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Alternator help

Joined
Mar 26, 2002
Messages
812
Location
Midlothian, VA
Corvette
1981 white/blue interior automatic
Hi all,

Took the vette out today and noticed it was charging at only around 12 volts. Then the battery light came on, and the buzzer went off. Also, the choke light came on. This happened before (about 5 years ago) when my other alternator went south. I think I'll try to replace it myself this time. Looks pretty straight forward. Any tips would be GREATLY appreciated. I want to make sure I get the proper tension on the belt. Also, anyone know of a good place to get a good replacement 70 amp alternator? Mid America is out, ecklers seems to be selling cheap imports, and of course, that is all I will get from Pep Boys or Advanced. I did a seach at gmpartsdirect.com , but they say it is discontinued. Before I make a trip to the dealership, anyone have any other suggestions?

Also, could this problem not be the alternator? Thanks for all replies.

-Tatortot
 
D

Dave L.

Guest
AC-Delco part number is 321-140. Check with your local AC-Delco supplier to see if they have one. My local supplier stocks it.
 
Joined
Mar 26, 2002
Messages
812
Location
Midlothian, VA
Corvette
1981 white/blue interior automatic
Dave,

I just did a search for AC Delco part numbers and I came up with 334-2138 for the 70 amp remanufactured alternator. Is this the incorrect part? Thanks.

-Tatortot

P.S. Just called 4 local AC delco stores, none carry, nor can order me the alternator. Mid America has them on backorder, but before I place my order, they have "High Output" Alternators available.

http://www.mamotorworks.com/corvette.html?frame=4.136.5642

Do these look any good, or am I better off staying with stock? Thanks!
 

smithjw

Well-known member
Joined
Apr 3, 2003
Messages
71
Location
Modena, New York
Corvette
1981 red
I got a Powermaster model 17-294 100amp chrome. Works good, looks nice.
But before you go order yourself a new alternator, check the tension of the belt on the one you have now. It really needs to be quite tight. Just a little slippage will cause it to not charge properly.
 
Joined
Mar 26, 2002
Messages
812
Location
Midlothian, VA
Corvette
1981 white/blue interior automatic
Smithjw,

It was the first thing I checked. I had the belt replaced a year ago, and it is tight as can be. Almost no play when I try to move it. I think I remember reading 1/8" play is all that is allowed??? Nothing in the Haynes Manual that I can find. I've contacted Zip about there alternators, but still no word. I can't believe its this difficult to find one....

-Tatortot
 

Nut

Well-known member
Joined
Oct 15, 2000
Messages
890
Location
Bowie, MD
Corvette
Vette-less for now
I have talked to St.Louis 1981 guys and have been told they have found everything from factory installed 63 amps to 85 amp units in their cars. Another of the infamous "throw in whatever we have left" stories from the final months at St. Louis. Mine had a 63 amp in it and now has an 85 amp in. I would be hesitant to go much higher than 100 amps without running the risk of a fire/short due to having undersized (gauge) wiring for an alternator of that output.

....... nut :D
 

SIXFOOTER

Well-known member
Joined
Jul 15, 2007
Messages
117
Location
Boca Raton Fl
Corvette
1981 L81 Tan Coupe
You do not have to worry about wire size just because you change the alternator. You can put in a 200 amp alternator and not worry about it if that is all you changed. The reason is that if your car was drawing 47 amps when running on a 63 amp alternator and you change the alternator out for a 100 amp alternator, guess what the car will draw?
47 amps!...Reason being you didn't change the LOAD.
Now, if you put on a 100 amp alternator, Halogen lights, electric fans and a Ghetto Blaster and you send the load up to 90 amps or more, you WILL definately have to do something. For all the new stuff, I would add a new circuit to the alternator output and not run any of the new stuff thru the existing harness. Put lights and fans on relays etc..

If your concideering doing this kind of stuff, I have a really good electrical mod I came up with that will work great, reduce the electrical load on your 25 or 30 yr old harness and get you full alternator voltage at the lights, fans, stereo, battery..
If your interested let me know
 
Joined
Mar 26, 2002
Messages
812
Location
Midlothian, VA
Corvette
1981 white/blue interior automatic
Nut and Sixfooter,

I guess what you are saying is it would be fine if I ordered the higher output alternator?

-Tatortot
 

LT4man

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Joined
Jun 25, 2003
Messages
2,214
Location
Chicago
Corvette
96 Collectors Edition LT4
B

bmotojoe

Guest
Some of your larger auto recyclers (Wrecking Yards) will rebuild your alternator or starter for a fraction of the price of a rebuilt one. They tear it down wash with electrical safe solvent, bead blast outer housing, new bearings & new diode bench test. Most of the time if there not backed up as you wait. It’s been a few years ago since I last had one done for one of my other cars but it was less then $40.00 and you know that it will be correct for your application. This is exactly what you’re getting when you purchase a rebuilt and in most cases a better quality part then a cheep new import.
Brian
 

