A6 pulley size conclusion

[Domenic T.]

A while back I posted about the 72 A6 pulley size and now know that the C3's started using 2 size pulleys, starting in 1969. The BB 69 used the
5 1/4" and the SB used the 5 3/4".
The C2 used the 5 3/4" on all but the 327/365 HP, it used a 6 3/8"

63 used a completely different way. It was a metal tag with #'s that did not make sense. The tag was spot welded on.
64-65 with 327/365 HP- model #5910490
64-65 all other #6550133
66 #6550113 NOTE, the last 3 #'s. 113 and 133 on the 64 ,65, 66.
67 all #5910645

68 #5910645 same as 67 but model# offset to the right -5 3/4" pulleyI cannot
69 SB #5910645 " " " "
69-71 BB #5910740
70-71 BB #5910741
72-73 SB #1131002 5 3/4" pulley
72-73 BB #5910797 5 1/4" pulley
74-76 #5910741

I cannot verify the 69 SB using the 5 3/4" and the BB using the 5 1/4" but it follows the only 2 size pulleys used nor did
I confirm the 74-76 all size

Dom

[Leif A.]

Re: A6 pulley size conclusion

Great info Dom. Check your email regarding the compressor we've been talking about. Thanx.

[Mike B.]

Re: A6 pulley size conclusion

Good Stuff Dom. Always good to hear from the master. Take care, Mike

[Domenic T.]

Re: A6 pulley size conclusion

Mike,
Think yours was the one that sparked the investigation, Pm me if you have a copy or E-mail (dtallarita1@aol.com) I can't find your invoice and I would like to keep it on file. My paperwork suffers.
Solved!

Dom

[Mike B.]

Re: A6 pulley size conclusion

Hi Dom,

Sending you an e-mail.

Mike

[Domenic T.]

Re: A6 pulley size conclusion

Mike,
I am sure it was the post on your comp that helped getting things straight about pulley size. I learned a bunch from that and was able to do some research on what little we know about the A6.
MODEL ! that was the answer.
This means when one buys a C3 corvette compressor, the need to know BB or SB, or change the pulley and foil sticker.

Dom

[Mike B.]

Re: A6 pulley size conclusion

Dom,

I really enjoyed that thread. It was a big success! Tons of posts. I learned a lot too and I made some good NCRS buddies along the way. Always great to hear from you!

Mike

[Joe L.]

Re: A6 pulley size conclusion

A while back I posted about the 72 A6 pulley size and now know that the C3's started using 2 size pulleys, starting in 1969. The BB 69 used the
5 1/4" and the SB used the 5 3/4".
The C2 used the 5 3/4" on all but the 327/365 HP, it used a 6 3/8"

63 used a completely different way. It was a metal tag with #'s that did not make sense. The tag was spot welded on.
64-65 with 327/365 HP- model #5910490
64-65 all other #6550133
66 #6550113 NOTE, the last 3 #'s. 113 and 133 on the 64 ,65, 66.
67 all #5910645

68 #5910645 same as 67 but model# offset to the right -5 3/4" pulleyI cannot
69 SB #5910645 " " " "
69-71 BB #5910740
70-71 BB #5910741
72-73 SB #1131002 5 3/4" pulley
72-73 BB #5910797 5 1/4" pulley
74-76 #5910741

I cannot verify the 69 SB using the 5 3/4" and the BB using the 5 1/4" but it follows the only 2 size pulleys used nor did
I confirm the 74-76 all size

Dom

Dom-------


None of these compressors were ever available from GM in SERVICE, at least not under these part numbers.

[Domenic T.]

Re: A6 pulley size conclusion

Joe,
With all respect those are not part numbers! they are model numbers. NO ONE knows part numbers for a A6 compressor or anything else other than if it doesn't leak and works it's good.
When did the low compression pistons come out? Was only in the 65 manual. What size pulleys? Best is what I posted.
Joe the A6 IS the LEAST known in judging or otherwise. I did close to 150 and still don't have all the answers.
HELP!

Dom

[Joe L.]

