DPosey

I am collecting info for a jump to install R134 in my recently acquired 1968 442. I noticed on OPGI, the parts store, they offer a POA valve upgrade for this conversion. In reading numerous forums, this switch has never been discussed. Do I need to switch out the POA valve, or will the old one assimilate okay to R 134 ?

Fun71

The original one can be adjusted for R134A. There is a screw (or bolt?) inside the large opening that is turned to reduce the pressure and thereby reduce the temperature in the evaporator. There should be several posts about this that you can find by searching the forums.

edit:

I found it for you:

https://classicoldsmobile.com/forums...2-cutlass.html

DPosey

Thank you very much for the help and the link.

oddball

The "upgrades" are cycling suction valves that replace the POA. It's not a "better" setup, just different. It's simpler and better than a broken POA, but a correctly adjusted and functioning stock system, especially with a parallel flow condenser, can work well.
The A6 was not designed to cycle on and off, so the cycling switches can be hard on them.

DPosey

So you guys sound very knowledgable in this arena, what is the best long term solution for me? I currently have a stock system that is blowing hot air, but is still under pressure, and an A6 compressor.
Am I trying to fit a round peg thru a cooler square hole, or should I replace the entire system, and start fresh, even if the old system appears to be working..

TIA,

Doug

Fun71

My recommendation is to ensure all the parts of your current system are functioning correctly, there are no leaks, then charge it with R12.

DPosey

Whats your view on R-12a ?
Better off buying regular R-12 off eBay ?

joe_padavano

This is true, however GM did use the A6 in cycling applications from the factory in the late 1970s. The problem is the rotating inertia of the A6 wreaks havoc with the clutch and belts when you cycle them a lot.

I spent a lot of time looking in to this for my 67 Delta. I ended up going with the Sanden conversion sold by Classic Auto Air and the POA valve eliminator kit. I was going to keep the POA valve, but the price and long turnaround time to rebuild and recalibrate made the choice for me. The Sanden compressor can be used either way. I did get a new expansion valve calibrated for 134. Classic Auto Air has developed a bracket kit for mounting the Sanden on an Olds motor.

oddball

Err...... Is that a thing? I'm pretty confident there's no adjustment on the expansion valves or meaningful way to alter their functionality.


OP: "best" is subjective. Avoid R-12a "freeze 12" or any other mixed junk. They put some other gas, usually propane, into the mix that kinda-sorta works as a refrigerant. It's better than having air in there, but it doesn't work well. Gets you out of the parts store parking lot though.

If you can find R-12 or someone that has it, then that works well with all the original stuff.

If you retrofit to R-134a you have the usual retrofit problems (flushing, adjusting, potential condenser upgrade, etc).

Just depends on how much you want to spend and what you want to do with the car. Some folks stick with R-12. I went for the parallel flow condenser, adjusted POA and Pro6Ten.

joe_padavano

OK, I'll rephrase that. I bought a new expansion valve, as the old one was pretty well crudded up.

banny

I rebuild the poa valves all the time. If you need to have yours done, its typically a few days. I used to work at Classic Auto Air. Rebuilding poa valves was the first thing they trained me on

68442Convertible

I'm no expert - so please jump in with comments and opinions - but it seems to me that the big drawback of sticking with R-12 and the A6 compressor is that it will probably leak if your car sits for long periods without running the A/C due to the seal design in the A6. Converting to R-134a makes the periodic recharge less painful.

I store my car for months - no other option. Probably a different story if you can run the A/C regularly.

troyd

DISCLAIMER: Your mileage may vary.....so I'm just laying out my experience which that and ten bucks might get you a cup of coffee at Starbucks.

If you know that all your original bits and pieces are working (and this is a big IF).....why not just stick with r12? If you have a stock system, it was optimized to run r12. It's still out there and while not cheap......if your system is in good nick, a can a year, while not chump change isn't cost prohibitive.....so, in my mind, I wouldn't do it from a cost saving perspective.

To me, if you are thinking conversion......a new condenser is probably a must, new hoses probably not a bad idea either and pretty soon you are talking way more money than just had a shot of r12 added every year. So, that's what I did.....new evaporator, hoses, TX valve, Pro6ten (sp) compressor, condenser, recalibrated POA valve (which is easy to do) and viola....I got bitchin' cold AC. At the appropriate price.

The cycling switch.....I've heard good and bad both ways but the gist seems to be if you are using the original A6, stick with the POA valve either way. If you go with the newer compressors it's six of one, half dozen to the other.......

What was my point? I don't really remember but the fiscal sanity reason in any of this is mythical. I'm just saying if it works as is....why mess with it?

Cheers,

Troy

DPosey

I agree totally, thx for all of the responses.