A/C Compressor Pulley Identification

[Bryan M.]

I have this pulley in my parts stash. I think it's for a A-6 a/c compressor. Can someone tell me the application? The diameter is 3 5/8". I don't see a part id on the pulley.

[Wayne M.]

Re: A/C Compressor Pulley Identification

Looks like and the diameter matches some of the hi-horse alternator pulleys on the C2's and C3's. Except that the depression for the nut seems deeper than I'd expect; and the finish is dark.

Here's an A6 compressor pulley; clutch removed, note the friction surface on the pulley (face scored, on this one). Most A6 pulleys are ~4.6" to 6_3/8" dia.

[Bryan M.]

Re: A/C Compressor Pulley Identification

The size does remind you of an alternator pulley. This thing is heavy too. The bathroom scale shows 2 lbs.

[Bryan M.]

Re: A/C Compressor Pulley Identification

Could it be for a generator?

[Dick W.]

Re: A/C Compressor Pulley Identification

Believe it is an alternator pulley

[Bryan M.]

Re: A/C Compressor Pulley Identification

Believe it is an alternator pulley

Dick,
Do you have any idea what application it might be for?

[Bryan M.]

Re: A/C Compressor Pulley Identification

Looks like and the diameter matches some of the hi-horse alternator pulleys on the C2's and C3's. Except that the depression for the nut seems deeper than I'd expect; and the finish is dark.

Here's an A6 compressor pulley; clutch removed, note the friction surface on the pulley (face scored, on this one). Most A6 pulleys are ~4.6" to 6_3/8" dia.

Wayne,
I did find this pic of an alternator pulley in the archives. It looks very similar.

[Wayne M.]

Re: A/C Compressor Pulley Identification

Could it be for a generator?

I see in my parts catalog that similar 3_5/8 diameter pulleys with 1/2 inch groove used in '57 thru '62 cars have integral fans. I believe generators made use of the keyway.

Here's a similar pulley (to yours) off a 42 amp 1100696 on a July 1965 alternator, which I believe to be original. Probably part # 3871242. This weighs 2.8 lbs.

If you imagine that the first shallow conical depression was not machined, then the center depression would look like yours, IMO.

[Wayne M.]

Re: A/C Compressor Pulley Identification

Wayne,
I did find this pic of an alternator pulley in the archives. It looks very similar.

small world -- that's my alternator that I just posted the pulley pics (front/back) from. Is the back of yours machined flat (like my example) ? I've seen some backs cast finish in the center with the outer edge machined, and I believe these may be # 3829193, same hi-horse but for '63-4 (and maybe up to Oct '64 -- early '65s, going by the change revision in the '65 AIM).

[Bryan M.]

Re: A/C Compressor Pulley Identification

small world -- that's my alternator that I just posted the pulley pics (front/back) from. Is the back of yours machined flat (like my example) ? I've seen some backs cast finish in the center with the outer edge machined, and I believe these may be # 3829193, same hi-horse but for '63-4 (and maybe up to Oct '64 -- early '65s, going by the change revision in the '65 AIM).

Yes, I copied the pic from one of your old post and the backside is machined flat. So this application could be for a hi-po 327 without a/c?

Did some of these pulleys come without a stamped ID?

And, I wish I could change the title of this thread to alternator pulley id.

[Bryan M.]

Re: A/C Compressor Pulley Identification

I think I might have found the answer.

Some time ago, there was an interesting discussion about the 3829387 alternator pulley used for 65 and later big blocks. The discussion focused on the part number and code that may or may not have been stamped on the face of the pulley. At first, the discussion seemed to indicate that all of these pulleys were stamped. Eventually, it was decided that the number was stamped starting some time in early 1965.
A few claimed that no number would have been on this part until some time into the 66 model year. Others strongly disagreed.

A VERY interesting article in the new Restorer magazine by Herb Larsen may show that, indeed, NO early/mid production 65's and most likely no early 66 cars had a stamped pulley.
Included in the article is the GM print for the 3829387 pulley. In the revision list, it shows that the stamp was ADDED to the print on 19 May 1965. (doesn't mean they started stamping pulleys on 19 May 65)

That means all pulleys made prior to that date were unstamped. It also means that it may be SEVERAL months before stamped pulleys actually made their way out of their source and into bins on the assembly line.
It's unlikely that any 65 car would have left the plant with a stamped pulley. It's also possible that early 66 cars may have had unstamped pulleys also.

I always wondered about this because my Nov 65 built 66 has what I always thought was the original unstamped pulley. I've seen many other examples of unrestored mid/late 1965 CY cars/alternators over the decades too that do not have the stamp.