AC Upgrade

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bobscuda67

bobscuda67

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I thinking of putting my AC system back together this winter and need some advice.
I have factory AC on my Barracuda and when the 273 was in it I completely resealed the RV2 and all new o rings, drier and expansion valve. I replaced the old condenser too.
Everything was changed over to R134. After it was all done the best vent temp I got out of it was 44 degrees.
Now I have the 340 with Magnum heads and a Magnum specific RPM intake so all the coolant hose locations are in the way of the RV2. And the support brackets won't fit. Not that I want to use it anyway.
I would like to use the small Sanden with the existing parts I have on hand to save some cash. Ill probably need to make a custom bracket to hold the compressor and the idler pulley.
I have manual steering so I have a bit more room on that side of the engine.
If I just swap out the compressor will the vent temps go down?
I know if I install a modern condenser the temps would go down. But by how much?
I do have two small cans of R12 that I've had for 30 years. Can the Sanden be charged with R12 and would that work better than the R 134?
 
Looks like the R12 in a Sanden is a no go. Since that's the case I'll need a new condenser for the R 134.
 
Just changing the compressor, probably will not lower the vent temps. That would happen, only if the new compressor had more pumping capacity then the old compressor. The RV-2 had plenty of pumping capacity, if in good condition. A new parallel flow condenser is a big improvement, and highly reccommended. The sanden can be used with R-12, but why? What are you going to do, if you have to recharge the system in the future.
Actually 44 degrees vent temp is not all that bad. Once the vent temps start getting lower then 40-41 degrees, you have a chance of evaporator freeze up. The surface of the evap, will be colder then the vent air temp. If the evap temp goes below 32 degrees, the moisture in the air will freeze on the evap, and start to restrict airflow. The clutch cycling sw, is supposed to prevent that from happening. The 44 degree temp, might be the switch setting, in which case changing any other component will not improve the vent temp.
 
The RV2 is in very good condition but I think where I went wrong is buying a replacement condenser and not a multipass condenser for the R134a.
I still want to replace the compressor to a Sanden model with the new condenser.
Thanks.
 
R-134 will never match the efficiency of the old R-12. You cannot mix refrigerants. Although production of Freon R-12 refrigerant was banned several years ago, there is plenty available. You would need to get all of the 134 refrigerant and oil completely out of the system. Reseal as you did before. Normally if you measure the vent temp, you would either have a large fan blowing through the condenser or drive the car at least 40 mph to get enough airflow through the condenser. Normally you could expect a max of a difference of a 25-30 Degree difference between the outside ambient temp and the inside of the car temp. If it is 100 degrees outside the a/c is not going to drop inside temps to much more than 70-75 degrees. I would use the Sanden compressor. You could get one with the proper mounting brackets from company's like Classic Auto air or Vintage Air and others. Just look on line and make some calls. The more efficient the cars cooling system is the better the air will work. If the car runs hot you need to address that problem before you do any a/c work.
 
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I use Duracool refrigerants in all my vehicles, even the 2002 T&C. Enviro-safe is another HC refrigerant. They work slightly better than R-12. Don't believe the "blows up" stories. Pretty absurd scientifically and no reported fire in millions of cars using HC for decades. Home refrigerators in Germany use HC refrigerant. Hella PAO 68 is the best oil today for any refrigerant. R-134A is being outlawed. The real concern is the poisonous gases produced when R-134A and R-1234yc burn. CO2 runs ~2000 psi and no retrofits for older systems.
 
I got my AC stuff out of storage this week. Its been sitting there since 2012.
The dryer and expansion valve were bought new in 12 and will be replaced again. The hoses are 1967 vintage and will be replaced also. My hard lines are in great condition and will be reused. The evaporator is factory but seams to be ok. I bought the condenser new in 12 and would like to reuse it if possible.
With 134 I'll have to use a multipass condenser for sure to get the best efficiency out of my old system. Would it still be advisable to change out the condenser with the Duracool also?
I'd like to reuse it but I guess I could sell it.
Thanks for the help!
 
MoparLeo said:
R-134 will never match the efficiency of the old R-12. .
Click to expand...

This is something that few people understand. There IS a difference between refrigerants for efficiency. Ammonia is another that is very efficient, and most likely why it is STILL USED in some large plants such as food processing, etc.

