A/C 134A conversion in my 1969
02-17-2018, 03:38 PM
#1
Melting Slicks
Thread Starter
A/C 134A conversion in my 1969
I want to "upgrade" my system, which never worked that great, to 134a.
I want to buy a new evaporator and condenser. Are all these the same meaning the'll work with both refrigerants? In other words, I don't have to look for a 134a evaporator/condenser right? Would you recommend me getting a strictly 134a compressor or can I get my original R12 compressor rebuilt for 134a use? I sorta like the looks of that big old black unit. Thanks as always, Fred.
I want to buy a new evaporator and condenser. Are all these the same meaning the'll work with both refrigerants? In other words, I don't have to look for a 134a evaporator/condenser right? Would you recommend me getting a strictly 134a compressor or can I get my original R12 compressor rebuilt for 134a use? I sorta like the looks of that big old black unit. Thanks as always, Fred.
02-18-2018, 07:19 AM
#2
Burning Brakes
I would be interested in the reply's too for my 78.
02-18-2018, 07:21 AM
#3
Ah, it must be spring. The annual AC questions are here.
Systems designed for 134a have an evap with a different sized orifice/TXV and a condenser with more ability to shed heat (more fins/tubes).
That being said, 134a will work in a R12 system, it is just not optimized for it. 134a in a R12 designed system typically runs at higher pressures so a pressure safety switch will typically kick in often causing the compressor to cycle a lot. Also, 134a does not have quite the same ability to cool as R12 when used in a R12 designed system so your vent temps will not likely get as cold as they would with R12.
The real issue with 134a in a R12 system is the oil. Oil used with an R12 system will not circulate with 134a refrigerant so your compressor will quickly die. If you insist on using the old R12 compressor at least bench drain the oil and replace with the proper 134a oil.
If you do as you suggest above and swap out the condenser and evap for 134a specific models and then change the oil for your old compressor you should be fine and have adequate temps at the vent. Make sure to change out the accumulator/receiver/dryer too as oil will accumulate in there.
On other R12 cars I have I typically counter all that by using a mix of 134a and propane with the original R12 components. Propane is a great refrigerant and being a hydrocarbon it will also carry the original R12 oil. Propane is sold in refrigerant cans labeled as '12a' or 'retrofit refrigerant'. Anything where the MSDS says "hydrocarbon" or "68476-85-7" or "petroleum based" or "flammable" or "petroleum gas" or "petroleum distillate" or "Alkanes" or "R290" will be propane or a propane/butane mix. Redtek 301 is an example but there are many others selling. 2-6 oz cans of Propane for $20 leads to a lot of companies selling it. (YouTube for how to fill from your BBQ grill tank)
The propane charge is so small there is no risk of an explosion. The EPA approved propane as a refrigerant in household dorm/wine coolers 3-4 years ago. I typically run 1 can of propane and top off the balance with 134a, but you could run the whole system with propane if desired (almost all modern refrigerants are blends, and almost all contain a squirt of propane). Note that 134a does not like to be overfilled like you can with R12 so fill to the low end of the scale for best cooling.
Lots and lots of past threads on this topic. Here is one...
https://www.corvetteforum.com/forums...big-block.html
Systems designed for 134a have an evap with a different sized orifice/TXV and a condenser with more ability to shed heat (more fins/tubes).
That being said, 134a will work in a R12 system, it is just not optimized for it. 134a in a R12 designed system typically runs at higher pressures so a pressure safety switch will typically kick in often causing the compressor to cycle a lot. Also, 134a does not have quite the same ability to cool as R12 when used in a R12 designed system so your vent temps will not likely get as cold as they would with R12.
The real issue with 134a in a R12 system is the oil. Oil used with an R12 system will not circulate with 134a refrigerant so your compressor will quickly die. If you insist on using the old R12 compressor at least bench drain the oil and replace with the proper 134a oil.
If you do as you suggest above and swap out the condenser and evap for 134a specific models and then change the oil for your old compressor you should be fine and have adequate temps at the vent. Make sure to change out the accumulator/receiver/dryer too as oil will accumulate in there.
On other R12 cars I have I typically counter all that by using a mix of 134a and propane with the original R12 components. Propane is a great refrigerant and being a hydrocarbon it will also carry the original R12 oil. Propane is sold in refrigerant cans labeled as '12a' or 'retrofit refrigerant'. Anything where the MSDS says "hydrocarbon" or "68476-85-7" or "petroleum based" or "flammable" or "petroleum gas" or "petroleum distillate" or "Alkanes" or "R290" will be propane or a propane/butane mix. Redtek 301 is an example but there are many others selling. 2-6 oz cans of Propane for $20 leads to a lot of companies selling it. (YouTube for how to fill from your BBQ grill tank)
The propane charge is so small there is no risk of an explosion. The EPA approved propane as a refrigerant in household dorm/wine coolers 3-4 years ago. I typically run 1 can of propane and top off the balance with 134a, but you could run the whole system with propane if desired (almost all modern refrigerants are blends, and almost all contain a squirt of propane). Note that 134a does not like to be overfilled like you can with R12 so fill to the low end of the scale for best cooling.
