AC POA valve conversion
Thread Starter
Instructor
Joined: Jul 2002
Posts: 132
Likes: 0
From: Virginia Beach Va.
AC POA valve conversion
Has anyone tried converting their POA valve to Clutch Cycling Orifice Tube operation. I've seen a conversion kit for about $99.00. If so did it improve the cooling ability of the system?
Thanks, Bob
Thanks, Bob
Race Director
Joined: Sep 1999
Posts: 11,358
Likes: 379
From: Plano TX
Re: AC POA valve conversion (GR8T WYT)
If your POA system works, keep it. It's my understanding the CCOT conversion is not an upgrade, but rather is for when your POA valve is busted and you can't find a new one. They're very hard to get a hold of these days.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Re: AC POA valve conversion (vettfixr)
I've not done a Corvette with one, but have done a 68 Camaro (R12) and a 68 Firebird (R134). Both customers were still happy with the conversion last I spoke with them.
Thread Starter
Instructor
Joined: Jul 2002
Posts: 132
Likes: 0
From: Virginia Beach Va.
Re: AC POA valve conversion (GR8T WYT)
I've discovered thru research that the POA valve has an adjustment screw located inside the valve that controls the pressure at the valve. If you convert to 134A you need to turn this screw a 1/4 turn counterclockwise. R-12 likes 29.5 PSI and R134A likes 26.5 PSI. The adjustment should show 10 degrees +or- lower temps at the vents provided the rest of the system is in good working order. I bet not to many people or AC techs know about this procedure and therefore blame the134A for the poor cooling. I'm going to try this before I go switching valves but not till next spring when I plan to do some serious engine detailing and will open up the AC system to remove it. If anyone attemps this in the near future let us know the results. Bob
Melting Slicks
Joined: May 2002
Posts: 2,716
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
Re: AC POA valve conversion (GR8T WYT)
If possible stay with the POA. The fixed orifice is not as efficient as a variable orifice. The POA or an expansion valve will be more efficient at varying engine rpm’s, as it will adjust for the change. I have read that an aftermarket company has designed and marketed a variable orifice to replace the GM fixed orifice the reviews that I read looked good.
Just my 2 cents.
:)
Just my 2 cents.
:)
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
Re: AC POA valve conversion (GR8T WYT)
I stuck with the (adjusted) POA variable orafice to prevent cycling while driving. Also, I'm not sure if the A-6 would hold up with a cycling system, even though it's probably THE toughest compressor ever.
Hans
Hans
