Which viscosity ester oil in RV2 compressor?

[patinated_imperial]

Last year when I changed the manifold gasket in my '66 Imperial, I made sure to tilt and drain the compressor from the old mineral oil (I THINK it was the original oil - looked like espresso). It's the original RV2.

Now I want to re-fill it with ester oil (for compatibility with R134a etc.). I have 2 unopened bottles of ester oil. One with viscosity ISO VG 32 and one with ISO VG 80. I believe I bought the latter for this compressor, but I no longer remember exactly why and can't find my notes.

Which one is best suited for the RV2?

 

[chilsam]

I run Valvoline VR60 in my Harley Shovelhead,its a VTwin n makes more heat ???...GOOD LUCK!

 

[Davea Lux]

The recommended oil for a conversion from R-12 to R-134a on an RV-2 compressor is PAG100. This is the proper viscosity and has the proper additives to prevent gelling of any mineral oil that might still be in the system. As part of any R-134a conversion, the factory o-rings should be replaced with the high density green ones and the EPR valve should be removed from the suction side of the compressor.

Dave

 

[patinated_imperial]

The recommended oil for a conversion from R-12 to R-134a on an RV-2 compressor is PAG100. This is the proper viscosity and has the proper additives to prevent gelling of any mineral oil that might still be in the system. As part of any R-134a conversion, the factory o-rings should be replaced with the high density green ones and the EPR valve should be removed from the suction side of the compressor.

Dave

Thanks Dave. I am going to take my chances with the ISO 80 ester oil then as I don't even know if the compressor makes pressure. And of course replace the O-rings and dryer.

Is it recommended to remove the EPR valve without adding a thermostat to cycle the compressor?

We charged a '69 with 1000g R134a some weeks ago and left the EPR valve alone (due to our ignorance and we were unsure if the gasket would seal without it). It cooled more than good enough for our climate (very rarely over 86 F).

 

[Davea Lux]

Thanks Dave. I am going to take my chances with the ISO 80 ester oil then as I don't even know if the compressor makes pressure. And of course replace the O-rings and dryer.

Is it recommended to remove the EPR valve without adding a thermostat to cycle the compressor?

We charged a '69 with 1000g R134a some weeks ago and left the EPR valve alone (due to our ignorance and we were unsure if the gasket would seal without it). It cooled more than good enough for our climate (very rarely over 86 F).

The system will still work with the EPR installed, R-134a is a less dense refrigerant so the system will be less efficient with that restriction in the line. You should not need anything other than the expansion valve to regulate the system with R-134a. In a perfect world, you could replace the R-12 expansion valve with one designed for R-134a, bu most systems seem to work adequately without doing that. The main purpose of the EPR valve was to keep liquid refrigerant from cycling back to the compressor and causing it to hammer. By having the EPR valve reduce the flow back to the compressor, the liquid refrigerant had time to evaporate and turn back into a gas. RA-134a being less dense is unlikely to come back to the compressor as a liquid.

Dave

 

[patinated_imperial]

The system will still work with the EPR installed, R-134a is a less dense refrigerant so the system will be less efficient with that restriction in the line. You should not need anything other than the expansion valve to regulate the system with R-134a. In a perfect world, you could replace the R-12 expansion valve with one designed for R-134a, bu most systems seem to work adequately without doing that. The main purpose of the EPR valve was to keep liquid refrigerant from cycling back to the compressor and causing it to hammer. By having the EPR valve reduce the flow back to the compressor, the liquid refrigerant had time to evaporate and turn back into a gas. RA-134a being less dense is unlikely to come back to the compressor as a liquid.

Dave

Actually a friend of mine claims my expansion valve is s newer type for R134a. He says the ones for R12 has a difference shape and that the blueish sticker said "R134a" when is was readable ?



Based on your very appreciated input, I think I will start leaving the EPR valve in place. Then if I'm (ok, my wife) not satisfied with the performance of the system, I can remove it.