A/C Retrofit

[breeaad]

I have done automotive AC for a long time . It has been my experience that quickie cans of stuff don't work very well, for very long. The compressors always grind themselves up and they all leak,134-A is able to seep past R-12 seals and ,hose.
Most of our cars were designed for R-12, They have single barrier hoses, smaller condensers, different desiccant in the dryer/accumulator, and use 5w5 mineral oil.
134-A systems use different seals and hose. The compressors have heaver valves and swash plates.They use a bigger condenser. and run at higher pressures, It also requires a synthetic oil called PAG oil.
To do a proper AC conversion will run over $1000 to $1500 .
I do about fifteen a month and that's just about right on . (fords & some foreign cars are even more )
I kept R-12 on my own car when I changed over to a serpentine drive system.
There is no such thing as a magic fix in a can that will perform like a properly done conversion.

I am sure you are correct on most of your statements, but I will say this: R134 leaks past the correct seals much faster than R12 due to the molecular make-up. When I went through licensing for AC service back in 1997, I was told that R134 systems would need to be recharged every 2-3 years. My experience says that is about right. But R12 could go a decade.
I have used R12 and 134, I have mixed them, and I have used generics (be-cool). I have never had a compressor failure. My olds has had be-cool in it for 15 years on the factory compressor and still no issues. So why spend 1000-1500 on a complete swap? I mean, if the refrigerant trashed the entire system that would be the repair bill. So why not chance it? I do draw the line at propane, however.

Well you are the lucky one, Here in Arizona The system has to be 100% to work.
When It's 119 in the shade and 80% humidity Your Be-cool just won't cut the mustard, it just won't transport the lubricant throughout the system. .
You have not seen any compressors chew them selves up, then you haven't been doing AC repair very long.
Out here high side pressures on a proper R-12 or 134 A system can exceed 375-450 lbs ,causing ring and valve failure in any compressor. In most GM cars this plugs the orifice tube.
If you check the EPA web site on auto AC retrofitting , They don't even recognise Be-cool . as a viable "drop in replacement
So I wish you all the best and I hope you learn more about what you are talking about , Maybe You can take some courses at night school on basic physics and basic refrigeration theory.
I am attaching a picture of a good orifice tube ,with a plugged tube covered with the gut's of a compressor from a "cheapo retro-fit"

I apologize that my tongue in cheek comments offended you. I was merely poking fun at all the "what not to do" things that have worked in the past. Hence, the propane comment. I thought it was obvious.

But you shouldn't make the assumption that I am uneducated. I have a degree in Mechanical Engineering from a top-ten engineering school. I have had classes in physics, thermodynamics, heat and mass transfer, fluid dynamics, and theory of energy systems. I do know what I am talking about.

The job where I worked on AC was a college job and was put on AC because it is one of the easiest areas of automotive repair, and I was green. You have machines that pull the vacuum, leak check, identify leak locations, and test for compressor efficiency and basic system issues. You have books to tell you what oil and charge to use, where the orfice/expansion valve is, and how to test the high/low pressure cut-outs. The most difficult part about AC repair is changing the evaporator on certain vehicles with an in-dash core.

I feel for you working on these systems in AZ. You know better than anyone that when it gets that hot outside, the Stirling cycle has to be to be working perfectly to make the customer happy.

 

[tc1959]

Sorry breeaad: but I just get tired of all the miss information out there. I spent a lot of time at the GM desert Proving Grounds.
We did heat trials on just about every kind of car built back around the time GM switched to 134-a (91-94)

We punished every component of a AC system, Our team developed a standardised recovery system ( with the people from Robinare) that would, become the standard recovery machine that every GM dealer now has as a required tool.(Kent-More)

We did hot testing on every type of possible refrigerant known to man at that time.
Now after all these years I just get pissed when a customer goes and has a Quickie conversion done and gets screwed for $800 - $1500 for a crap retrofit . Then we have to take it all off and start over.
(flushing all the old 5w5 oil out of every component)
Replacing the accumulator/dryer,installing new or rebuilt double barrier hoses, new Nitrile o-rings,and a new 134 rated compressor, With the proper oil.
( I highly recommend Vintage air kits because all the proper engineering has been done.)

I have seen a Propane based retrofit that exploded and actually killed a woman riding in a 88 Eldorado.
I will admit I don't know if some of these Quickie deals will work, If you live where the weather is moderate.Maybe you will get lucky.

 

[Kutdoctor2k11]

Doing a lil bit of looking around i found this

http://www.zirgo.com/catalog/Air-Condit ... ost-System

I'm a little drawn back by the price but it claims to work on all vehicles and its starting to heat up around here

 

[79loserbluebu]

for a informative thread.

Will R12 accumulators, evaporators and condensors be alright with R134a? When converting a system to R134a, are there specific o-rings that you use on your older style condensors, evaps, and driers?

I just started a thread asking about the accumulator differences between a 79' Malibu, and one from an 87' Monte Carlo, the differences being the high pressure side inlet pipe is on the inside on the later, as well as an attached clutch cycling switch. When converting to R134a, www.rockauto.com shows there is two different switches. Do the switch both screw into the same point, or is the R134a switch on one of the lines?

Also, when going with a custom A/C setup, how do you know how much to actually charge the A/C system to the right amount? By looking at the high and low side pressures? Or is there a special formula for this?