Are the older 72 AC POA valves extinct?

[Lugnutt]

I've been looking and looking to see if I can find a replacement for my original POA valve for my AC. It seems like nobody makes replacements. Please, does anybody know of anyone that makes new or rebuilds these? Or can these POA valves be repaired and re-used? If possible, I would like to keep my old system functioning like it did in 72.

I don't know why I'm reluctant to upgrade to a cycling system, but I am and I sure could use you guy's help if it's possible.

Thanks, and I'm sorry if I'm being such a stic-in-da-mud on this.

pic attached

[john]

They have them here when available. I would consider the upgrade kit if I want to keep the factory air.

[bodydropped68]

Originally Posted by Lugnutt

I've been looking and looking to see if I can find a replacement for my original POA valve for my AC. It seems like nobody makes replacements. Please, does anybody know of anyone that makes new or rebuilds these? Or can these POA valves be repaired and re-used? If possible, I would like to keep my old system functioning like it did in 72.

I don't know why I'm reluctant to upgrade to a cycling system, but I am and I sure could use you guy's help if it's possible.

Thanks, and I'm sorry if I'm being such a stic-in-da-mud on this.

pic attached

old air products makes a kit to get rid of your poa valve, it works well and not that expensive, converts to a pressure cycleing switch.

[BACKYARD88]

Holy crap! Get the price on that thing. You could almost buy an entire new A/M system for that.
Edit: Here's an NOS one for a car, looks the same to me. I bet if you called them they could tell you if it is. 6th POA from the top.
http://thepartguy.com/ac-valvesALL.htm

[Lugnutt]

Whoa, yea! Maybe I'll just settle for a thermos of lemonade; although I'm tempted. I do have 3 cans of R12 left over from before the big tear in the ozone a few years ago so I think I'll use that till I run out. Also, I think I'll consider the kit Bodydrop recomended and live with the cycling.

Thanks for the help with the link guys

[Texasbigblock]

I know brotherstrucks makes one, but not sure on the price

[roughedup72]

Just recently did the conversion on my truck to the r134a and updated poa. works pretty good but I have noticed that it doesn't seem to be cooling as good as I would like for it to. What does the cycling mean? is it supposed to cut the compressor on and off or what. Mine seems to be running all the time. I pulled a vac. down on it and everything is good. I also had a shop charge the system so its full of freon. Any body got any suggestions as what could be causing it to not cool as good as it should be? and I'm sorry for hyjacking your thread. Just thought that now would be a good time to ask this rather long question.

[Texasdeere]

Cycling isn't necessarily a good thing. It is better if the compressor stays running on a properly working system. Cycling is usually caused by a low charge, freeze up, or it is just not that hot outside.

When does your truck not cool that well? Some times the problem may be the heater not turning off completely or a duct work problem.

[Lugnutt]

Hey Rough,

No problem with your coments, they're great.

My mechanic told me that R12 has a cooling performance advantage over the R134c freon around town when there's not alot of air flow, but on the freeway there's not much difference. I've heard that adding an electric AC fan in front of the radiator might help; might want to check that out.

I remember comments in 73 when they switched-over to the cycling system on these AC units that they were going to wear out the compressors engaging and disengaging constantly at freeway speeds. I don't know, just talk I remember from back then... cursed my thinking about it, unfortunately, though I think now I'm heading that direction myself.

Something else that I also need to re-check on my truck. There is a chamber in the heater box under the dash that has a large flapper gate moved by one of the heater/ac slider controls. If I remember, it deverted the airflow from the bottom vents to the front AC vents. I've had mine break before (cheap plastic axis attachment) and it left it stuck in whatever position it was when it broke. You might want to take that apart a little and peek inside to make sure it's working ok.

