C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Alternator

Thread Tools
 
Search this Thread
 
Old 10-16-2022, 04:18 PM
  #1  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default Alternator

Did a alternator test with a volt meter hooked to battery. Rpm about 2500. This is the reading I got. Do I need a new alternator? Car fires right up. Thanks for suggestions.
Old 10-16-2022, 04:55 PM
  #2  
interpon
Le Mans Master
Support Corvetteforum!
 
interpon's Avatar
 
Member Since: Jun 2019
Location: Indiana
Posts: 6,871
Received 2,034 Likes on 1,556 Posts
Default

I think 12.5 ok..
this is good chart i was given on this forum
if you need alternator and yours is original…KEEP it..and rebuild it.!!!

Old 10-16-2022, 05:34 PM
  #3  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by interpon
I think 12.5 ok..
this is good chart i was given on this forum
if you need alternator and yours is original…KEEP it..and rebuild it.!!!

I do t know if it is. And I don’t know how. It’s a Delco. I read that anything under 13, that it needs to be replaced.
Old 10-16-2022, 05:45 PM
  #4  
Motorvation
Racer
 
Motorvation's Avatar
 
Member Since: Jul 2018
Location: Sandusky, OH
Posts: 275
Received 107 Likes on 77 Posts
Default

Post a pic of the Part Number. The application is easy to find. http://corvettec3.ca/index.htm
I think I found the numbers for my ‘71 there. And , if you don’t want an original alt case, I’d like it.

Steve O.
Old 10-16-2022, 06:31 PM
  #5  
carriljc
Le Mans Master
 
carriljc's Avatar
 
Member Since: Jan 2001
Posts: 5,396
Received 890 Likes on 775 Posts

Default

If that thing is reading 12.4 vdc (I cannot see it for ****) at 2500 rpm, then your Alternator is not adequate. Remove it and go get it tested.

Originally Posted by 7T3stinger
Did a alternator test with a volt meter hooked to battery. Rpm about 2500. This is the reading I got. Do I need a new alternator? Car fires right up. Thanks for suggestions.
The following 2 users liked this post by carriljc:
73racevette (10-27-2022), Bikespace (10-16-2022)
Old 10-16-2022, 06:36 PM
  #6  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by carriljc
If that thing is reading 12.4 vdc (I cannot see it for ****) at 2500 rpm, then your Alternator is not adequate. Remove it and go get it tested.
Loaded it’s 12.3 loaded. 12.40 unloaded. If you touch pic you can then zoom in with your fingers.
Old 10-16-2022, 06:42 PM
  #7  
interpon
Le Mans Master
Support Corvetteforum!
 
interpon's Avatar
 
Member Since: Jun 2019
Location: Indiana
Posts: 6,871
Received 2,034 Likes on 1,556 Posts
Default

The chinesium replacements are crap..and draw more horsepower than oem..
if you are 12.4, you are on low barely out.
if driving, starting, and handling power draws ok..i would drive it…
keep an eye on it..drive around headlights on and park it and measure battery voltage..
pics of alternator? And numbers?
Old 10-16-2022, 06:57 PM
  #8  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by interpon
The chinesium replacements are crap..and draw more horsepower than oem..
if you are 12.4, you are on low barely out.
if driving, starting, and handling power draws ok..i would drive it…
keep an eye on it..drive around headlights on and park it and measure battery voltage..
pics of alternator? And numbers?
i don’t see any part numbers. It was in the car when I got it 3 years ago. Only weird thing is my temp and battery gauge act weird. Battery gauge was moving yesterday and today it sits just under 0. Temp gauge worked good yesterday and today it didn’t move. But then started moving. Here are alt pics.


Old 10-16-2022, 07:05 PM
  #9  
Blue73Shark
Burning Brakes
 
Blue73Shark's Avatar
 
Member Since: Sep 2005
Location: Lewes Delaware
Posts: 1,036
Received 193 Likes on 136 Posts

Default

That voltage is too low; it should be about 14.5V when charging. Review my recent thread:
https://www.corvetteforum.com/forums...ery-drain.html

Part number is towards the belt on the same side of altearnator casing where the 2 wire plug goes into it. see mine in attached pic.



Fran
The following users liked this post:
73racevette (10-27-2022)
Old 10-16-2022, 07:07 PM
  #10  
interpon
Le Mans Master
Support Corvetteforum!
 
interpon's Avatar
 
Member Since: Jun 2019
Location: Indiana
Posts: 6,871
Received 2,034 Likes on 1,556 Posts
Default

Take a look here for numbers..
it looks like a rebuild as it is clocked wrong..but try to see numbers anyway , unless blasted off..


Old 10-16-2022, 07:10 PM
  #11  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by Blue73Shark
That voltage is too low; it should be about 14.5V when charging. Review my recent thread:
https://www.corvetteforum.com/forums...ery-drain.html

Part number is towards the belt on the same side of altearnator casing where the 2 wire plug goes into it. see mine in attached pic.




