OK...need some old school auto A/C help

I have a buddy (new no doubt) since I do A/C and Refrig. And his question was can I get his Classic car A/C going. He sent me these pictures. And in

45 yr, I have not seen an apparatus like this on a GM A/C unit. Here is the site I put the pics up on:
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JB
Reply to
daytona°
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That's a 1958 Chevy 348 Tri-Power and you need this book...

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welcome. Jerry

Reply to
IRONDOG

The part I assume you are referring to is a hot gas bypass valve. It is there to prevent the evap from freezing up. It also has some adjustment there so the evap temp can be raised slightly when max cooling capacity is not needed. Larry

Reply to
lp13-30

To keep everybody from getting to each others breakfast cereal.....it is a

1959 Chevrolet convertible with A/C and a 348 with trips. Great pick-up on the pictures. Now the hot gas bypass.....with a choke cable??? I can see a possible leak in the mechanism. I know that he needs dash controls....the temp lever is gone completely, but he said they obtainable. I advise to wait and see if the system can be tight or made tight. I did work a 1960 of the same motor, but had a completely different compressor and setup. It was more aftermarket for 1960

Reply to
daytona°

This application has always baffled me. Why go to the bother of installing a hot gas by-pass and all the crap that goes with it, when a simple low ambient would seem capable of doing the job.

I say this after just working on a McQuay unit with repeated nuisance resets.

Reply to
U-Hate-Me

Years ago, GM did not want their compressors cycled off and on for temperature control. Funny though, their dealer installed under dash units, called "CoolPack", did exactly that and AFAIK used the same compressors. They used hot gas bypass until 1962 when they switched to suction throttling valve (basically an EPR-- their terminology, not mine). In 1965 they switched to POA valve which did about the same function. Somewhere around 1974 they went to a VIR (valve in reciever) system. I think they switched all their system to orifice tube and cycling clutch in 1977, though they first came out on 1973 p/u's and Vegas. FWIW, the hot gas bypass line tied ino the outlet of the evap right at the txv bulb, rather than just dumping hot gas back into the compressor. I still have my book from auto a/c class in 1972, though some of it is not in the best of condition. If the OP wants any info, I will be glad to make some copies and mail them. I have no way to scan/Email them tho. Larry

Reply to
lp13-30

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