Engine Size: 350
Refrigerant Type: r134
Country of Origin: United States
After reading a ton of posts here I've decided to go with the factory A/C setup. I'm going to go with the biggest parallel flow condenser I can fit and adjust the POA valve down to 26 psi. I do have a couple questions I hope someone can answer.
1. I'm running a serpentine belt setup that uses a R4 compressor. So, I'd like to stay with it even though it probably isn't the best comp. out there. Someone does make brackets to adapt a Sanden comp. to the serpentine setup, so I could go that route if it is a better option. Out of those two which would work better in my app.?
2. Both of those are meant to be ran in a cycling system. Without using a POA eliminator, what options do I have to cycle the comp. or will that be a problem? Would a trinary switch work for this?
3. Either way I plan to use the trinary sw. to run a condenser fan. Where should it go in the system? Between the POA and comp.?
4. There is a guy on ebay selling a kit (expansion valve, POA valve) that coverts the system to a internal equalization system. Is there any benefit with this over the stock external equalization setup?
Thank you for your time!
With a POA system, you do not cycle the compressor. The POA valve throttles the suction side to prevent evaporator freez-up, and the TXV throttles the evaporator inlet. This is a continous control system.
The sanden should do ok with suction throttling. Be sure there is enough oi lin the system, and that the oil bleed is woring corectly in the POA valve. The TXV / POA system is a great way to make cold air - much better than the "bang-bang" control of the CCOT systems.
I can't say how well the R4 will do with POA operation - they are not the best compressor GM ever built. Perhaps one of the others here has used an R4 sucessfully in a POA system. Guys?
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
How can I make sure the oil bleed is working right? I have tested the POA by blowing air through the TXV with a gauge on the low side and it's right at 30psi. I haven't adjusted it yet because I'm still not 100% on using r134. Is there a way to test the TXV? It is cheap to replace, but I don't like the EXTRA long coils on the new ones. If I stay with r12 will a PF condenser still help?
Anyone else know if the R4 comp. will work?
R-134a and the R-4 is the worst combination out there-- many replacements on '94-95 trucks -due to internal yoke wear- noise is the complaint- the yokes wear and the compressor knocks so loud you can hear it a block away. I never convert R-4s- keep them with R-12 and mineral oil--- or in your case, I would seriously consider the Sanden alternative-- unless you plan on replacing the R-4 ever other year or so.....
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
A6 was the best compressor GM has ever built, been all downhill since then, what's wrong with using that? And R-12 is still available, okay, so I am not keeping up with the times, but those were good times. Trying to add up the hundreds of thousands of miles I had R-12 with A6's without problems, has to be at least over 800,000 miles.
Now when the EPA banned R-12, demanded recovery, introduced R-134a with those stupid ports, aluminum condensers, poor GM seals, rotten evaporator cores, that's when I started having problems.
Edited: Tue March 10, 2009 at 12:00 PM by NickD
I would take a Valeo/Seltec TM16 or TM21 before I would use an A6 with R134a in this case. Now the new A6 replacement hitting the streets would be a great option also.
10H20 - A6 Replacement
The OP is running a "later" model serpentine belt setup, so an A6 is not an option for him.
Considering that the POA was only used with a compressor with a sump (A6), wouldn't a POA with an R4 and R134a be potentially even worse than '94-95 trucks due to oil starvation?
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