Engine Size: 425
Refrigerant Type: was R12
I am towards the end of a frame off restoration of a 1966 Oldsmobile Toronado. The AC is on my to do list right now.
Status as of today is that the condenser and evaporator are cleaned, flushed and leak tested.
My idea is to keep the old Frigidair A6 compressor , refurbish it using new seals and clutch bearing adjust the POA to a lower pressure, change the oil for PAG oil, get new barrier hoses and keep the POA system with a new charge of R134a.
I read a lot about upgrading old AC systems and what seems to a rule of thumb are the following things:
If I want to keep the POA it has to be adjusted for R134a;
A POA eliminator kit and the then cycling system seems to be not good for the old A6 clutch in the long run;
A good Fridgidair A6, although big heavy and power consuming, outperforms all the new stuff in regards to longevity,
So now, as I found this forum, what would you guys suggest?
I am tending towards a seal set and clutch bearing for the A6, have new barrier hoses built and get a new dryer. POA and the expansion valve have question marks..??
Questions, questionsÃ¢ÂÂ¦.. I guess you know some answers?
Best regards from germany
Edited: Tue February 18, 2014 at 4:54 AM by harascho
some more info / pics on my system:
the POA Valve
looking inside from both sides shows a clean, rust free component
current state of restauration:
Why don't you want to keep it R=12 ? That seems like the logical thing to do to me.
R12 is not available in Germany
Make sure your drier is 134a compatible. Newly manufactured ones generally are, and are labeled as such. A NOS drier should not be used because it's probably saturated with water already anyway, and putting R-134a into it will cause the internal plastic to come apart.
You might get away with the old type condenser in Germany, but in hot climates a condenser upgrade would be strongly advised.
Edited: Tue February 18, 2014 at 12:47 PM by mk378
My idea is to keep the original parts for the start. I am aware that my condenser might be a problem. An electric fan in front of it might also be of help.
I sent my infos to Tim and hope he comes with some suggestions... I need new hoses, dryer, gasket set for the A6 and a lot more. I also try to keep the POA. We will see. I hope they offer a POA check/adjustment service?
Edited: Wed February 19, 2014 at 12:51 AM by harascho
Was really a great system, got involved with this in a year old 1965 Buick Electra, only a 12 month warranty back then. Did come with a fairly new fan clutch, got rid of that in a big hurry as lower Buick's didn't have this new wonderful invention and drove the fan directly. What a huge difference that made.
Back then, could go to a wrecking yard and get all the parts I needed for a buck for the conversion and it didn't make a bit of difference in fuel economy. GM also came out with a charging station to measure liquid refrigerant by volume. But installed a sight glass in the high pressure line, idea was to get pure liquid feeding the POA valve. But this had to be done on a warm day, doors open, engine at 1,500 rpm, AC on, blower at maximum, and would leave just a small traces of bubbles in the sight glass. Worked beautifully.
Compressor would run all the time, POA was set at 28.5 psi and should stay there over the ambient temperature range, unlike this CCOT systems they came out later with a constantly cycling compressor. But did install a rocker switch in the lower left dash panel in series with the clutch coil so I could switch it off. Recall driving it through South Dakota on a 125*F day, plenty of cooling. But no sense in running it on a 60*F or lower temperature day.
But the only refrigerant available at this time was R-12, recall reading post on this system with conversions, can't recall anyone being successful, but never had to do this. Still can use gauges on it, but really have to watch the high side pressures. No high side pressure cutoff on these things, safety valve on the compressor would blow it out. If you can't hold reasonable pressures, far less than 400 psi, may have to switch to a parallel flow condenser. On a hot day.
And old board member, Mitch was going to tackle this problem with an R-134a conversion, but suddenly died.
Still feel we got a raw deal on R-12, from all scientific facts, was a biodegradable refrigerant. If it did break down in the ozone layer, chlorine does not exist in nature and would return to its natural state and more O2 molecules would go up there. From all characteristics, R-134a does not break down and is now blamed for global warming so planning on getting rid of this refrigerant as well. MVAC use of R-12 was less than 2% of the total production, but not enough for the likes of Al Gore that started all this. You can't fight city hall.
Major cause of ozone depletion has always been the earth kicking up methane, but they can't do anything about this, but sure can pick on a can of R-12. PAG is the chief lubricant used in R-134a, and a real PITA for working on AC systems, now have to be purged and flushed or else you will get sludge in the system. Just making life a lot more miserable. And our EPA only picks on techs, never addressed the OE's for leakage problems they created with crap. And couldn't come up with anything worse than R-134a ports that leak constantly.
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