Lots and lots of past threads on this topic. Here is one...
https://www.corvetteforum.com/forums...big-block.html
Last edited by Dynra Rockets; 02-18-2018 at 07:30 AM.
02-18-2018, 07:21 AM
#4
Melting Slicks
I upgraded my 69 to 134. Ecklers has a updated compressor that looks a lot like the original. You'll also need a POA valve and a dryer. If your system is intact have it checked for leaks. I'm still using the original condenser [part in front of radiator] also not an A/C expert. Check all your hoses for cracking, replace as necessary [ask me why I suggest this]. Any fitting that has O-rings, they need to be changed to the green O-rings. When changing the POA and you can't get any wrenches on the large nuts, contact me, I have a solution. T
02-18-2018, 10:51 AM
#5
Le Mans Master
For the condenser an R-12 condenser will work, just not as well as a parallel flow condenser (134a). Electric fans can make the difference between meh cold air and good and cold air with the old R-12 condenser while using 134a.
As far as oil goes it's like this
Mineral oil = R-12
PAG oil = 134a
ester oil = r-12 or 134a
Do not mix PAG and mineral oil as it can clog up orificies and tend to turn to a gel like consistency.
Since ester oil is compatible with the other two then if you are not flushing the system to get rid of all mineral and changing the hoses for a PAG conversion, ester would be the oil to use.
Ester is what I use in my system that still uses all the original r-12 components, including the pump but now with 134a refrigerant.
My late 77 system already had an orifice tube system vs the old POA system so I did not need to change anything there other than the actual orifice itself.
The refrigerants themselves can be mixed (chemically) not necessarily legally. As recovery would not make the refrigerant not re-usable do to the mix. So up to you on that.
As far as oil goes it's like this
Mineral oil = R-12
PAG oil = 134a
ester oil = r-12 or 134a
Do not mix PAG and mineral oil as it can clog up orificies and tend to turn to a gel like consistency.
Since ester oil is compatible with the other two then if you are not flushing the system to get rid of all mineral and changing the hoses for a PAG conversion, ester would be the oil to use.
Ester is what I use in my system that still uses all the original r-12 components, including the pump but now with 134a refrigerant.
My late 77 system already had an orifice tube system vs the old POA system so I did not need to change anything there other than the actual orifice itself.
The refrigerants themselves can be mixed (chemically) not necessarily legally. As recovery would not make the refrigerant not re-usable do to the mix. So up to you on that.
Last edited by REELAV8R; 02-18-2018 at 10:52 AM.
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02-19-2018, 06:09 PM
#6
Melting Slicks
Thread Starter
Ah, it must be spring. The annual AC questions are here.
Systems designed for 134a have an evap with a different sized orifice/TXV and a condenser with more ability to shed heat (more fins/tubes).
That being said, 134a will work in a R12 system, it is just not optimized for it. 134a in a R12 designed system typically runs at higher pressures so a pressure safety switch will typically kick in often causing the compressor to cycle a lot. Also, 134a does not have quite the same ability to cool as R12 when used in a R12 designed system so your vent temps will not likely get as cold as they would with R12.
The real issue with 134a in a R12 system is the oil. Oil used with an R12 system will not circulate with 134a refrigerant so your compressor will quickly die. If you insist on using the old R12 compressor at least bench drain the oil and replace with the proper 134a oil.
If you do as you suggest above and swap out the condenser and evap for 134a specific models and then change the oil for your old compressor you should be fine and have adequate temps at the vent. Make sure to change out the accumulator/receiver/dryer too as oil will accumulate in there.
On other R12 cars I have I typically counter all that by using a mix of 134a and propane with the original R12 components. Propane is a great refrigerant and being a hydrocarbon it will also carry the original R12 oil. Propane is sold in refrigerant cans labeled as '12a' or 'retrofit refrigerant'. Anything where the MSDS says "hydrocarbon" or "68476-85-7" or "petroleum based" or "flammable" or "petroleum gas" or "petroleum distillate" or "Alkanes" or "R290" will be propane or a propane/butane mix. Redtek 301 is an example but there are many others selling. 2-6 oz cans of Propane for $20 leads to a lot of companies selling it. (YouTube for how to fill from your BBQ grill tank)
The propane charge is so small there is no risk of an explosion. The EPA approved propane as a refrigerant in household dorm/wine coolers 3-4 years ago. I typically run 1 can of propane and top off the balance with 134a, but you could run the whole system with propane if desired (almost all modern refrigerants are blends, and almost all contain a squirt of propane). Note that 134a does not like to be overfilled like you can with R12 so fill to the low end of the scale for best cooling.
Lots and lots of past threads on this topic. Here is one...
https://www.corvetteforum.com/forums...big-block.html
Systems designed for 134a have an evap with a different sized orifice/TXV and a condenser with more ability to shed heat (more fins/tubes).
