76 Alternator

[Brian Maier]

I know this message will fire a lot of people up, so here goes. My battery does not appear to be holding a charge. I have not yet confirmed it, but assuming I need a new alternator, would getting a rebuilt alternator at Autozone interfere with the status of the car in terms of it being "Numbers Matching?" In other words, if I don't retain this original alternator, will the car still be considered numbers matching? I got new stainless steel sleeved calipers and new pads and rotors about a year and a half ago and sold the originals as cores. The engine and transmission are numbers matching. Thanks for your help.

--Brian




BW's Stingray

[Jim T.]

Re: 76 Alternator

Brian if your alternator is the actual one that your car left the factory with it is part of the package of your original equipment and has identifiable information as to its output and dated information stamped in the housing.
The amount of money Auto-Zone will give you for your core when buying a rebuilt alternater is not very much anyway.
I made the mistake in the mid-seventies before I became a member of the NCRS and learned of the importance of keeping the original starter and alternator for a car.
Today I would either just save the part and pay the core charge or have the part rebuilt.
You said your battery does not hold a charge. Why do you think your alternator is needing replacement when your battery is not holding a charge?

[Brian Maier]

Re: 76 Alternator

Jim,

I had the battery tested and it had a low charge. They put a charge on it for 10 minutes at Autozone and said it was just a low charge. I have not investigated the problem fully yet. I put the car back in the battery and fired it up and it worked. I have not driven or cranked it again since the other day. I need to drive the car over there to get the alternator/battery/starter tested. I am just afraid it won't start again and I'll have to jump it or pop the clutch again. My main concern was if I should need to replace that part (or any other for that matter) should I save the part or have it replaced? I am not sure how many of the parts are original, other than the engine and tranny. Thanks for your input!

--Brian

[Paul B.]

Re: 76 Alternator

Brian, I'd believe your battery in it probably has a "dead cell" in it and no matter how much you charge it, it will still go dead and batteries WILL NOT hold a charge with a dead cell. Also, the original alternators do have a part # on them corresponding to your car not having A/C, having A/C etc. They are also date coded too. It'd be cheaper to have your "original" alternator rebuilt than to buy another. Check your local area yellow pages for "electric motor" or "alternator rebuilding" services in your area. I had my original 1980 alt rebuilt(not restored for originality purposes) for $20 including new bearings and brushes.

[Duke W.]

Re: 76 Alternator

If your voltmeter indicates 13.5 to 14.5 volts when the engine is running the alternator is okay. A shorted battery cell is the most likely cause of your discharge.

If the alternator is bad, it is easy to rebuild. You can separate the frames and replace any electrical part without taking off the pulley. All the static electrical checks are in any GM overhaul manual from the era.

SOP is to replace the regulator and brushes. You also run the static checks on the rotor and stator, and they usually check out. You can inspect the rear bearing visually and if the rotor turns smoothly on the front bearing there is no need to change it.

In the event you ever need to replace an component like and alternator, starter motor, water pump, etc. to get the running quickly, NEVER, EVER turn in an original Corvette component as a core. Pay the core charge and rebuild the original at your convenience or send it out to a shop that specialized in rebuilding original components and will insure you your original back.

Duke

Duke

[Brian Maier]

Re: 76 Alternator

I appreciate everyone's help. I will look in to the dead cell idea. It was weird, because when I drove it the other day, none of the electrical components worked: windows wouldn't roll up, no turn signals, no radio, no tach for much of the ride. When I tried to roll the windows up or down I could hear the revs drop and the tach dropped a couple hundred RPM's or so as well. The car used to sit a lot when my Grandpa owned it. It probably didn't get driven more than a few times a year...the battery was always dead and he'd have to put it on charge. When he gave it to me a year and a half ago I began driving it once or twice a week. I now drive it about once a week or so. And have been mostly for the past year. I do appreciate the advice as to saving the original parts. If you look on my website, you see one of the previous owners has put American Racing Aluminum wheels on it. I don't know what kind or where the original wheels are. THanks again!

--BW




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[Jim T.]

Re: 76 Alternator

Brian from what you have written here about the past history of your car it seems to me that your alternator would routinely be tasked to charge a somewhat discharged battery due to the car not being driven often.
When a car sits more than it is driven I would recommend having a battery charger at home that prior to driving the car the battery is fully slow charged before driving the car. You could also use your charger to maintain a fully charged battery when the car is not being driven.
The alternator is really being overworked when it always has to charge a low battery every time the car is driven.
Something else you could do is disconnect the battery during periods the car is not being used. Other than removing one of the terminals from the battery behind the seat you could just lay on the garage floor and disconnect the ground cable from the frame. I use this method because its the easiest for me.

[Brian Maier]

Re: 76 Alternator

Jim:

Actually, Grandpa installed a cutoff switch on the ground side of the battery. Its a simple brass lever switch that cutts off the current. At one time, something was killing the battery. I think that it was the burglar alarm. When I took the car to a Corvette bodyshop for some work on a quarter panel, the owner of the shop pulled out the relay for the alarm and it seems to be fine now. However, I still disconnect the battery overnight. Grandpa did have a charger, however he didn't keep it fully charged until I requested we drive it. That switch is a really cool thing though. The battery is four and a half years old. It is older than I thought. I am also going to get the seatbelt rebuilt from Ssnake Oyl. The retractor doesn't work. Right now it is set for just my size by a small clamp. I think I am about ready to sell the car. I'm not looking forward to it. But I just don't think I have the mechanical knowledge I hoped I had and I have put almost $4k into it since he gave me the car in August '00. I'm open to any suggestions you can offer about corvettes. THanks for all your help!

--Brian




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