Other things people don't realize.........When R12 and later "the others" was first invented, there was a LOT of obstacles, and "they" (us) thought we/they had the world by the tail

BEFORE R12, home refrigeration had crap like Methyl Chloride or Sulfer Dioxide, both had their own problems and was HIGHLY toxic. And then of course there's ammonia which is NOTHING like what you buy "in a bottle" from the store

In contrast, R12 was fairly non toxic (until run through flames) there were oils that played well, it was efficient, did not require ridiculous operating pressures and temperatures (EG R22 is typically 250 psi or more for AC on a warm day and 410A is about DOUBLE that)

It was non-flammable, except for the oils, and if it weren't for that pesky environmental "deal" we'd all still be using the stuff
 
BillGrissom said:
I use Duracool refrigerants in all my vehicles, even the 2002 T&C. Enviro-safe is another HC refrigerant. They work slightly better than R-12. Don't believe the "blows up" stories. Pretty absurd scientifically and no reported fire in millions of cars using HC for decades. Home refrigerators in Germany use HC refrigerant. Hella PAO 68 is the best oil today for any refrigerant. R-134A is being outlawed. The real concern is the poisonous gases produced when R-134A and R-1234yc burn. CO2 runs ~2000 psi and no retrofits for older systems.
Click to expand...
Bill, I'm not going to get into a argument about Duracool, etc. But R-12 is just as bad, if not worse then r-134a and R-1234yc, when it comes in contact with open flame.
As for R-134a being outlawed, show me documentation to that effect. It just ain't so. It is being replaced by other refrigerants, but it will still be readily available. R-12 was not outlawed in the states (other countries, it was), it just can't be manufactured, or imported into the states. Existing supplies can still be used. No such stipulation on R134a.
One other point. If you use any refrigerant other then R-12 or R134a in any new or rebuilt auto a/c compressor, and have a failure, the manufacture/rebuilder, will not warrenty the compressor. In other words you pays your money and takes your chances
 
The U.S. date for R-134A phase-out keeps shifting. Back in 2014, it was supposedly 2017, but current rule is that light duty vehicles produced after 2020 cannot use it. It has been outlawed since 2011 in Europe. But, production and import will still be allowed, so it should be available afterwards, though states may have varying laws (ex. CA currently has $10 deposit on R-134A cans). For more, see Does R-134a Have a Phase Out Date? - Refrigerant HQ
The only good alternative is a HC refrigerant. Many U.S. cars will use HO-1234yc, but currently ~10x the cost of R-134A. In 2012, M-B performed simulated accident tests (punctured hose, impinging on hot turbocharger) and found that it burned and produced dangerous hydroflouric acid, which etched the windshield (bad for your cornea), and then fussed with France when they shipped cars w/ outlawed R-134A. While many refrigerants don't burn well, there are oil drops in the spray which do ignite well. See Coolant safety row puts the heat on Europe's carmakers

I don't know how a rebuilder could know what refrigerant you used, since they all evaporate quickly. They could fuss over the oil, but I doubt they would take the time to test it, and PAO 68 is compatible with all refrigerants. Anyway, I never consider warranties worth the paper they are printed on. Most rebuilders are going to claim "improper installation", regardless, if you are a onesy customer. They will only try to do good for a high-volume buyer.
 
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If you read the "snap" regulations about Duracool and other brand names of the same product, it is only legal as a direct replacement for R-134a, (not R-12). Technically a R-12 system must be retrofitted to R-134a, then it can legally be retrofitted to "R-12a". Also It is required to use unique charge fittings, for each refrigerant. How many people change the fittings?
You stated "phase-out" of R-134a. That is correct. Phase-out for new vehicles, not outlawed, for use in other vehicles, or manufactured, or sold.
As far as flamability, just about any refrigerant has an issue, even CO2. Even if the refrigerant does or does not burn, the oil mist that is carried out in a major leak can ignite.
This is an older thread, but check it out. Red Tec 12a legal or illegal? - Automotive Air Conditioning Information Forum
I have been doing A/C and ref work since the late 1960's, and have stated my position, on this subject several times. I suggest people research it for themselves.
I'm done, with this thread.
 
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