That being said, 134a will work in a R12 system, it is just not optimized for it. 134a in a R12 designed system typically runs at higher pressures so a pressure safety switch will typically kick in often causing the compressor to cycle a lot. Also, 134a does not have quite the same ability to cool as R12 when used in a R12 designed system so your vent temps will not likely get as cold as they would with R12.
The real issue with 134a in a R12 system is the oil. Oil used with an R12 system will not circulate with 134a refrigerant so your compressor will quickly die. If you insist on using the old R12 compressor at least bench drain the oil and replace with the proper 134a oil.
If you do as you suggest above and swap out the condenser and evap for 134a specific models and then change the oil for your old compressor you should be fine and have adequate temps at the vent. Make sure to change out the accumulator/receiver/dryer too as oil will accumulate in there.
On other R12 cars I have I typically counter all that by using a mix of 134a and propane with the original R12 components. Propane is a great refrigerant and being a hydrocarbon it will also carry the original R12 oil. Propane is sold in refrigerant cans labeled as '12a' or 'retrofit refrigerant'. Anything where the MSDS says "hydrocarbon" or "68476-85-7" or "petroleum based" or "flammable" or "petroleum gas" or "petroleum distillate" or "Alkanes" or "R290" will be propane or a propane/butane mix. Redtek 301 is an example but there are many others selling. 2-6 oz cans of Propane for $20 leads to a lot of companies selling it. (YouTube for how to fill from your BBQ grill tank)
The propane charge is so small there is no risk of an explosion. The EPA approved propane as a refrigerant in household dorm/wine coolers 3-4 years ago. I typically run 1 can of propane and top off the balance with 134a, but you could run the whole system with propane if desired (almost all modern refrigerants are blends, and almost all contain a squirt of propane). Note that 134a does not like to be overfilled like you can with R12 so fill to the low end of the scale for best cooling.
Lots and lots of past threads on this topic. Here is one...
https://www.corvetteforum.com/forums...big-block.html
Last edited by TWINRAY; 02-20-2018 at 01:09 PM.
02-20-2018, 01:02 PM
#7
Melting Slicks
Thread Starter
For the condenser an R-12 condenser will work, just not as well as a parallel flow condenser (134a). Electric fans can make the difference between meh cold air and good and cold air with the old R-12 condenser while using 134a.
As far as oil goes it's like this
Mineral oil = R-12
PAG oil = 134a
ester oil = r-12 or 134a
Do not mix PAG and mineral oil as it can clog up orificies and tend to turn to a gel like consistency.
Since ester oil is compatible with the other two then if you are not flushing the system to get rid of all mineral and changing the hoses for a PAG conversion, ester would be the oil to use.
Ester is what I use in my system that still uses all the original r-12 components, including the pump but now with 134a refrigerant.
My late 77 system already had an orifice tube system vs the old POA system so I did not need to change anything there other than the actual orifice itself.
The refrigerants themselves can be mixed (chemically) not necessarily legally. As recovery would not make the refrigerant not re-usable do to the mix. So up to you on that.
As far as oil goes it's like this
Mineral oil = R-12
PAG oil = 134a
ester oil = r-12 or 134a
Do not mix PAG and mineral oil as it can clog up orificies and tend to turn to a gel like consistency.
Since ester oil is compatible with the other two then if you are not flushing the system to get rid of all mineral and changing the hoses for a PAG conversion, ester would be the oil to use.
Ester is what I use in my system that still uses all the original r-12 components, including the pump but now with 134a refrigerant.
My late 77 system already had an orifice tube system vs the old POA system so I did not need to change anything there other than the actual orifice itself.
The refrigerants themselves can be mixed (chemically) not necessarily legally. As recovery would not make the refrigerant not re-usable do to the mix. So up to you on that.
02-20-2018, 01:10 PM
#8
Team Owner
If you are dead set on R134 and will be replacing the condenser and evaporator than I would go with a new modern AC pump vice the old A6.
Now having said that I would have no problem keeping this AC system OEM and going back with R12 but I'm funny like that.
Now having said that I would have no problem keeping this AC system OEM and going back with R12 but I'm funny like that.
02-20-2018, 01:31 PM
#9
Burning Brakes
Member Since: Aug 2013
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There is a R-12 / R-134 oil out that says it will mix with either system.
SUPERCOOL is the name and is also supposed to cut down the corrosion, which I see as RUST.
The old A6 was probably the toughest compressor ever built. New ones are a bit different using teflon rings and la lip seal.
I would keep the original compressor and post in 40 years to let us know how it's working.
Dom
SUPERCOOL is the name and is also supposed to cut down the corrosion, which I see as RUST.
The old A6 was probably the toughest compressor ever built. New ones are a bit different using teflon rings and la lip seal.
I would keep the original compressor and post in 40 years to let us know how it's working.
Dom