New Condenser with 134a Conversion

[Guest Pearville]

Been reading up on converting to 134a for my 63 Riv. Some general A/C threads say that the original condenser is not right for 134 and you need to install a new parallel condenser. If anybody has experience with this conversion please share. I have read the tech tips on the subject at ROA but it doesn't specifically address the condenser. Thanks

[TexRiv_63]

People who want to sell new parts will tell you that you HAVE TO change all kinds of stuff. If you are restoring a car and building a whole new system that may make sense but not if you are just converting a driver. I had the system on my 63 Starfire done more than two years ago. The only parts that were changed were the charge fittings, receiver dryer, oil, and refrigerant, everything else is original 1963. I think it cools quite well and I also live in Texas!

[JZRIV]

The question of converting 1st gen Riv A/C to 134A came up at the ROA national meet Tech Q&A session in Lexington last week. Overwhelmingly the consensus is to stay with R12 for many reasons. The price has come down and its easier to get now than it has been for 20 years due to low demand. 134A simply does not cool as well especially if you live in a hot climate like TX where the system requires peak perfomance. Some have converted and are happy but they seem to be the exception. There are alot of variables to consider.

I definitely wouldn't change the condenser.

[1965rivgs]

Changing the condenser to an improved design compensates for the difference in characteristics between R12 and 134. It would surely improve performance but the question is "Is it necessary?" Charging your original system with 134 will result in cooling (assuming everything is in order) but whether it is satisfactory or not depends on many factors including the user. Try it if R12 is not an option...if it doesnt satisfy move on from there. In the very least you will know if your system components are sound and the system will hold pressure/charge. Keep in mind the original STV valve is adjustable, allowing a limited adjustment of evaporater pressure and consequently evaporater/outlet temp. Good luck,

Tom Mooney

[Guest Pearville]

Thanks for the info guys. I think I will check for R12 prices and go from there. Being from Texas A/C is not really a luxury and it has to work pretty well. It's cooler today than all week it's only 91 today. Thanks again for your help

[Jim Cannon]

Don't waste your time talking to auto parts stores. They have crazy high retail prices on R-12.

Look for R-12 on CL and on eBay. Lots of people have cans that they squirreled away long ago "in case I need it" and have now decided they don't. I found 25 lbs on Houston CL from a private individual not that long ago. Save on shipping.

The "EPA certificate required" text on eBay is just to keep the Feds and eBay police off their back. They don't care if you have one or not, as long as you are prepared to pay $$$.

Put dye in your system (get at auto parts store -- no certificate required, I don't care what the counter guys says) and look for leaks with UV light.

Expect it to leak some at the compressor shaft seal. Not much you can do about it. Ironically, the more you run the compressor, the less that shaft seal leaks. So run it for a few minutes even in the winter when you don't need it.

It would not hurt to replace the high pressure hot gas hose now, from compressor to condenser, before charging. The heat deteriorates the hose and the high pressure on that hose makes it leak first.

Only replace the other hoses of you see evidence of leaking (oil stain).

If your STV is sticking, get it rebuilt or replace it with a compressor cycling pressure switch assembly. A stuck STV will just freeze up the evaporator into a big block of ice and give you no cooling at all. The vacuum modulator valve in the dash must also be working to not have evaporator freeze up. Test with a vacuum gauge. Details in shop manual.

Poor thermal transfer efficiency of original stock condenser, due to age, is often the cause of poor cooling with R-12 or R-134a. If the liquid line coming off the condenser is very warm, you are not cooling the freon enough.

Also check the fan clutch and consider replacing it. They don't cost much and can make a big difference in A/C system performance. You must use the one with the little coil spring on the front face. Imperial #215049.

My '63 Riv blows 35 degree air with R-12. I have driven it through AZ in the summer and been comfortable.

The next thing you will be replacing is the radiator... stock 3-row cannot handle Houston in the summer with A/C on. Get a 4-row and be happy.

[RivNut]

Jim,

Great piece, thanks for all you do.

You're a real asset to the ROA.

Ed

[Guest Pearville]

Thanks Jim,

At time of purchase and now my system is apart. A rebuilt compressor, new hi pressure hose and dryer came with the car. I have been doing my research so my mechanic will know which way i want to go. He says he has not had good luck with 134 in the old systems in Texas heat. I have already looked on Ebay for R12 and seen some ok prices. The radiator suggestion is a great suggestion, I hate overheating cars.

I think you should put a title on this post and put it in Tech Tips for those who are bringing A/C's back from the dead. I have not found this much specific info. in one place in all my research, and I'm a pretty good researcher. Thank you so much for taking the time and hopefully saving me a bundle.

