I wanted an engine-driven compressor setup for on-board air, but I didn't want to sacrifice the air conditioning on my daily-driven commuter "car" to do it.  I also wanted to use a York compressor since York's have a decent displacement and have their own oil sump so do not need to have oil constantly added to the air intake to keep them lubricated (and subsequently removed as well to keep it out of your tires).  The problem was trying to fit everything in the engine bay since the York is a fairly large compressor in it own right, not to mention fitting in addition to the stock A/C pump. As they say, "Where there's a will, there's a way," so I figured out a way to do it.

Basically, I moved the stock compressor up, and put the York directly underneath it stuffed between the engine block and the frame rail.

The only thing in the way of doing this was the idle air control valve mounted under the throttle body. To get the valve out of the way, I simply unbolted it, extended the air tube going to it, pushed it back under the intake a few inches, and zip-tied it up so that it wouldn't flop around. Now there is a little bit less room to work around the oil filter, but it hasn't been a problem.

I removed the stock a/c compressor bracket and built my own from scratch. The stock bracket bolts to the engine block and timing cover with 7 bolts and I reused 5 of those. The ones I didn't use were the two small ones in the timing cover.

The big York compressor bolts to my bracket with 5 bolts. It hugs the engine block and the pulley and has a mere 3/8" clearance to the frame rail. Under load, the engine and compressor move away from the frame rail and the compressor has never made contact, so the tight clearance has not been a problem. The back side of the York is also about 3/8" away from the frame motor mount bracket. I recently noticed that there are some rub marks here, but it must only happen when backing up and so far hasn't been a problem.

My mount for the stock compressor pivots so that I can tension the drive belt similar to how the alternator belt is tensioned. This mount is not quite as sturdy as the York mount and seems to cause a minor vibration between 3200-3800 RPM. Its just a minor annoyance and I haven't bothered to try to solve the problem yet.

To figure out what length belt I needed, I just wrapped a tape measure around all three pulleys and got a measurement. I believe it was right about 40". I  picked up a generic belt at the auto parts store.

For access to the compressors, I have to remove the battery. To remove the York, I first have to remove the stock compressor and set it in the battery tray so that I can get access to the air hose connections.  The a/c hoses are long enough to allow this. In fact, I left the a/c lines connected to the stock compressor the whole time I built the bracket so that I didn't need to mess with evacuating and refilling any expensive freon. The oil check/fill plug on the York is easily accessible through the wheel well just above the frame rail.

The bracket took me a couple of days to build with lots of trial and error to get everything to fit correctly. The process was frustrating, but the end result was well worth it! I can air up one of my 35's from 15 to 35psi in about 1.5 minutes even without a tank.  With a tank, I should also be able to run air tools and then also the compressor wont need to run continuous duty.

The rest of my on-board air setup is fairly generic so I won't bother going into that. Filters, hoses, pressure switch, safety pop-off valve, quick connectors, future air tank, etc. The only thing different I added was a way to increase the idle speed a tad when the compressor kicks in. Basically what I did was duplicated the factory a/c idle-up system (a vacuum switch and an adjustable diaphragm thingy) using parts from the junkyard.

This setup should work on '85-87 22RE trucks and 4runners that don't have IFS. With IFS, the idler arm mounting bolts would interfere with the York. It may also work on '88-up vehicles, but the intake and idle air control is slightly different on those models, so I'm not sure about clearance.  The carbureted (22R) motors also have different clearance issues from my motor. No matter what vehicle you try to set this up on, it will take some time and patience!