I'm in the process of restoring the A/C and heater systems in my '71. The evap housing is removed and disassembled for cleaning and paint. The heater core is next. My question is - would I benefit from using a POA valve "update" kit when I reassemble the A/C? I do plan to convert to R134A.

Thanks

 

For the little bit of cost and seeing that you are replacing a lot of the old parts anyways I would and I did when I restored mine. I however used DuraCool vs R134. Duracool actually restores the full coldness of the system that R134 does not. It is enviornmental safe and less costly then R134.

 

Thanks - to use duracool do you still need to use a R-134A conversion kit?

 

No. I bought the kit from Corvette Central and only used the O rings, still have the oil and the connectors. If the system was not taken apart all it needs is a good evacuate of the system and then install the Duracool. I had the system evacuated prior to replacing many of the old parts such as the receiver dryer, condenser, hoses etc. but because the system was apart they need to do it again, 30 mins of shop time then they added some compressor oil, give the system a good vacum then filled it with Duracool. Works great and is as cold as I can remember from the orginal system. Duracool uses the orginal compressor oil. Only cost me $86. labor, $17 for the refrigerent oil and $50 for the Duracool.

 

First of all, I am not an AC expert, but I have been learning about the AC on my 1972 with a POA valve.
From what I read, the POA update kit causes the air to cycle on and off like newer cars (the original POA system did not cycle, it is on all the time). This could cause the idle problems, and could cause surging when the AC cycles during driving especially with lower horse power.
Also, I did not want to hijack zdozbou's thread, so to answer your POA adjustment question, you could check out the writeup forum member Zwede provided when he converted his 1971 to from R12 to R134 (I do not have the web address I copied the info but I am sure he could point you in the right direction.) He mentioned not all POA's were adjustable, he bought an adjustable one from NAPA just before they were discontinued. Here is a quote from his website:
"POA Valve adjustment. The POA Valve regulates the pressure inside the Evaporator. It is set for R12's optimum pressure of 29.5 PSI. To get maximum efficiency from R134A it has to be adjusted for lower pressure. Looking into the inlet of the valve (through the fitting where the hose to the evaporator goes), an adjustment screw with a locknut can be seen. Loosen the locknut and turn the adjustment 1/4 turn counter-clockwise. This adjustment lowered my vent temperatures from 52F to 43F on a 90F day!"
I hope this helps.

 

Thanks for all of the replies. I don't think I would like the compressor cycling on and off; my wife's Chrysler does that and you KNOW it while driving. I'll keep the POA and look at Duracool.