Re: A6 pulley size conclusion

Joe,
With all respect those are not part numbers! they are model numbers. NO ONE knows part numbers for a A6 compressor or anything else other than if it doesn't leak and works it's good.
When did the low compression pistons come out? Was only in the 65 manual. What size pulleys? Best is what I posted.
Joe the A6 IS the LEAST known in judging or otherwise. I did close to 150 and still don't have all the answers.
HELP!

Dom

Dom---

Yes, they are shown on the compressor label as "model no.". However, the numbers are too close to the series of numbers used by the Frigidaire Division of GM for A/C component part numbers not to be a part number. In addition, these numbers will be found in the various AIM's for the compressor assembly. The AIM's do not call out model numbers, per se; they call out part numbers. So, these numbers represent PRODUCTION-only part numbers. Why SERVICE part numbers were different, I do not know, for sure. However, I expect it was because GM SERVICE compressors did not include a clutch/pulley whereas PRODUCTION assemblies did include the clutch/pulley.

[Domenic T.]

Re: A6 pulley size conclusion

Joe,
I will have to say it was hard to understand what you posted.
I will say that the A6 should have different PART NUMBERS, (not to include clutch, or pulley)!
#1 1963 had spot welded data plates with ONLY 3 mounting 3/8 NC thread.
#2 1964 went to 4 mounting 3/8 Nc threads
#3 In the 1965 manual the A6 changed their pistons to low compression by a dish on the piston head .100 deep by 1.00 wide
#4 After 1975 they, again the A6 changed their piston design from metal rings to a machined ring surface to use teflon rings.
#5 The A6 (mid 66) went to a welded outer case to a swaged case.
#6 The outer case removed the pan baffle
#7 the inner case baffle was changed back in 1963
I would think that there SHOULD be a part # change for all 7 excluding ANY clutch change which happened in mid 1966 or a pulley
size or belt (double or single) on about most cars built, including the RR.
Also the A6 was used on aircraft.
WHERE are the different part numbers?
Model numbers also include a red warning and a green warning on the foil with the exception of the 1964-65 using a seperate warning label under the foil.
I think there should be a part # for each change, don't you?
I scratched my head looking at compressors (that were supposed to be Corvette) to make sense out of all the miss matched parts such as,
starters, alternators, generators, carbs, and so on.
The A6 IS the least known under the hood.
I have more but I have sworn not to disclose due to judged cars in the past.

Dom
THIS IS NOT KNOWN IN ANY BOOK WE KNOW THAT EXISTS TODAY.

[Joe L.]

Re: A6 pulley size conclusion

Joe,
I will have to say it was hard to understand what you posted.
I will say that the A6 should have different PART NUMBERS, (not to include clutch, or pulley)!
#1 1963 had spot welded data plates with ONLY 3 mounting 3/8 NC thread.
#2 1964 went to 4 mounting 3/8 Nc threads
#3 In the 1965 manual the A6 changed their pistons to low compression by a dish on the piston head .100 deep by 1.00 wide
#4 After 1975 they, again the A6 changed their piston design from metal rings to a machined ring surface to use teflon rings.
#5 The A6 (mid 66) went to a welded outer case to a swaged case.
#6 The outer case removed the pan baffle
#7 the inner case baffle was changed back in 1963
I would think that there SHOULD be a part # change for all 7 excluding ANY clutch change which happened in mid 1966 or a pulley
size or belt (double or single) on about most cars built, including the RR.
Also the A6 was used on aircraft.
WHERE are the different part numbers?
Model numbers also include a red warning and a green warning on the foil with the exception of the 1964-65 using a seperate warning label under the foil.
I think there should be a part # for each change, don't you?
I scratched my head looking at compressors (that were supposed to be Corvette) to make sense out of all the miss matched parts such as,
starters, alternators, generators, carbs, and so on.
The A6 IS the least known under the hood.
I have more but I have sworn not to disclose due to judged cars in the past.

Dom
THIS IS NOT KNOWN IN ANY BOOK WE KNOW THAT EXISTS TODAY.

