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Cons_Table 03-10-2010 02:30 PM

Turning XJ AC into OBA?
My buddy got an extra engine when he bought his XJ...and the engine has an AC motor on it that he would be willing to give me to set up some OBA. I have heard of people doing this with a york compressor, but was curious if anyone has done it with an XJ compressor or has a good link for building this? Thanks guys! :wavey:

Jerry Bransford 03-10-2010 02:52 PM

That particular compressor is a rotary style which does not have an internal oil sump like the York does. Rotary compressors receive all of their lubrication from a bit of oil added to the refrigerant. Once the refrigerant is gone, you have to come up with some way to provide lubrication for it when it is in use. Some just squirt a lube into the intake before use but to me, I'd rather just spend the $30-35 for a used York F210 compressor that is easily found in most junkyards. That's where I found mine 9-10 years ago & it worked great in my OBA system with never a problem.

rrich 03-10-2010 03:37 PM

Well - Almost. Either York is a good choice.

The Sanden and Mitsubishi compressors used on the Cherokees and Wranglers - and Dodge trucks, and --- actually do have an oil sump. On the side of the compressor, about the middle, there's a big slotted screw. That fills the sump around the crank and bottom of the pistons. Here's a link about it.

But every once in awhile a little oil should be shot into the air inlet too. That lubricates the top end - the upper piston and the reed wobble plate. Use an oil separator on the output to keep it out of your tires. DO NOT MAKE THE SEPARATOR DUMP BACK INTO THE COMPRESSOR. Most of what it separates is water!

The Sandens don't have quite the CFM output as the Yorks, but they will air a 35 from 12 lbs to 28 in a little over a minute. 8 CFM compared to 10.

I oil mine about every 12 tires or so. About 1/4 oz of oil sucked in the intake.

Make sure it gets clean air - a good source is tee into the air cleaner's PVC line.
Hook in a pressure shut off valve, a gauge, and a switch for the clutch. A one way check valve also helps.
(Parts are available from Grainger.)

The advantage is they are smaller, and if converting from AC to OBA it's already mounted and you have the tubes to attach to - easy to set up.

Parts are readily available and they are easy to rebuild.

Pics available.

Cons_Table 03-10-2010 04:11 PM

I know that the compressor I would be using uses the refrigerant as lube, I was just curious if there was another way to lubricate this type of compressor in a fairly inexpensive way. If not I may go ahead and look into the york OBA

rrich 03-10-2010 05:13 PM

The refrigerant is not lube. It has oil added to it that circulates in the system.
That's why you add a little every so often to the intake. It doesn't need much, a few drops. I usually do it when I change oil.

Look on the side of your compressor - you'll see the fill plug for the crankcase.
Look on the site I posted, you'll see the lube in the crankcase and how much to put in.

On either type compressor you should have the separator to keep the oil out of your tires.

I've used mine for about 4 years, worst problem was I blew a hose because I used a cheap hose.

Mitsubishi and Sanden - very similar - Jeep used them both.

Avoid the big round but short GM's - I hear they give lots of trouble.

Cons_Table 03-10-2010 05:22 PM

hey rrich, that link didnt work in your previous post. do you have another?

Jerry Bransford 03-10-2010 07:17 PM

That link only says they have a dipstick & some sort of small oil capacity which isn't enough to run them with.

Cons_Table 03-10-2010 07:28 PM

Thanks for the input guys, I may look into my junkyards to see if i can find a decently priced york (some of the places around here are kind of a ripoff) what are the best vehicles to look in for the yorks?

Jerry Bransford 03-10-2010 07:37 PM

Older Fords & Volvos for two. When I bought mine, I expected to have to go through the wrecking yard to find my York. Nope, they had about a dozen Yorks already pulled & sitting up on their shelves.

Test them before buying one if you have more than one to select from. Connect +12 volts up to the compressor's solenoid wire (there is only one wire) & ground the compressor case to the - post of the battery. You'll hear the solenoid clunk as it engages.

Place a finger over the ports one at a time while you spin the pulley with your other hand & pick the one that has the best suction & output pressure. This was pretty easy, some yorks had noticeably better suction & output than others. My junkyard was happy to get a battery & wire for me so I could pick out the best York.

Cons_Table 03-10-2010 07:46 PM

Thanks Jerry! I figure it doesnt hurt to take a look around at my options, before spending the money on making the XJ compressor fit my wants and needs :wavey:

rrich 03-10-2010 08:24 PM

The link didn't work for me just now either, but I found it again.

That link says depending on which compressor is used, it takes between 3 to 5 oz of oil.

According to the pictures I must have the SD series. My Jeep isn't here at the moment - wife has it today - so I can't look at the serial plate to see which one I used on mine.

It must be enough oil - it's lasted over 4 years and filled lots of tires, not just mine but others too. Every time I've checked the crankcase oil it's never been down or low, so apparently it doesn't use any from there. The oil in the top end gets blown out a little at a time. It's only lubricating the reed flapper valve and helps seal the pistons (no rings on them, just a tight fit in the bore.)

I'll find another link too. I downloaded complete rebuild instructions once from the net, I'll try to find it.

I get them from shops and the local dealer that they took off - for free. They replace them when a seal leaks a slow leak, losing refrigerant. But for OBA a slow leak doesn't matter.

I have had a couple that did not pump - I took off the endplate (cylinder head) to access the reed flapper valve. Every time it was a piece of grit trapped under the reed. After cleaning and reassembling they worked fine.

They come with either V belts or Serp belts. You could run a longer Serp on the engine, or, I make a double pulley. I get another alternator Serp pulley, use a lathe to hog out the center of one of them, then weld that one onto the one on the alternator - carefully so as not to create runout. That way you can access the inner pulley to tighten it by reaching through the center.

Then I use a short belt to drive it.

I've installed maybe 5 or 6 so far, always the same way. They've all been in service for quite a while now, no problems.

I went with the Sanden/Mitshbishi because of 3 reasons, small- fits nicely in the room I had, easy to mount, and I had one left over from an AC job.

Here's a link to the repair manual. SD compressorservice manual.pdf
pg 13 shows how to make your own dipsick.
pg 18 shows the filler hole.


I did a search on Yahoo “Sanden compressor repair manual.” There's lots more info there.

I've been happy with it. And IF you are eliminating your AC - it's a real easy way to go since you already have one mounted and turning.

Adding it to something that already has AC that's to be kept it needs to have a mount built for it. There's 4 long bolts that go through the case on most of them - good place to hook to the new mounts you make.

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