If you have a RV2 compressor on your car (factory AC), and AC works . . .would you leave it alone ?? (system already changed to R134) or would you go to the newer rotary style compressor (takes less hp to run, less weight on front of engine, etc. . . ) . . .

If it ain't broke don't fix it....

Or my favorite, if it ain't broke, you're not trying!

I am just too much of an anal purist. I'd stick with the original. The only thing I would question is if the shaft seal is compatible with R-134A.

That is great question on the shaft seal . . . I guess I should not complain, I finished the car in 2013 (and have put on 10k miles) and now I see evidence of pag oil on the front of the compressor, so time for the shaft seal to be replaced . . . hence the question, just do the seal (ones today say compatible with R134), or convert to the Sanden rotary . . . but as you say, its all there in place and nothing else wrong . . . probably order up the shaft seal and talk to my local AC shop . . .

If it was working and my engine bay was as pretty as that one--no way I would tear it apart to fix some thing that wasn't broken.

If it starts to go, then maybe I would look at some options.

I remember turning on the AC on my RV2 cars, and it was like their 383s were lighting off a Harley.
My rotary-compressor cars (GM stuff) were noticeably smoother in operation.
But for an original car, I wouldn't change it unless I had to use the AC often and for extended periods.
If I had a "driver" car with some other mods, I'd update the AC without regret.
OR -just save the old stuff, and except for car shows, you're fine.
But if the RV2 doesn't bother you & it's not broken, take my opinion with a large dose of salt, as the saying goes...

Keep in mind that you need to install a clutch cycling switch if you use other than the RV2 compressor.

[quote=John_Kunkel]Keep in mind that you need to install a clutch cycling switch if you use other than the RV2 compressor. [/quote

Why is that?]

If I had a functional RV2 setup, I'd simply repair it.

Especially on a driver or cruiser.

If I was building from scratch a full function touring car I would go newer. But that would be accepting that everything is going to be custom.

The RV2 will pump more gas than the sanden by a reasonable percentage, leave it alone...

Is that a propane converter behind the battery?

The system will freeze up. The RV2 has a valve that keeps that from happening.

No, that factory cruise control transducer

If it works I'd leave it alone, only benefit is weight reduction.
Here's info from when I converted over

Shaft seals on AC Compressors are not lip seals like you would see on a low pressure seal like a main seal. They are a type of seal that looks a lot like the seamless ring seals in a transmission.

They should be R134a resistant because they are not rubber. Side note: Never handle a compressor seal with your hands. According the manufacturers, it ruins them.

I have converted a lot of systems over to R134a and I have not had a leak at the compressor shaft seal.

All have leaked down over time much faster than an R12 system would. It may be the smaller molecules escaping through the hoses not designed for R134a or the fact that R134a tends to run higher pressures and the result is small leakage.

Mineral oil was used in R12 systems. Mineral oil will not carry in R134a so it settles in the bottoms of the compressor, drier, and cores. So you will need to change the oil or at least run Ester oil. PAG and Mineral oil are not compatible together.

Fill your system by pressure not the quantity, books will tell you 80% R134 to what the original R12 system used but that is usually too much. Pressures are temperature dependent.

All that said I have no problem using the old system if I want it to look stock but it will never cool as good as a properly functioning R12 system.

If you want the absolute best using R134a gas, then install a matched component system made for R134a.

My

Can you still drive into Canada or Mexico and get it recharged with R12? Asking for a friend

From what I have they refill it with Propane. Rumor has it..

Propane is an excellent refrigerant. It's just against the law to use it in a car, but so is speeding and they don't have a radar gun for propane. LOL

Around here, little cans of R12 go for about $20 each. Seems like no big deal unless you have a leaker.

I am in Canada . . . and it's all R134 up here, as far as I know. When I put the car together, all AC components were NEW, with R134 compatible hoses, seals, etc . . .

Same here. A scratch build would see (you would have to squint) a sanden mounted under the alternator where the fuel pump used to be.

Ever wonder why it's against the law? Propane is highly flammable and anything that breaks a line and can ignite it then you have a fireball under your hood! R134 uses a higher operating pressure than does R12. So if the time comes where you might need to do some work to the ac system it's wise to use a compressor that is made for 134a. If you have a 6 pack or hemi the choice is simple because you don't have the option.

If the advantages of the new compressor attract you so much, you can change it. But I don't recommend it. First of all, remove the exhaust manifold from the engine. After that, loosen the generator belt and release the compressor pulley. Next, an external inspection of the compressor is performed, and the freon circulation tubes are removed. After that, pull out the plug with the wires from the compressor connector and unscrew the nuts of its fastening. Remove the old compressor, and install a new one in its place. But in general, I don't advise you to do it yourself. It's better to find affordable and reliable aircon service.

You have an expansion valve that regulates low side pressure and temperature, thus no need for a clutch cycling switch. Low side clutch cycling switch is necessary with a CCOT system.(Clutch Cycling Orifice Tube).
You do need, and probably already have, a high-pressure compressor cut-off switch normally mounted on the receiver/drier.

The RV2 contains the oil to lubricate the compressor in the crankcase of the compressor; just like the gas engine under the hood. There's a drain plug on the bottom of the compressor oil pan for changing the oil and there's a pipe plug on the side of the compressor that gets removed so you can use an RV2 oil dipstick to measure the oil level. The oil, whether it be mineral, PAG or Ester, does not circulate with the refrigerant in an RV2/R-12 system like a rotary/134a compressor system, regardless of the refrigerant you choose to use.

Keep this in mind: The receiver/drier that is meant for an R12 system is usually not designed to retain and meter oil like a receiver/drier that is meant for a 134a system and a later style compressor.

Any of the three oils should work on the RV2 as long as you add it to the crankcase of the compressor and NOT the charging port. THE OIL DOES NOT MIX AND CIRCULATE WITH THE REFRIGERANT with an RV2 or York/Tecumseh.. Personally I would simply use mineral oil just like the factory did. The RV2 compressor has two roller bearings, a dinky crankshaft, two connecting rods and two pistons with rings. The crankshaft gets lubricated through a scoop/slash system.


The front seal is pretty easy to replace. It's typically retained by 4 small screws. No special tools required.

As said before . . . I put system together when I restored the car, and ensured it was using R134a seals, oil, etc . . . finally cranked up the car to start driving this summer - turned on AC, and within about 10 seconds, she was blowing arctic cold air . . . still works great ! . . .

I'm by no no means an AC system expert, but according to the service manual in an RV2/R12 system the oil does mix with and is carried by the R12 through the entire system.

I think he was referring to the RV2 twin cylinder compressor used on old Mopars. The majority of the oil sits in the sump splash oiling the Compressor like a lawn mower engine does.

Yes, you are correct that oil will circulate but it will not get into the sump through the hoses. With the RV2 compressor, putting oil in the hoses is like adding adding oil to a lawn mower engine through the carburetor.

Because it will circulate, you should also add some to the system in the drier when installing everything from scratch to lubricate the other parts. i.e. compressor valves, expansion valves

I use ester oil in R12 systems because PAG and Mineral Oil are not compatible. At least the manual says they aren't so I have never tried it any other way.

Yup I was also referring to the RV2 twin cylinder compressors. Maybe a semantics issue - IDK. Anyway, here is the relevant part of the 1970 service manual that I was referring to.