Mike

[Guest Pearville]

I'm staying with R12, new radiator, and play it from ear.

Thanks

[1965rivgs]

Just some observations here...R134 in a system designed for R12 may not prove satisfactory in high load locations like Phoenix, Texas, Florida, etc...especially in an older system which may have other problems like air flow and sealing issues, warm air leaking into the cab past poor wstrip,etc... It will provide cooling but might not be enough...but R134 IS an acceptable alternative to R12 in most locations and in properly operating systems.

I live and work in the Chicago area, we experience some hot and humid weather, and I have done MANY conversions from R12 to R134 with satisfactory results. I have been doing such conversions since the transition was made in our industry almost 20 years ago. I have been a professional tech for about 35 years now and dont need to fall back on second hand info or internet chatter...my experience is first hand and hands on!

Case in point...I currently own and operate two `85 Rivieras. One is a beater I shot full of R134 because the R12 can was in the barn and I was in too much of a hurry to fetch it... and the other is a 22K mile car which I serviced with R12 before driving it to the ROA annual meet. There is only a very small difference in the R12 car versus the R134 car. These cars are otherwise identically equipped. Most people would not even notice the difference. As to the size of the molecules, blah, blah, blah...the R134 is holding the charge very nicely and I charged it two seasons ago. It may at this point need to be topped off, I havnt put gauges on it since I serviced it, but it cools nicely and I expect it will continue to do so for at least the duration of this summer.

R134 does operate at higher pressures but the pressures are not that much higher, especially if one pays attention to airflow across the condenser with a proper shroud or a supplemental cooling fan when not underway. The original R12 hoses will handle it...unless, of course, the hose is already compromised.

It`s easy to get misled by the minutia of comparisons between R12 and R134 and their properties but the "proof is in the pudding"..the doing of it and not in the talking about doing it. Based on my experience as a tech with R134 over the last decade and a half, R134 will prove an acceptable alternative to R12 except in the most extreme conditions.

BTW...dont grasp the high pressure line exiting the condenser and expect it to be cool. If the system is operating under heavy load the line will be very hot, this is normal. This is not an indication the condenser is compromised. The perceptible cooling, to the touch, in any automotive AC system, takes place where the system transitions from high to low pressure, which in the case of the first gen Riv, is the expansion valve/evaporator core. In modern cycling systems it is at the orifice tube/ evap core. Stay cool!

Tom Mooney

Edited July 6, 2013 by 1965rivgs (see edit history)

[Jim Cannon]

BTW...dont grasp the high pressure line exiting the condenser and expect it to be cool. If the system is operating under heavy load the line will be very hot, this is normal. This is not an indication the condenser is compromised. The perceptible cooling, to the touch, in any automotive AC system, takes place where the system transitions from high to low pressure, which in the case of the first gen Riv, is the expansion valve/evaporator core.

I agree, Tom, and did not mean to imply that the high pressure liquid line coming out of the condenser should be cold to the touch, like you will get in the car. But it should be much cooler than the temperature of the line going into the condenser, if the condenser is doing its job. One of those IR guns should help you judge that.

[TexRiv_63]

Just some observations here...R134 in a system designed for R12 may not prove satisfactory in high load locations like Phoenix, Texas, Florida, etc...especially in an older system which may have other problems like air flow and sealing issues, warm air leaking into the cab past worn wstrp. It will provide cooling but might not be enough...but R134 IS an acceptable alternative to R12 in most locations and in properly operating systems.

Tom Mooney

Good points Tom. When I first had my 63 Olds converted the system cooled but not great, I put it down to all the stock reasons you hear over and over. Then when I had to remove the steering column to replace the rag joint I had a good opportunity to look under the dash. I found that the drivers side dash outlet was completely disconnected from the hose! After fixing that I also noticed that the plastic feed ducts for the outlets had three locations on the bottom where holes were to provide flow to your feet. That seemed like a lot of air to siphon off so I covered two of those locations with duct tape. Suddenly the system worked a LOT better. I still have the problem of bad window weatherstripping letting in warm air which I need to fix, I'm sure that will improve cooling further. These are things to look at with either R12 or R134.

[Guest Pearville]

Again thanks to you all. Sounds like any of the systems and refrigerants work fine, its what you are comfortable with in the climate you are in. I like Jim's idea of beefing up the cooling system to insure good operating temps and I am finding that the R12 is not prohibitably expensive anymore. I will let you guys know how it works out.