Factory A/C: POA Valve or Cycling switch?

[F.A.A.benny]

Curious as to how many guys out there went with a poa delete kit, did they like it and why did they choose it over the poa valve. Im guessing cost can be a deciding factor as those delete kits are around $100 and it a little more to get the original poa valve rebuilt.

[Davidf]

Not knowing any better at the time, I rebuilt the a/c system in my '71 (did not operate when I purchased the truck) utilizing a POA delete kit. I elected to stay with R12. Well, it took me about 2 miles down the road to figure out I made a mistake. The darn thing causes the compressor to cycle excessively....constantly on/off is more like it. When the compressors cycles off, there is a total and noticeable lack of cooling in the cabin. Also, the constant loading and unloading of the engine is simply annoying.

So, I built a test rig and calibrated my original POA to 29.5 psi and ripped that POA delete tube out and but the POA in where it belonged. Much better, but not perfect. I occasionally get less than cold air out of the vents.

[Andy4639]

I changed mine out years ago to make it look cleaner under the hood. I like it a lot better than the old POA valve.

[engineer_gregh]

I went with the delete kit and regret it. I should have stayed with the POA valve. Davidf is right about the cycling and it being annoying.

[1972RedNeck]

Originally Posted by Andy4639

I changed mine out years ago to make it look cleaner under the hood. I like it a lot better than the old POA valve.

This is the right way to do it.

I would recommend not deleting the POA valve if you run the factory A6 compressor as the clutches are known to eventually fail in a clutch cycling system.

[72freak]

What did you do with the metal line that came out of the box and screwed into the POA valve?

[lsversaw]

What does POA stand for?
Posted via Mobile Device

[72freak]

Originally Posted by lsversaw

What does POA stand for?
Posted via Mobile Device

In most circles it means a really stupid idea that luckily was changed quickly.....in others it means Pilot Operated Absolute Valve

[F.A.A.benny]

Originally Posted by 72freak

What did you do with the metal line that came out of the box and screwed into the POA valve?

He replaced the original evaporator with one probably from a square body truck

[F.A.A.benny]

Originally Posted by 72freak

In most circles it means a really stupid idea that luckily was changed quickly.....in others it means Pilot Operated Absolute Valve

The poa valve was actually not changed for quite a while. It came around 1966 and used into the mid 70s. Gm completely changed over in 1974 and Ford used them for a few yrs.

[leddzepp]

I've never had any poa issues personally. An old auto AC tech told me they are pretty reliable, and 9 times out of 10 the expansion valve fails before it does. Not sure how true that is, but so far this has been my experience.

[davischevy]

I run the POA valve on all my old junk, and they work fine.

If you can get R12 do it, but I recalibrated my POA and it works fine with R134.

[tdangle]

I still have the POA valve in mine. Went to recalibrate it and it was already at 27 so I just left it alone. Running R134 for now

[Bob B.]

Originally Posted by lsversaw

What does POA stand for?
Posted via Mobile Device

Pilot Operated Absolute pressure valve. It's job is to maintain a certain pressure in the evaporator by regulating the suction of the compressor. It works in conjunction with the expansion valve, which controls liquid refrigerant flow into the evaporator. A cycling system does the same thing by turning the compressor on and off by use of a low pressure switch on the line coming out of the evaporator.

Conversion to a cycling system will work, but I don't think it's an ideal solution. This is particularly true if you are still using the original A6 style compressor, they were not designed to cycle (though GM did use them in some of the early cycling systems).

I stayed with the POA on my own truck (had it recalibrated for R134A) and a buddy did same on a '72 El Camino. Both systems work great.

[DT1]

Originally Posted by Bob B.

Pilot Operated Absolute pressure valve. It's job is to maintain a certain pressure in the evaporator by regulating the suction of the compressor. It works in conjunction with the expansion valve, which controls liquid refrigerant flow into the evaporator. A cycling system does the same thing by turning the compressor on and off by use of a low pressure switch on the line coming out of the evaporator.

Conversion to a cycling system will work, but I don't think it's an ideal solution. This is particularly true if you are still using the original A6 style compressor, they were not designed to cycle (though GM did use them in some of the early cycling systems).

I stayed with the POA on my own truck (had it recalibrated for R134A) and a buddy did same on a '72 El Camino. Both systems work great.

Is there a write up somewhere for the R134A re-calibration procedure?

[davischevy]

Just do a search. Lots of info out there on the web.

[F.A.A.benny]

Originally Posted by DT1

Is there a write up somewhere for the R134A re-calibration procedure?

Many online say to turn the set screw 1/4 Of a turn counterclockwise. It I find it not to be very pricise. I use guages and compressed air. What I believe it most important though it is to know whether or not the valve is functioning correctly or even at all. Can't do that with just turning the screw. Unless you knew the valve was functioning fine before recalibrating it, turning the screw won't work and you wont know until after you have charged the system

[Bob B.]

Originally Posted by DT1

Is there a write up somewhere for the R134A re-calibration procedure?

I used these guys:

https://originalair.com/restoration-gm-poa-valves

Sent my old valve in as a core, got one of their remanufactured and recalibrated for R-134A valves in exchange.

Yes, you can probably get by with a guesstimate valve adjustment, but you really should figure out exactly what pressure it is opening at, as others have pointed out in this thread. That's the best advise I can give you, good luck!

[F.A.A.benny]

Originally Posted by Bob B.

I used these guys:

https://originalair.com/restoration-gm-poa-valves

Sent my old valve in as a core, got one of their remanufactured and recalibrated for R-134A valves in exchange.

Yes, you can probably get by with a guesstimate valve adjustment, but you really should figure out exactly what pressure it is opening at, as others have pointed out in this thread. That's the best advise I can give you, good luck!

I used to work for them. That's where I learned how to rebuild poa valves.

[davischevy]

So F.A.A.benny do you rebuild and rebuild the valves now?

[strider621]

I used the POA delete kit from Ecklers and upgraded to R134A. Kept the old POA valve but new one is working fine.

[F.A.A.benny]

Originally Posted by davischevy

So F.A.A.benny do you rebuild and rebuild the valves now?

Yep I still rebuild poa valves

[jjzepplin]

WOW! That sure is a nice valve there sir. Price?

[F.A.A.benny]

Thanks. It's $175 outright. I include free shipping to the lower48. To rebuild your poa valve is $125 with same shipping included

[jjzepplin]

Good deal. I am going to be using R134. Should I remove the R12 MUFFLER? I am assuming this is the large canister style deal in the aluminum line.