Fran
I will go and look. Would this cause my gauges to act goofy?
Old 10-16-2022, 07:12 PM
  #12  
interpon
Le Mans Master
Support Corvetteforum!
 
interpon's Avatar
 
Member Since: Jun 2019
Location: Indiana
Posts: 6,871
Received 2,034 Likes on 1,556 Posts
Default

Maybe..
lets see what numbers say..if crap rebuild..someone can maybe recommend a non chinesium replacement..

I would make darn sure your battery cables are tight and your ground connections are tight and not corroded.

Looks like somebody’s got an extra ground(s) down there to going somewhere



Last edited by interpon; 10-16-2022 at 07:17 PM.
Old 10-16-2022, 07:14 PM
  #13  
Blue73Shark
Burning Brakes
 
Blue73Shark's Avatar
 
Member Since: Sep 2005
Location: Lewes Delaware
Posts: 1,036
Received 193 Likes on 136 Posts

Default

It could. As for a rebuilt kit. I got this one off of Ebay. A great product and it contains more parts than the NAPA kit I bought and for 1/2 the price. It has been working great.

https://www.ebay.com/itm/190606801960

Fran
The following users liked this post:
interpon (10-16-2022)
Old 10-16-2022, 07:46 PM
  #14  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by interpon
Maybe..
lets see what numbers say..if crap rebuild..someone can maybe recommend a non chinesium replacement..

I would make darn sure your battery cables are tight and your ground connections are tight and not corroded.

Looks like somebody’s got an extra ground(s) down there to going somewhere

Cant make the numbers out. All I know it’s a Delco Remy.
Old 10-16-2022, 07:52 PM
  #15  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by interpon
Take a look here for numbers..
it looks like a rebuild as it is clocked wrong..but try to see numbers anyway , unless blasted off..

What you mean clocked wrong? It’s been this way and ran fine for 3 years.
Old 10-16-2022, 08:01 PM
  #16  
interpon
Le Mans Master
Support Corvetteforum!
 
interpon's Avatar
 
Member Since: Jun 2019
Location: Indiana
Posts: 6,871
Received 2,034 Likes on 1,556 Posts
Default

If you cannot read numbers in the place they should be, it is probably a rebuild that has been blasted to oblivion, but just make sure in case original and someone rebuilt and clocked wrong.
Beng clocked wrong is about where it should be for wires, placement etc.. same alternator, 1000 applications…both halves can be split and repositioned.
What do those ground wires go to? Do you have electric fans?
this site / linkmay help
http://www.madelectrical.com/electri...elcoremy.shtml


Old 10-16-2022, 08:14 PM
  #17  
7T3stinger
Racer
Thread Starter
 
7T3stinger's Avatar
 
Member Since: Dec 2020
Location: Va.
Posts: 260
Received 41 Likes on 20 Posts
Default

Originally Posted by interpon
If you cannot read numbers in the place they should be, it is probably a rebuild that has been blasted to oblivion, but just make sure in case original and someone rebuilt and clocked wrong.
Beng clocked wrong is about where it should be for wires, placement etc.. same alternator, 1000 applications…both halves can be split and repositioned.
What do those ground wires go to? Do you have electric fans?
this site / linkmay help
http://www.madelectrical.com/electri...elcoremy.shtml

There are numbers but I will have to remove alternator and still might be readable. There is one electric fan. There used to be a msd connected but has been removed. Not sure if that ground wire has anything to do with what you asked. This is a big block car just saying.

Get notified of new replies

To Alternator

Old 10-16-2022, 08:24 PM
  #18  
bmotojoe
Safety Car
 
bmotojoe's Avatar
 
Member Since: Oct 2007
Location: Seattle Area Washington
Posts: 3,675
Received 1,298 Likes on 1,017 Posts

Default

Originally Posted by 7T3stinger
What you mean clocked wrong? It’s been this way and ran fine for 3 years.
Reading your profile you have a big block 454.
I believe your clocking is correct for your application.
Your unloaded test results are low, should be around 14 vdc.
If the loaded test was done with both the HI Beam headlights and blower motor on HI that to looks low, should be in the mid 13vdc range

Last edited by bmotojoe; 10-16-2022 at 08:30 PM.
Old 10-16-2022, 08:29 PM
  #19  
bmotojoe
Safety Car
 
bmotojoe's Avatar
 
Member Since: Oct 2007
Location: Seattle Area Washington
Posts: 3,675
Received 1,298 Likes on 1,017 Posts

Default

I don't know what was recorded in the test you had done?
Here are test results for my 80 amp alternator and good battery using a different tester.

Old 10-16-2022, 08:46 PM
  #20  
theandies
Team Owner

 
theandies's Avatar
 
Member Since: Jun 2001
Location: Virginia USA
Posts: 22,666
Received 758 Likes on 527 Posts

Default

In my experience anything under 13.5 volts while charging, loaded or unloaded is insufficient. It looks like rebuild time.


Quick Reply: Alternator



All times are GMT -4. The time now is 07:01 AM.