R12 to 134 conversion
What is involved with doing this conversion correctly.
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Re: R12 to 134 conversion
Keith, have you studied this change. I have 134 in my 63 and I'm going back to R12 as it cools much better. Essentially you evacuate the sytem, change the schrader valves then recharge the system. In a C2 you use 3.5 lbs of R12 and 3.0 lbs of 134.
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Re: R12 to 134 conversion
Yes i have studied the change over. What i am understanding is that you must change out the complete system for it to work properly. Although i do have the same concerns that it will not cool.How did you find someone to convert it back to R-12? I am under the impression no one has this machines anymore.Comment
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Re: R12 to 134 conversion
Keith, I had 134 in my '65 and went back to R-12. It made about 6-8 degrees difference (at the outlet). Another consideration is the oil you have in the system. Ester oil is good for either (134 or R-12), PAG is 134 only. I am not an AC expert but that is what I have been told. As far as who does the conversion, I did it myself. I did have to flush the system (going 134 to R-12) because it had the wrong oil. You can buy a solution specifically for flushing. Good luck, Don H.Comment
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Re: R12 to 134 conversion
I have two R12 cars and have not converted them. Back in the nineties when I attended the SEMA show for several years I talked to all the AC service system manufacturers, and they all highly recommended sticking with R12 as long as it was available, and they further added that there were huge stockpiles.
I haven't had a R12 car serviced since 2009, but my understanding is that there are still huge stockpiles of R12, and the price is coming down because of low demand, and in some cases it may be cheaper than R134a. Most R12 cars have been converted or are no longer being serviced because they are already one major repair away from the boneyard. IIRC the last R12 cars were 1993, so they are now all over 20 years old.
The problem is finding a shop that still services R12 systems since so few people still have them in operation, but search around your area and stick with R12 if at all possible.
As stated in previous replies, the conversion issues are flushing the old mineral oil completely out and the lack of R134a cooling performance compared to R12. It can be improved by substituting a higher capacity condenser, but that can add a lot of cost of the conversion.
DukeComment
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Re: R12 to 134 conversion
I have only R-12 in my '60s cars. It is pretty easy to find, my college roommate went into WalMart when it was being phased out and bought the maximum number of cans he could each day, so he has a huge stash, as do many others I know. They also bought the DuPont "A/C conditioner charge" bottles, which help lubricate and condition the system prior to charging.Big Tanks In the High Mountains of New MexicoComment
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Re: R12 to 134 conversion
Thanks for all the help guys!!
I will stick with the R-12, It must be my lucky day, the first shop i called still services R-12. $50.00 a pound is the price quoted for R-12
KeithComment
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Re: R12 to 134 conversion
At the risk of opening a can of worms, check out a product called DuraCool as a replacement for R12. I've used it for years and it is an excellent product.Comment
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Re: R12 to 134 conversion
Kieth,
I converted to 134 in my 74 Laguna S3 and it keeps me cool in Palm Springs. I kept the R12 valves and made a simple adapter to service the system that was removable. Everything still looked stock. If you already have R12 in your system a good shop can recover it, work on your system, and put it back in, then add what is needed.
DomComment
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Re: R12 to 134 conversion
Just picked up a 30lb tank of R12. The price was way lower than it was a few years back.
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Re: R12 to 134 conversion
Duke,
Some shops advertised a "hot shot", propane. I did I once years ago. It's flammable alright but so was the gasoline and oil so it was rationalized that way. Weren't there legalities attached to the use of R12?
DomComment
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Re: R12 to 134 conversion
Although my A/C system is non functional at present, I bought all the fixins' back in the 90's for when I do restore it. N.O.S.- evaporator,condensor,V.I.R., rebuilt correct compressor. And at BJ's a 30# can of R-12 set me back a whopping $237. Wish I bought 10 of them! Now if I could just find the '73 454 only manifold...I'd be done. Or someone with the correct crimping dies to make a new one. My original has a non factory splice in it! Re-pros have an obvious different crimp on the hoses!
I'd try and stay with the R-12!
1973 LS-4 454 coupe owned 24 years
1996 LT-4 Collector Edition coupe owned 13 months
Sierra Nevada Torpedo IPA-currently on tap!Comment
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Re: R12 to 134 conversion
With respect to all, 134a is an excellent refrigerant and has been in use for many, many years. The myth that it does not perform well in ANY application is fed by the incorrect retrofit procedures used by those that don't know what needs to be done to insure that a system operates correctly. The oil used in our old cars is a simple but highly refined mineral oil. It is miscible with any CFC or HCFC like R12 and R22 but not with MOST others. When an automotive system is retrofitted ALL mineral oil must be removed. If it isn't the liquid refrigerant will deliver it to the evaporator where it will stay. Since it will not blend with 134a in the form of a vapor it can't be returned to the compressor where it should be. As a result the oil becomes an insulator and prevents cooling in the portion of the evaporator that is "oil logged". It's possible that a 20,,maybe 30% loss in capacity is due to oil logging which prevents heat transfer. I retrofitted the A/C in my '72 this spring, it works real nice, very cool. My situation is a little different though. I had no choice but to replace or rebuild every component except for the TXV, condenser which I properly flushed and had the POA rebuilt and calibrated for 134a. There is no doubt that all remaining mineral oil has been removed, probably the biggest problem for most. If done well 134a will be fine.Comment
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