Engine Size: 327
Refrigerant Type: 134a
Country of Origin: United States
I have just converted my factory a/c system in my 67 camaro to 134. Outside temp. around 90 and vent temp 52 at it's lowest. Thought that was fine until I started researching. Just about everything I found so far is my original POA valve needs a lower psi when converting to 134 and that will lower the temp 5-8 degrees. That wasn't done. Every post I read about this process stated there is an adjustment screw inside the inlet of the POA and it should be turned counter clockwise 1/4 to 1/2 turn to lower the pressure. That seems to work from all the posts I have read. My question is, would a 1967 POA even have that screw to adjust? I saw a post that had a picture of a POA with a "nut" instead of a screw. A response to that picture and post was that only the "factory replacement POA's had the screw and not the original one's. Is that true and will I need to buy a re-calibrated POA from Classic Auto Air? Anyone here have an old POA like mine with the adjustment screw? Thanks!
Most POA's have a screw inside that is adjustable. You will find a nut that takes a 7/32 socket and the "screw head" is a flattened head that needs to be grabbed with a pair of long nosed pliers. The nut when tightened again will usually grab the screw and it will move so it is trial and error to get the screw in the correct place. It usually takes a few tries. 1/4 to 1/2 turn counterclockwise works unless you have th adaptor tool to measure the PSI which is the best most accurate way. You are looking to set it at 26 psi.
So, I guess I won't know if my POA is adjustable or not unless I discharge the system and open up the valve. I was hoping I could get someone's attention that had one from 1967 or so that could tell me if that year is adjustable. Thanks.
I have never seen a GM POA that was not adjustable.
They used the same valve for decades - everything after the STV was the same.
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
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