OBA

My goal was/is to install a clean looking, fully functional (ie air tool capable) OBA set-up as cheap as possible. Judge for yourself if you think I accomplished my goals. There are numerous sites with write ups on OBA and usually they reference Kilby's On Board Air Site. While there is some good info, I found better info searching all of the write-ups I've found. Due to the dynamic nature of the web, a lot of links that people list in their write-ups (even Kilby) come and go with the wind. My suggestion is to copy/print/save every bit of info you run across. I printed out everything that I though would help me and put it into a 3 ring binder that is now full of articles and info just on OBA.

After long research, most write-ups will tell you how and where to look for a good, used York 210. York 208's and 209's are smaller but WILL work just as well for airring up tires and WILL fit Kilby's brackets. 210's are most common though. Yorks also have left and right air intakes. All I could find was left intake and had I found a right intake, I could have installed it on it's side. This wouldn't have made any difference performance wise, but would have been a cleaner install. Once you've found a donor York, clean it up. I was lucky as I found a local place that works on semi's that pitches Yorks and gave me an endless supply (reason enough to wheel with yzer!)!!

Here are 2 of my Yorks, pre-clean up...

The one on the left is a "flange" top and the one on the right is a "rotolock" or "tube-O" top. Flange tops are the most desirable because installation is quite easy with a set of Kilby's flange fittings. Kilby also sells rotolock/tube-o fittings and there are ways to Home Depot your way, but I stuck with the flange and will reserve that knowledge for another article. BTW, if you find a bad flange top compressor, grab it as you can switch tops with a good rotolock/tube-o compressor.

Here are the two types of fittings From Kilby's site...

The next piece in the puzzle is what type of belt/pulley system you have and to use. Older Jeeps use the V-belt while newer Jeeps use a Serpentine belt (multiple grooves in one belt). Additionally, some set-ups allow you to use a V-belt with a Serpentine set-up. What type you can use will determine the cost. Most Yorks come from the junk yard with a V-belt pulley already attached. Serpentine pulleys are extremely rare in the junk yard with only early '80's Mustangs with dealer installed air or '70's semi trucks using them. Serpentine pulleys are found on ebay, Kilby's site, or at semi truck parts places. I got mine at a semi truck parts store for $82, which was the cheapest I could find a new one for.

Here is a picture with the new serpentine pulley on the York and the old v-belt pulley in the background...

Once you've cleaned up your York, there is a way to cut oil consumption by 90% but after doing exactly as was described, I still get too much oil in my lines. So it isn't worth the effort in my opinion. After reading the York Compressor Service Manual, I drained and refilled the compressor with 30 weight oil throught the side fill hole. I used a cap from a water bottle and the side measurement indicators on the side of the oil bottle to approximate the needed oil. I would suggest using only half of what the manual says to. You can always add more later if needed.

Here is the oil filler hole/bolt on the side of the compressor...

Once the compressor is ready to go, it is time to install the bracket. Mounting brackets are just flat metal in most cases and many people have fabricated their own. I did not have the capability to do this and feel fine with buying a bracket that somebody engineered to work with my engine. Something about not having the bracket just right with a belt/pulley system running at a million rpm scares me. Anyway, I got my bracket for cheap off of the Quadratec BB from somebody who got it from Kilby and didn't use it. Since my install was going on a 2.5L with out air conditioning, I had the perfect spot in my engine compartment to install it. I learned later though that it would have been a bit easier and cheaper if I actually had factory air and just converted the factory compressor. This is easy to do, you just have to add an oil sepparator and loop it so it feeds the oil back into the compressor. Here is the Kilby bracket installed on top of the factory air bracket...

After installing the bracket, it is time to install the York. In the next photo, you can see I have the Akimoto Funnel Ram I got from Quadratec. What you can't see is the Poweraid Throttle Body Spacer I also got from Quadratec. Reguardless of installing a York I highly reccommend a funnel ram intake and a throttle body spacer, especially on a 2.5! What is important here is that the funnel ram removes all of the factory intake stuff, which makes the install easier. The trottle body spacer moves the intake up an inch which, for me, created more clearance for the York...

