OBA-Will my setup work?

Snarky

NAXJA Forum User
Hello, I’ve been reading the forums about OBA and have decided to convert my air conditioning in to an air pump. I think I have the overall setup down, except for the wiring. I also used cherokee america, they have a great diagram of the OBA setup for converting the AC to air compressor. Their way of doing it looks like a solid reliable way to make an OBA, but it seems like an over kill for me.

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My way:

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As you can see, I want to keep it pretty simple. Now, I was planning on doing the oiler and air filter / separator. But then I talked to my auto shop teacher about it and it turns out he has done this to a few of his Jeeps also. When he did his, he left out the oiler, and just dropped a little bit of oil into the intake before he used it. He said that the other way probably works great but is unnecessary, unless you plan on using it all the time. Which I know I not going to use it all the time, maybe once or twice every couple of months.

My main question is, can I just turn on my AC to start the pump? Or am I missing something here? The way I view this is, when the air conditioning is off, the clutch on the compressor is disengaged so it doesn’t pump. Then, when you want start the compressor, you simply turn on the AC and it will engage the clutch, which then it starts pumping air. So do I need to wire anything up? This seems a bit too simple.
 
The A/C compressor on your 93 runs when you switch on the A/C, but it also runs when you switch on the defroster. Apart from the option of just disconnecting that circuit, do you really want to risk seizing up your compressor to save the marginal expense and trouble of installing an oiler to keep it happy? Saving yourself a penny's worth of trouble in the driveway will eventually result in your facing a pound's worth of trouble at the end of the trail with aired-down tires and a seized compressor. Do it right the first time.
 
Wire it as per the CA instructions...include a relay on the clutch circuit. Include a oil/water seperater on the output, for the input you need a way to add oil, either a oiler or manually (dont forget). Check out Kilby for more info. I have just done this with mine, as others have, I am waiting on results....to early for me to give much advice.

Rev
 
Check out Harbor Freight for a Oiler/regulator/filter combo! Last I saw in thier catalog (online and in store might be diffrent) they had a nice one at 70% off, i think the cost was less then $15!! Get one of those and take the 3 piece apart and install them in your system where you need them!! Its a damn good deal, and works well!!

I know the filter isn't designed to filter oil, but for what little oil runs through the system it works well!!

Thats my advise if your looking for cheap and effective(aren't we all?) I'm almost finished with my install, still need a pressure switch, but its done for the most part!

Here is the Oiler/Regulator/Filter combo i got from HF:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42035
The thing I dont like about it, is that the Regulator and Filter are one unit, i would like to have them seperate so I can put the regulator farther back in the system.

Here is the one from HF that was on sale in their most recent catalog(looks like its cheap on the website too, it used to be $40):
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=45009
This is the one I would get if I was just starting my OBA project, it lets you put each piece where you want it!!
 
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Yes, you do need and oiler so get a good one. Mine is Campbell Hausfield. I just used one of those filter stones on the intake side of it for a filter. As far as the filter/seperator you should have one of these too. But, be aware the air being compressed and coming from the AC unit will be extremely hot due to it being compressed and will melt anything plastic you put inline within a short distance so many people suggest getting an all metal unit. I ran a pressure switch off of a "t" fitting after the check valve and also used a guage I mounted inside with a switch. The kit I bought comes from Viair and comes with Guage/switch in a panel, your choice of on/off pressure switch/relay unit(I got the 85/110 psi) and small hose and wire to hook up the kit. I ran all 1/4"npt fittings and ran 3/8" goodyear oil resistant air hose(harbor freight for about $12) across the firewall and down the fuel lines to the rear where I drilled a hole in the floor and hard mounted a 90deg fitting with hose from that to a 5 gallon airtank(also harbor freight $15) in the rear cargo area. On the tank I mounted (2) "t" fittings. One with the pressure release valve and the other with a quick disco fitting. This entire setup was done for around $120 and it fills the 5 gal tank in about 30 seconds to 110psi.
 
I seperator will pull the oil out of the air, right? I didn't even think about that. I've got mine set up right now without one, because I was thinking I needed to do something like Kilby's oil recycling kit. Maybe I'll go pick one up if it will work.
 
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