4.3L XJ

The question on another thread was asked: How do you convert an AC compressor to air compressor?

First you need to know that there is a fundamental difference between the two types of compressors. The oil type air compressors have an oil ring, like an engine does. AC compressors are designed to run with oil dissolved in the refrigerant. In fact when you buy a new compressor it has oil in it that is forced out into the refrigerant from pressure in the crank case of the compressor. So if you run an AC compressor, you need to keep it oiled. Some have used air tool misters and others have dribbles a little oil into the intake when running. But this is a pain in the rear. You can run oil in the crank case if you vent the crank case when it runs. That way any oil is forced back into the crank case by any air escaping past the rings into it. Here is a video of my set up. Bear in mind that this has all the bells and whistles you could want. How much of it you add on is up to you.

4.3L XJ

The minimum you will need is a vent for the AC compressor, a check valve, or back flow preventer in the line, a pressure gauge, relief valve, a pressure valve and a pressure tank. It is easiest to use a manifold to hook up all this stuff on.

Robert Banks

Hi. Iv watched your video on youtube probably afound 50 times over the past year making sure i can fit tbis setup onto my offroad range rover. I have a sanden compressor and most of the components.

My question is on the oil return line. Den opened dows the oil return to the crank case at the same preasure as the air system is at or have you got a regulator for that?

When the oil is flowing back to the crank case. How do you prevent over pressuring the crank case? I might be over thinking it all.

Any help would be fantastic.


Cheers

4.3L XJ

If you use those ARB valves, they have a pressure relief in them in the off position. Also I have learned that the oil separator works better with cool air, so if you can cool it with a finned line like on a regular air compressor it is better. But the oil return is not critical if you monitor the oil in the crank case, which you should do anyway

Robert Banks

Thanks for the reply. Iv actualt been looking for you for about a year. Your the only person with a set up that i like.
My compressor is likely to be used around twice a day just to help top off the tank as i have air suspension. It would be used for offroad also. I.e tools and tyres

I dont have ARB ones although i could get. Have you a link to the correct ones?

i have a pair of pneumatic valves but they are not vented. Same with the pair of 3 way valves i have.

My system is going to use the current air tank that comes with the truck. And i have a spare manifold, pressure switch and blow out from my old range rover suspension that i know is in good condition and will survive in the engine bay.