Dom-------


The compressor model number and compressor part number are the same. Most, if not all, of the compressor part numbers that you mentioned will be found in the various 1963-75 AIM's. However, the compressors used in PRODUCTION (i.e. installed at St. Louis) included the compressor + clutch/pulley. This type of assembly was never available in SERVICE (i.e. parts you could obtain at a GM parts counter). In SERVICE, the compressor and clutch/pulley were only available separately. So, the part numbers were different than any parts used on the assembly line. That's not to say that the components were actually different than those used on the assembly line. In other words, the combination of the SERVICE compressor + the SERVICE clutch/pulley = the part number for the assembly used in PRODUCTION. For example, the GM #5910494 compressor + the GM #5914724 clutch/pulley= the GM #5910490 assembly used in PRODUCTION.

The SERVICE part numbers for the compressor were as follows. Keep in mind that these compressors do not include the clutch/pulley:

1963-68 (except 2nd design 1966)-----GM #5910495

1969-76 (plus, 2nd design 1966)-------GM #5910432

Some 1972-76 used GM #6598452. It's not clear from the information I have which used the 5910432 and which used the 6598452.

The following clutch/pulleys were used

1963-68 (except 1963-65 SHP)---GM #5914745-----5-5/8" OD (may be slightly different depending how measured)

1963-65 SHP-------GM #5914724------this is likely the 6-3/8" clutch/pulley. It was discontinued without supersession inFebruary, 1971.

1969-70 and 1970-74 454--------GM #6550750----5-1/8" (may be slightly different depending on how measured)

1971-72 350-------------GM #6550482---I have no OD information on this pulley

1973 350-----------------GM #5914745----5-5/8" (may be slightly different depending upon how measured)

1975-76------------------GM #6551249----I have no OD information on this pulley

[Domenic T.]

Re: A6 pulley size conclusion

I just did a lengthy post and lost it when the forum logged me out!
It was the difference in the 1963 compressor, it did not have a foil, instead it had 2 spot welded plates, one had useful data, 6550133 and the other had a confusing code such as 75NC3785. Other 63's had similar confusing codes.
The 63 back plate number was the same as all up to 1972 even though it only had 3 mounting holes on the back plate instead of 4 that were on for the remainder.
Some back plates had the date code on the back plate under the manifold centered between both ports and some date codes were to the right on the back plate under the right port. This makes me wonder if there were more than one making parts? There were up to 3 shifts completing compressors and GM was not the manufacturer using the A6!
To be continued on next

Dom

[Domenic T.]

Re: A6 pulley size conclusion

Some compressor owners claim the comp was never removed, and some were the original. Not known to many but being that the validity of compressors starts with the back plate date (which is shared by all made that day), there is a casting date on the front plate under the clutch that should be within a week or so from the back plate date. The difference between those 2 dates is a give away, some are years apart. Another is the piston dish (lack of) and another, the GM black teflon looking sealer missing and the inner parts that were assembled without sealer by a re-builder.
Next to the back plate date being important is the case Swaged or welded, Then the pulley size, clutch, and last the foil.
The clutch and case design changed mid 1966.
The 1963 to mod 1966 clutch had 6 apx 7/32 holes on the face opposed to the 3 spoke like clutch that was there to the end. In mid 1966 the case changed from a weld to a swage on the case about 3/8" just behind the pulley.
Inside the case 1963 had a metal baffle using a rubber gasket that was on the inner case that the crank and works were in. After 63 the baffle design changed to a one piece metal. Then another baffle was used in the outer case just over the pan. Eventually that baffle was eliminated in the 70;s.
Last is the foil with the model # and completion date typed in the CODE box. That date and shift is also shared with all the compressors made that day. There is NO serial # on the A6.

Dom

[Domenic T.]

Re: A6 pulley size conclusion

Joe, Thank's a million for the info. I was hoping you would get involved! I spend hours trying to explain or answer questions. I think my thanks and appreciation was lost when the forum logged my post out.
By chance I have a 63 comp with a 6550108 on the metal spot welded tag, I am sure it is not corvette but is there a way to see what GM car it came from. clutch, pulley, and hub were all correct for a vette, but again the parts were mixed and matched.
Thanks for all the good info.

Dom