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Old 08-26-2021, 05:15 PM
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tallrandyb tallrandyb is offline
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Question Now I understand 65 GTO's run compressors full time; anybody try POA Valve "Update"?

I have a 65 GTO with factory AC, and when I owned it originally I never learned how the AC system worked (kids ). Now I see the compressor runs any time it has power to it, and there is a "POA Valve Update" kit from Ames (P/N P120DAB) and "Deluxe POA Valve Update" kit (P/N P120DAC) that are designed to allow it to cycle (better when using R134A? how did these compressors run for hours if you were cruising and be fine before?).

Since their catalog doesn't have an actual image of P120DAB, has anyone seen/installed either one of these who can share a pic, or share results? I'd like something to look as stock as possible since the whole AC system is factory (except converted to R134A). It seems like maybe the P120DAC "Deluxe" POA looks very similar to my existing POA, I'm just not sure how the wiring harness connects and what that would look like once installed.

Thanks for any help/guidance!

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Old 08-27-2021, 11:47 AM
70GS455 70GS455 is offline
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Our A6 compressor and specifically the clutch was never designed to cycle like the modern compressors

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Old 08-27-2021, 12:47 PM
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OK, so if I have a “four seasons” brand remanufactured A6 compressor that looks like stock, running R134a, I should not worry about it. I would/should only “upgrade” the POA valve if I was running a modern-style compressor?

Thanks!

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Old 08-27-2021, 01:09 PM
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Formulabruce Formulabruce is offline
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Originally Posted by tallrandyb View Post
OK, so if I have a “four seasons” brand remanufactured A6 compressor that looks like stock, running R134a, I should not worry about it. I would/should only “upgrade” the POA valve if I was running a modern-style compressor?

Thanks!
The biggest problem ends up being the compressor Electromagnetic CLUTCH with using a A6 compressor in a cycling system with R12, or 134a.
Back in the day the clutches, wiring to it, and front seal were common repairs
at the GM dealership I worked at.
While we didn't sell Buicks, we sure did install their "splash shields" on Pontiacs.

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Old 08-27-2021, 02:05 PM
70GS455 70GS455 is offline
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Yes, the newer radial conpressors like the R4 were designed to cycle in the CCOT systems.

If you're running R134, calibrate your POA valve for that pressure (youtube) and maybe adjust your TXV if the superheat is not in a good zone. A parallel condensor will help but is not necessary

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Old 08-27-2021, 02:55 PM
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Originally Posted by 70GS455 View Post
Yes, the newer radial conpressors like the R4 were designed to cycle in the CCOT systems.

If you're running R134, calibrate your POA valve for that pressure (youtube) and maybe adjust your TXV if the superheat is not in a good zone. A parallel condensor will help but is not necessary

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From what I understand these earlier compressors don't have a superheat/switch. Literally all there is is one power wire to the clutch, with its second wire going to ground, right?

The AC runs cold with the system configured when I bought it, and we just evacuated/refilled the system to insure we had the correct amount of R134a versus the factory-spec R12 fill.

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Old 08-27-2021, 03:16 PM
70GS455 70GS455 is offline
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Originally Posted by tallrandyb View Post
From what I understand these earlier compressors don't have a superheat/switch. Literally all there is is one power wire to the clutch, with its second wire going to ground, right?



The AC runs cold with the system configured when I bought it, and we just evacuated/refilled the system to insure we had the correct amount of R134a versus the factory-spec R12 fill.
Correct on the wiring.

The superheat im talking about is the temperature rise across the evaporator, you adjust the TVX for flow to put it in the optimal range for conditions, and to prevent slugging

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Old 08-27-2021, 03:16 PM
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Didn't all GM cars go CCOT starting in 1977 to replace the expensive VIR unit from '75-'76? And the A6 was still used for several more years after '76, so if those are so susceptible to failure when operated in a cycling application, why didn't we hear about slews of these things failing at an early age? Would have been another GM PR fiasco as the 200C and Olds diesels were...

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