C-4 1986 Alternator

[John D.]

I found out last weekend that the alternatior on my 1986 has been replaced. The NCRS TIG shows a #1105678, 105 amp. Date has to be correct for a July 86 car.

Any suggestions where I might locate a correct dated alternator.

Vendor suggestions would be appreciated.

Thanks, John

[Joe L.]

Re: C-4 1986 Alternator

John-----

I'd try Steve Arcoleo in New York. Steve has a rather huge inventory of used C4 and C5 parts. He just might have the alternator which you seek. His phone number is 718-331-0456.

The alternator which you seek was never available as a new item in SERVICE from GM or Delco. GM and Delco SERVICED this alternator only with a rebuilt unit which may or may not have carried the original PRODUCTION part number.

[Don G.]

Re: C-4 1986 Alternator

The only way I am aware of to get a correct alternator is to find an original at a salvage yard that has the correct numbers on the mounting casting. Then buy a REMAN ACDELCO service replacement and have an ignition shop switch the mounting casting of the original to the rebuilt unit. You should then have the correct Delco Remy housing attached to the correct mounting casting. This was a high failure item and even low mileage C4's often have replacement alternators. It is my understanding that no one duplicates the GM part number/date code etching process and the REMAN units have this information removed and a silver label with the replacement part number applied over the surface.

[John D.]

Re: C-4 1986 Alternator

Joe:

Do you know what the service numbers should be for alternators with a July 1986 build? Based on having my (new (to me) 1986 judged last weekend it appears that there could be errors in the TIG. The telltale on mine was a very small stamping which I missed, but one of the judges picked up as a remanufactured unit.

I would like to try to make this alternator correct since the remanufactured unit was one of the major items found and it appears to be easily correctable. I will try to call the guy you recommend later today.

Thanks, John

[Don G.]

Re: C-4 1986 Alternator

John
The source document that confirms the 1986 alternator as 1105678 is the 1984-93 Chevrolet parts catalog dated March, 1993.

On page 2-23 there is a generator chart that states the production part number is 01105678 and that is serviced by REMAN 10497122. This part is available today under this number. As I stated in the previous post, the part number and date code that was originally etched in the mounting casting is removed in the re-manufacturing process and covered with a silver ACDELCO label with the REMAN part number. As a result you need to find an original alternator with the correct numbers on the mounting casting and install this casting on a REMAN unit.

The Judging Guide does not properly describe the location of the part number and date code for the 1986 model. It should say this information can be found on the underside of the mounting casting flange toward the engine. A mirror may be required or a piece of Scotch tape firmly pressed over the numbers will transfer the data to the tape. Again, if it is a reman unit, you will see a silver label only.

Hope this helps.

[Joe L.]

Re: C-4 1986 Alternator

John-----

The information that Don provided is absolutely correct. The GM #1105678 was the original PRODUCTION alternator used for all 1986 Corvettes. The SERVICE part number as also mentioned by Don is GM #10497122. It's still available from GM and carries a list price of $172.94 and a core charge of $10. It's also available from Delco dealers under Delco #321-286 and the price should be substantially lower.

As Don mentions, the GM rebuilds have a foil ACDelco label over the location of the original part number stamping. I've never checked, but I expect that, as Don described, the original part number may have been ground off before this label is affixed. I think that this practice is becoming more widespread in the rebuilt generator industry and is not just limited to ACDelco rebuilds.

As far as rebuilders interests go, this is probably a good practice. The original numbers on the case are meaningless and might present "confusion" which the rebuilders want to avoid since it might generate a lot of phone calls. From their perspective, the only numbers that matter are the ones that they assign to the alternator after re-manufacturing it. The original alternator "ceases to exist" and the stamped part number becomes absolutely meaningless after the alternator is re-manufactured. Remember, commercial rebuilders do not usually rebuild individual units. The cores are stripped down to component parts, the parts cleaned and reconditioned, and the alternators are assembled into units which may bear no similarity to the internal configuration of the alternator part number stamped on a case.

As a result of this unfortunate but very understandable practice, a lot of alternator part numbers are going to be lost including, perhaps, some very "valuable" ones to automotive restorers (and, not just Corvette restorers). From a restoration perspective, this is a "travesty", but it's a fact of life and a practice that's going to proceed inexorably. From the perspective of commercial rebuilders, the loss of these "numbers" is a non-issue.

While the practice of removing numbers and affixing new identification labels is going to affect ALL rebuilt alternators for all year Corvettes and other cars, it's going to be especially devastating to the "population" of C4 and C5 alternator original part numbers. There are 2 reasons for this. First, as Don pointed out, these are high-maintenence units due to their high output and vehicle elctrical demands. For well driven cars, many are replaced after 2 or 3 years by owners who could care less about "original numbers".

Second, SERVICE parts for many (but, not all) of these units have never been available from GM or aftermarket sources. Therefore, even if you wanted to rebuild your original alternator, you couldn't. So, the only way to "preserve" your original alternator is to do as Don mentioned----buy a rebuilt unit and switch cases. In the process, of course, you lose your alternator warranty, if that's important to you. In any event, how many Corvette owners are going to go through this sort of thing to preserve an original alternator? In fact, by the time an owner who cares about "original numbers" comes into the life of a Corvette, the chances are that the original alternator will be long gone, its numbers "erased" having gone through 2 or more commercial rebuilds, and installed under the hood of a Pontiac Bonneville or some such.

[David D.]

Re: C-4 1986 Alternator

John, I have an original 1986 Corvette alternator, taken off about 7-8 years ago. It has a "Y" after the part number on the case (1105678Y), then 105A and looks to be N2383 12V NEG. FWIW Dave

[David D.]

Re: Addendum

John, Forgot to mention, it also has "1Q" cast into the front housing, at the lower mounting hole, so it may be to early for your car anyway. Dave