Re: Using My A/C Comp. for Air?
I took the below few paragraphs from a write up I did a while ago. This is also on a 1980 CJ7/258. I've cut to the part that I think you are asking about. So at the end I offered a guess of dollars spent. That included all parts from a wrecking yard so since you aleady have the engine stuff you'll save over half I suppose. Any specific questions you have repost and we'll connect via email if necessary. John
The top of the compressor has two fittings. On the inlet side I put a small air filter, the type that goes on a oil breather. Got mine at a VW parts store.
On the other fitting (the outlet side) I put the air line. In this line I added a couple of features that have turned out to work great, First I went to a place that rebuilds air compressors and bought a pressure relief valve (a pop-off valve?) and a pressure control switch. The pressure control switch turns the compressor on and off at whatever air pressures you set, I have mine go on at 90 lbs and off at 125. That means that when the compressor is running and air pressure in the system drops to 90 lbs it goes on and when the compressor reaches 125 lbs in the air tank the compressor shuts off. The pop-off valve is an extra safety measure and mine is set for 125 lbs, that way the entire system canít go over 125.
I then ran the air line to a storage tank. The tank I use is a 10lb fire extinguisher bottle. How I did this is pretty simple, I took the fire extinguisher to a good auto parts store and got a 3 way T fitting that screws into the threaded top of the fire extinguisher, the second part of the T gets the line from the compressor, and the third side of the T is my air line that runs up under the hood and mounts just under the battery tray. I use a female quick disconnect fitting on that line. That is where I plug in my air hose to air tires, air tools etc. I mounted the fire extinguisher tank to the underside of the floorboard between the frame and the drive shaft on the passenger side. Made some straps to hold the tank up against the floorboard. The rear of the tank is about even with the front of the rear spring and the front of the tank is even with the rear of the skid plate. It seems out of the way here. Some folks on this Jeep page have cautioned against using a fire extinguisher as they say the pressure is too great for it. However I never drive around with air pressure in the tank, just use it when airing tires etc. I donít think I would use this for ARB set up as it would mean having air pressure in the tank at all times.
So, getting back to the outlet side of the compressor, hereís the sequence of whatís in line: from the compressor outlet I run a short piece of air hose to 4 way brass fitting which is mounted on the fender well. On the second side of the 4 way fitting is the pop-off valve set to 125lbs. On the third side of the fitting is the pressure control switch, and the air hose to the tank is on the 4th side of the fitting.
Next, I put a toggle switch in the electric line that goes to the compressor, I took the wire from the compressor, ran it to the switch, then to a fuse junction box - so that when I want air all I have to do is raise the hood and flip the switch. Iíve got to raise the hood anyway to plug in my air hose so itís easy to flip the electric switch to engage the clutch in the compressor. The system fills the air tank in about a minute.
I bought an air drill from Harbor Freight, have an air chuck for tires, and an air nozzle to blow off dirt or dust. I keep the air nozzle plugged into the air line under the hood to help keep dirt out of the quick disconnect. Mine will run power tools though I donít carry an air impact wrench.
This pretty well sums up what I have done. The Jeep page has lotís of good ideas about this set-up. Most, if not all, agree that it doesnít matter if the compressor is upright or on itís side. Most believe that oil should be added. There have been many discussions about tanks, some use bumpers, other style tanks and so forth. I have seen discussion of the various York compressors, one page talked about long stroke vs short stroke compressors or some such. I donít know what I have except it came of a early 80s Gremlin or something like that.
How much did it cost? I didnít keep track and this was a long time ago. Probably spent in the area of $150 to $200. Maybe one of those Ready-aire or other systems would be ok. A friend has one, he paid about $150 for, it really doesnít work nearly as fast but if you have the time it would sure be easier.
Many posts have stressed the need to add oil to the compressor. I did at first but for some reason it pumped it out. That was 8 or more years ago. Since the first couple of ounces I added, I have never put in more oil. Still running, maybe I've just been lucky.