the years I have taken old radio's and modified the guts and externally it looks original but it is not.

With you saying it is charging, what are your voltages with the engine not running and then running ?.

I know recently I had an issue with my truck and the alternator was not working and I drove it probably 15 miles to a destination and it sat and restarted fine and then drove it another 20 miles back home and all of the lights seemed just fine but my battery is good and it's got a decent amount of reserve and the only reason I knew the alternator was not outputting was from the idiot light in the dash being on and the volt gauge also indash reading low. I also verified this with a reading from my Fluke meter. If I did not have the indash light working or the volt gauge, I would not have known the alternator was not working until probably many miles later when the battery would no longer be able to supply the needed power.

Jim
 

·
Moderator
Joined
·
6,497 Posts
Sorry Jim. Here it is. What I did...
I was wondering if I wasn't seeing it. :D

Basically how that is, is what the adaptors/conversion plugs do that I showed.

I've been doing car audio since the late 70's and when I can I use adaptors to where if I want to put things back the way it was, I can or if like on new cars, not have to worry about a dealership saying the issue is from someone cutting up the harness.

On yours, you can buy a new pigtail for the alternator with the internal regulator and then cut off the 4 terminal plug and connect the proper wires to each other.

Just make solid, long lasting connections so that later if there is an issue, you are not redoing things.

Do you have any voltage readings of when the car is off and then running ?. I do wonder if the alternator you have with just the output wire is indeed outputting due to possibly an internal modification.

Jim
 

·
Registered
Joined
·
1,491 Posts
Don't forget a fusible link in the charge wire, if there isn't one already. (As close to the alternator as possible, preferably.)
 

·
Registered
Joined
·
164 Posts
Discussion Starter #10
So I found the problem and I believe it to be strange. When I kook down into the #1 and #2 switched/gen light and sense DA prongs, I see that they are linked. They act as one plug. That is strange. When I look up pictures of internsl regulator, like the one attached, none are linked. The sense wire, which has positive power all the time is feeding back to the switched power when the ign is off and causing the gen light to stay on.
 

·
Moderator
Joined
·
6,497 Posts
This metal bridge is causing my gen light to stay on when the engine is off. See the difference?
I can see that U shaped portion going between the two tabs. I'm thinking now, like I thought before, is that someone has modified the guts inside the alternator.

I have seen some converted alternators that have these two terminals covered with a black rectangular cap and maybe through the years this cap went missing. The reason they had it covered was those terminals were not to be connected to anything.

Jim
 

·
Registered
Joined
·
164 Posts
Discussion Starter #13
I think you are right Jim. Seems like and old 3 wire internally converted to a 1 wire. This explains why it charges with nothin else hooked up. Plus the gen light on.

Im gona buy a new 3 wire one and settle this.
 
1 - 13 of 13 Posts
Top