The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 11-16-2002, 08:48 PM   #1
BigRusty7072
Registered User
 
Join Date: Sep 2002
Location: Chesaning, Mi
Posts: 32
Alternator Swap Problem

I recently swapped out the old alternator on my 70 and put in a new one, which is internally regulated. Per replies to an earlier thread, I used the oldsmobile troubleshooting page for the wiring conversion. The alternator charges great and works great, but theres one problem. When I hook up the battery, I can hear the old regulator click, as if somethings drawing somehow. Is this normal, or have I messed something up?? I dont want that thing drawing on my battery every time I let it set.
__________________
Scott Moore
70 Chevy 3/4 ton Custom Camper

72 Chevy 3/4 ton 4X4
BigRusty7072 is offline   Reply With Quote
Old 11-16-2002, 08:59 PM   #2
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
You need to bypass it like this;
Attached Images
 
Longhorn Man is offline   Reply With Quote
Old 11-16-2002, 09:06 PM   #3
BigRusty7072
Registered User
 
Join Date: Sep 2002
Location: Chesaning, Mi
Posts: 32
I bypassed it like that, only the hidden way. I sotered the wires on the back of the regulator together(in the same order you have), and clipped the resistor.
__________________
Scott Moore
70 Chevy 3/4 ton Custom Camper

72 Chevy 3/4 ton 4X4
BigRusty7072 is offline   Reply With Quote
Old 11-16-2002, 11:04 PM   #4
Piston
Account Suspended
 
Piston's Avatar
 
Join Date: Oct 2002
Location: Olathe, KS
Posts: 2,300
Ok yall can have a good laugh now.... Tech? YES, Artist? NO lol.

The wiring used for the old style system was only designed for 50A or so. Newer alternators can be anywhere from 70 - 130A so if your upgrading the charging system, might as well upgrade the wiring for the alternator.

I've drawn a small diagram thats easy to follow (I think?).
Items needed:
3ft 10ga wire with eyelet connectors
6ft 14ga wire with butt connectors
1 pigtail for GM alternator.

Run the output straight to the junction block near the battery.
Run the red wire from the GM pigtail directly to the output of the alternator.
Run the white wire from the GM pigtail to the brown wire of your old regulator (disconnect the old regulator harness).

I can tell a huge difference in output after making the change. I used to run the new alternator using the existing wiring... Now its able to charge straight to the battery (which most all cars have gone to this configuration now)

Dont laugh (much)... here comes the diagram

Piston is offline   Reply With Quote
Old 11-16-2002, 11:25 PM   #5
mikep
Used to have a truck
 
mikep's Avatar
 
Join Date: May 2002
Location: port orchard WA
Posts: 1,552
Make sure you run a 100 ohm resistor in your circuit you have marked as red or you will overload the exciting diode and fry your alternator eventually. My boss went through 3 in 2 years before he finally listened to me.
__________________
No truck :-(
mikep is offline   Reply With Quote
Old 11-16-2002, 11:34 PM   #6
Piston
Account Suspended
 
Piston's Avatar
 
Join Date: Oct 2002
Location: Olathe, KS
Posts: 2,300
The only difference in running the wire like that vs. running it from the old regulator is voltage. It may see a .5v spike every now and then.

Now if you hook 12v to the excitor wire, you'll burn a diode trio faster than anything lol. The white wire generally has 4-5v present with key on. The red wire is only to power the field circuit.
Piston is offline   Reply With Quote
Old 11-17-2002, 10:35 AM   #7
racedvl
Account Suspended
 
racedvl's Avatar
 
Join Date: Jan 2000
Location: Woodstock, IL
Posts: 7,020
That picture that Andy used is a picture of my truck. I did that over 2 years ago, and I have had zero problems with my charging system.
racedvl is offline   Reply With Quote
Old 11-17-2002, 12:24 PM   #8
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
While mine has only been converted for a year, I to have had no problems whatsoever out of mine.
On the Longhorn harness, I bypassed the regulater all together, and upgraded the wireing in the harness with some thicker (I dunno what guage) wires.
Longhorn Man is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 03:22 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com