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Looks as though he is talking about the S6 compressor Classic and many others sell, aluminum rotary with the same dimensions and mounting arrangement as the A6. It likely is everything they say, and on a car used every day with AC I might consider it. But given the cost, and that an A6 belongs under the hood of a classic Corvette, and that the old A6 works fine, I'd be inclined to have mine fixed or replaced.
OP, I think you are talking about the Pro6Ten compressor. I have had one on my car for 3 years. It fits the oem brackets and hoses. I was told it pulls 3-4 hp as compared to about 12 for the A6. It still pulls down the rpm but not as bad as the A6. I painted mine black and I have no issues with it. I bought mine from Old Air but Amazon has it now. I replaced my A6 because the front seal was leaking.
Get Dom Tallarita in California to rebuild it. He will do a first class job using the the best parts. Sorry dont have contact info but I believe he is a forum member.
Last edited by Donald #31176; 05-01-2020 at 10:13 AM.
If you want a reliable compressor, get the new ALMA A6. Identical to the original, except better internals and seal.......and metric threads. Put the correct decal on it and no one can tell the difference.
But if you show the car or want to keep the original, Dom is the guy you want. But even Dom has trouble sourcing seals for the old units that will hold up over time. You simply cannot buy a great seal for these old compressors any more.....if you ever could.
ALMA compressors use a double lip seal and a chromed main shaft to get "modern" sealing. So far I think they are doing it right.
Cost for Dom or new A6 are likely about the same. If I had to drive the car frequently/regularly I would buy new...........but I would also have Dom rebuild my old one and keep it around. Dom is a friend, and the best we have in the USA on rebuilding these old A6 units. But he is also constrained by availability of quality parts for a 60 year old compressor design.
Awhile back we had SupremeDeluxe evaluate the current ACDELCO seal for the A6, and he stated it did not meet minimum industry standards. I still have his reports. They are all likely made overseas now and only cost about $15/seal. So you can figure what a $15 part made off-shore is capable of. The front seal is the weak link in the A6 design. I guess if we as a hobby were willing to say John Crane or Chesterton $500 to $1000 for a seal for these compressors, we could get one that is much better. But even then, I am not sure the minimum quantity required to produce them at this cost would be there.
Larry
PS (edit): The Pro6Ten appears to be a good unit as well, and should be considered. Not certain it is any better than a new ALMA compressor, and the ALMA looks like the original. But both should be fine if you want new.
Last edited by Powershift; 05-01-2020 at 12:11 PM.
I'm currently running a pro6ten compressor in my '67. Uses alll the factory brackets and connections. I installed it as an alternative to my old A6 compressor because it weighs about 50% less than an A6 which weights 34 lbs, it's quieter and more efficient. In the picture, you'll notice that i installed a shield over the front pulley to deter any oil being slung onto my hood. This has proven to be unnecessary as the front seal hasn't leaked at all.
I did have Dom rebuild the original A6 compressor and it came out beautifully. I haven't installed it yet as the pro6ten is functioning just fine. I'm happy with both decisions I made.
Last edited by leif.anderson93; 05-02-2020 at 01:44 PM.
National Seals had a machine that could custom create any seal up to 12” diameter. You tell them shaft speed, ID, OD etc and they could custom build one seal or more for you. They started doing this back in the 90’s. You could choose the seal material to match your needs. One seal could be $200 but if it was unobtainable it was worth it. The called it Redi Seal. I did not confirm they still offer it.
If you want a reliable compressor, get the new ALMA A6. Identical to the original, except better internals and seal.......and metric threads. Put the correct decal on it and no one can tell the difference.
But if you show the car or want to keep the original, Dom is the guy you want. But even Dom has trouble sourcing seals for the old units that will hold up over time. You simply cannot buy a great seal for these old compressors any more.....if you ever could.
ALMA compressors use a double lip seal and a chromed main shaft to get "modern" sealing. So far I think they are doing it right.
Cost for Dom or new A6 are likely about the same. If I had to drive the car frequently/regularly I would buy new...........but I would also have Dom rebuild my old one and keep it around. Dom is a friend, and the best we have in the USA on rebuilding these old A6 units. But he is also constrained by availability of quality parts for a 60 year old compressor design.
Awhile back we had SupremeDeluxe evaluate the current ACDELCO seal for the A6, and he stated it did not meet minimum industry standards. I still have his reports. They are all likely made overseas now and only cost about $15/seal. So you can figure what a $15 part made off-shore is capable of. The front seal is the weak link in the A6 design. I guess if we as a hobby were willing to say John Crane or Chesterton $500 to $1000 for a seal for these compressors, we could get one that is much better. But even then, I am not sure the minimum quantity required to produce them at this cost would be there.
Larry
PS (edit): The Pro6Ten appears to be a good unit as well, and should be considered. Not certain it is any better than a new ALMA compressor, and the ALMA looks like the original. But both should be fine if you want new.
Larry is absolutely correct with everything he said. As you'll see Larry is very knowledgeable and a great resource to a lot of forum questions. Dominic is the best at rebuilding the original A6 units as he did mine. The Alma A6 compressors are new and not rebuilds and are the best option if your not going back with a CORRECT date coded A6 and you still want it to look correct to the car. There are a few vendors you can get the Alma A6 from and i acquired this information from one of the head Alma Sales Rep. Here is the Vendors he provided to me:
Zip Corvette Part # AH-224 - Phone # 800-962-9632 (399.99 Plus shipping) Ranshu - 800-524-4559 (Quoted $456.75 + $20 shipping) Florida Region Omega - 972-812-7098 (Never contacted them and you'll have to ask to be transferred to Sales Dept?
05-01-2020, 12:15 AM
1963-1976 Corvette Compressor A6 Replacement - Worth the change?
The front seal is the weak link in the A6 design. I guess if we as a hobby were willing to say John Crane or Chesterton $500 to $1000 for a seal for these compressors, we could get one that is much better. But even then, I am not sure the minimum quantity required to produce them at this cost would be there.