Hope you get your system working soon

[Andy4639]

I have changed over to the later cycling system and it performs well. Yes the motor idleing the temp will rise, but when moving it will cool as good as anything else.
Things to consider when swaping over to 134-A system:
get rid of the dryer and put the acumalator on it. Have it vacumed and charged by a A/C company.
Buy a condensor for 134-A they are bigger tubes than a 30 year old condensor for R-12. 134-A has to expand more to be effective in it cooling.
Here is a thread I did on my conersion.
http://67-72chevytrucks.com/vboard/s...d.php?t=253275

Condensor:

Evaperator & acumliator:

Compressor and new hoses:

[JimKshortstep4x4]

Lugnutt,

We run the POA valves in the four trucks that we have with AC and they work well. We test the POA valves before installation, adjusting if needed.

I pick up POA valves in my local yard for use when I need one. The fitting locations need to be matched so to make sure of the interchange.

Jim

[mrein3]

Originally Posted by JimKshortstep4x4

Lugnutt,

I pick up POA valves in my local yard for use when I need one. The fitting locations need to be matched so to make sure of the interchange.

Jim

If your POA is no longer functioning, just go to the yard and grab one or two. ANY GM product of this vintage will have this type of system. As JimK points out, just get one with the fittings pointing in the proper direction.

And don't cycle your A6 compressor, it wasn't designed to do this.

R134a, as others have pointed out, just doesn't work as good as R12. In my 1972 Chevelle, with a properly tuned POA system and R12, when I get out of my car to get the mail, my glasses fog up. I've NEVER had an R134a system do that. And if you're stuck in stop and go traffic with R134a, forget it. You need lots of air flow across the condenser to make it work right.

I don't think the R134a condensers have larger tubes, I think they have LOTS of little tubes. Thus increasing the area the air can flow across. That is probably why folks who converted to 134a and didn't update the condenser don't have as good of performance.

Remember, compared to a car, the area in a truck cab is small. 134a, while you're moving down the road will get the job done.

One more little tid bit. I had the HVAC guy over the other day to resurrect my house AC. He is a car guy, and a Chevelle guy so we got to talking about cars and of course AC. I mentioned I might know where a sealed 30 pound tank of R12 is, whats it worth. He said that there are two new drop in replacements for R12 out there so the price just started to fall. To make a really long post short, if you're thinking of converting to R134a, you might want to sniff around for these two R12 replacements.

[roughedup72]

So I should get rid of the dryer and use an accumulater and make sure that the condenser is for a 134a system. I had to order a new condenser and I told them it was for a 134a system but I think the one I got is still for r12. I also use a a6 compressor. Its not cycling or if it is its not noticeable.

[Andy4639]

Mrein3,
Sorry you are correct the tubes are smaller but more of them, it was late and I didn't proof read it well 01:02 AM . My 134-a system does fine except for the sitting in traffic but once I get a electric fan mounted it should be fine. The other day it was 102 degree's here with high humidity and I was running 46-48 degree's in the truck going down the road.

[mrein3]

As long as we're on the subject, there is some good stuff here:
http://www.epa.gov/ozone/title6/609/.../retrguid.html
Note that the SAE no longer believes you need to flush old R12 oil before filling with R134a and oil.

If you're going to R134a in a stock system, don't forget to read this link:
http://www.autoacforum.com/messagevi...AR_MSGDBTABLE=

[seanu]

Lots of good info in this post..thanks

[Andy4639]

You may want to check these guys out.
They say they will rebuild anypart out there for GM.
http://www.classicair.com/GM-Factory.asp

[roughedup72]

I double checked my condenser and it does have more tubes than the stock condenser. So it appears to be for 134. Whats the difference between the accumulator and the drier.

[BCOWANWHEELS]

Just Put Propane In For A R12 Subsitute And Will Cool Better Than R12. I Use It And Have For Years. But Your System Needs To Be In Good Condition..... No Leaks............
Bob

[Andy4639]

BCOWANWHEELS,
Are you not worried about the down side of using propane! One spark in the right place or should I say in the wrong place and BOOM! Nomore BCOWANWHEELS!
That just sounds to scary for me.