Yoda

Well-known member
Administrator
Joined
Oct 12, 2000
Messages
4,884
Location
Amarillo, TX
Corvette
1981 UL5
:w -Tator ;)

You might want to check out all the problems "gedmeyer" (our L81VetteRegistry WebMaster) went through recently with his Altenator :eek It may give you another option or at least help a bit ;)

Yea yea, I'm getting OLDER ;LOL I remember -TatorTot when he was still just a little Potato ;) :rotfl

Bud
 

Nut

Well-known member
Joined
Oct 15, 2000
Messages
890
Location
Bowie, MD
Corvette
Vette-less for now
You do not have to worry about wire size just because you change the alternator. You can put in a 200 amp alternator and not worry about it if that is all you changed. The reason is that if your car was drawing 47 amps when running on a 63 amp alternator and you change the alternator out for a 100 amp alternator, guess what the car will draw?
47 amps!...Reason being you didn't change the LOAD.
Now, if you put on a 100 amp alternator, Halogen lights, electric fans and a Ghetto Blaster and you send the load up to 90 amps or more, you WILL definately have to do something. For all the new stuff, I would add a new circuit to the alternator output and not run any of the new stuff thru the existing harness. Put lights and fans on relays etc..

If your concideering doing this kind of stuff, I have a really good electrical mod I came up with that will work great, reduce the electrical load on your 25 or 30 yr old harness and get you full alternator voltage at the lights, fans, stereo, battery..
If your interested let me know

Sixfoot..... I was assuming that someone increasing the amperage considerably was going to increase load, hence the need for the additional amps need. I concur if your loads stay stable you have no worries or issues.

........ nut :D
 

SIXFOOTER

Well-known member
Joined
Jul 15, 2007
Messages
117
Location
Boca Raton Fl
Corvette
1981 L81 Tan Coupe
Sixfoot..... I was assuming that someone increasing the amperage considerably was going to increase load, hence the need for the additional amps need. I concur if your loads stay stable you have no worries or issues.

........ nut :D
wasn't baggin on ya, lot of guys get kinda confused dealing with auto electrics, figured I'd make sure it was straight

SIX
 

Nut

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Oct 15, 2000
Messages
890
Location
Bowie, MD
Corvette
Vette-less for now
wasn't baggin on ya, lot of guys get kinda confused dealing with auto electrics, figured I'd make sure it was straight

SIX

We're good SIXFOOTER.

I have noticed that on a car 25+ years old the wiring has seen a LOT of wear, the environment, dirt, fluids, ...etc that will over time slowly degrade the jacket and especially the exposed conductors. I have replaced a couple feet of headlamp wiring and to the turn signals as those wire take a ton a crap thrown up under the car especially with mine having over 275K miles on it.

It sounds like we covered all the bases. :D An exchange of ideas and experience is always beneficial. :_rock

later.................. nut :D
 
Joined
Mar 26, 2002
Messages
812
Location
Midlothian, VA
Corvette
1981 white/blue interior automatic
Thanks for the replies everyone. Still waiting for Zip to get back to me, as they are only 15 miles or so away from me. I could order it, and pick it up, and install it all in one day. I really do think the alternator is the culprit. Like I said, this happened before.

I don't need any special tools to install the new alternator, do I? I just disconnect the battery, loosen the upper pivot bolt, then the lower, disconnect all wires and connectors, and then take it completely out, correct?? Will I have trouble getting the proper tension on the belt? That is what I'm worried about. Thanks.

-Tatortot
 

Yoda

Well-known member
Administrator
Joined
Oct 12, 2000
Messages
4,884
Location
Amarillo, TX
Corvette
1981 UL5
-Tator,

MAKE SURE the pulley for the Belt is correct "V" grooved for your original Alt. belt. Also don't exchange your old one until you get the new one installed.. you may need a puller to get the old pulley off or have the Parts House do it for you.. then make sure the belt alignment is correct ;)

Not as complicated as it sounds, just details son, details ;)

ALSO if you use the old belt, it's a whole lot easier, if you decide on a new belt.... you will need to loosen up "Stuff" to get the other 2 belts off, or figure out a new way to get the new alt. belt on ;)


Bud
 

SIXFOOTER

Well-known member
Joined
Jul 15, 2007
Messages
117
Location
Boca Raton Fl
Corvette
1981 L81 Tan Coupe
We're good SIXFOOTER.

I have noticed that on a car 25+ years old the wiring has seen a LOT of wear, the environment, dirt, fluids, ...etc that will over time slowly degrade the jacket and especially the exposed conductors. I have replaced a couple feet of headlamp wiring and to the turn signals as those wire take a ton a crap thrown up under the car especially with mine having over 275K miles on it.

It sounds like we covered all the bases. :D An exchange of ideas and experience is always beneficial. :_rock

later.................. nut :D


Wow, thats a lot of miles. I agree fully with your comments. I decided to go with relays and bigger wires for exactly those reasons. It never made any sense to me why GM decided to run all the power from the alternator back to the battery, then back up to the starter and then distribute all the power from there? WTF? Mine won't look anything like that whan I get done.
 

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