Once the York is installed, you now have some serious thinking to do as to what you want out of your set-up and how to install what you want. You'll need to diagram the lay-out to figure what connectors, accessories, and what-not to purchase. This is where checking out other set-ups online and in person will help. I got a lot of good ideas off the net and definately did NOT want my set-up to look like something from a WWII era submarine. Some people use steel plumbing fittings which will work and are cheap, but look like crap in my opinion. Also, I was able to scrounge some freebies from others who've done the OBA thing because everyone who has, buys more than they need. Even I have a bucket full of left over parts. This is where careful planning and a good diagram will save you time and money. In addition, whether or not you want to run air tools and have a storeage tank will determine what you need. At this point, you could install an oil separator (coalescing filter), a quick release, and a power switch and you have a great compressor that will air up your tires. Or you could go the route I did and add a tank and the neccessary stuff to go with it and have a mobil Craftsman quality air compressor that would run air tools as well.

After I decided to go the full install route (tank and all), I searched for a tank. I loathed the idea of paying $60 to $80 for an airtank and researched used small air compressors, portable airtanks, etc. I found that Firestone makes tanks for air suspensions (popular with the lowrider crowd) for about half of what Kilby & Viair want. An example is here with #9148 running $36.72. It holds 3 gallons, has 3 1/4" ports, and measures 7"x20".
Here is a picture...

The one I got was a 3 gallon semi truck air brake tank some guy had a dozen of on ebay. I got it for $5 plus shipping. Once I got it, I had a couple of 3/8" straps welded on as mounting points and mounted it on the drivers side in the space between the frame and the drive shaft behind the transfer case. Here is my tank with the straps welded on...

And here it is in place...

I knew from my diagram that I wanted a quick disconnect both in the front and the rear of my Jeep to allow me to run air tools on the trail to the vehicle in front of me and behind me without having to be right next to the other vehicle (Colorado Mountain trails are only ONE vehicle wide in most places) and I also wanted everything under the hood except the on/off switch and the disconnects. That way I didn't have to pop the hood each time to use my OBA. I got a "weather proof" switch from Checker and installed it in the front firewall. Once I figure out where and how to mount a series of switches inside the cab, I'll probably move it to that panel. I knew that I needed an oil/water separator and got one from Home Depot for $20. After using my OBA for a while, I will say that the Home Depot one sucks at keeping oil out of the line and reccommend you pop the $75 for the Coilhose unit on Kilbys site. But in contrast, my friend has gone through two Coilhose units that blew the seal around the glass because they couldn't hold up to the pressure while my el-cheapo unit from Home Depot has held up just fine. I have not been able to find one cheaper. Anyway, here is my oil separator installed on the radiator support rod...

I heard first hand of the first few feet of outtake air being so hot that it blows the airline off of the compressor or blows a hole in the line after several minutes of use. Some people have used toilet plumbing lines with steel braid to fix that. I found a steel braided gas line kit at Checker for $20 and used it. Steel braided line is a pain to cut right so if you don't have the tools, use it the length it comes. Using the steel braided line eliminates the heat problem and looks nice. If money wasn't an issue, I would have bought it in bulk from a racers supply and done the whole set-up with it. Here is an overall pic of the air lines to this point...

In keeping with my "el cheapo" theme, I simply put a "T" fitting onto my oil breather line and ran some hose to the air intake side of my compressor. I figured that air was already filtered and that I didn't need an intake filter. Good in theory. I've since learned that using the breather line with such a small diameter hose might allow the York to actually suck oil out of the engine. It has THAT strong of suction! My advise: if you're going to go through the air filter is to use a 3/4" diameter or larger hose or spring for a filter. The cheapest I've heard of was using one for a lawn mower from Home Depot at about $4. Here is how I originally set up my air intake...

Coming off of the oil separator I needed a manifold to split off the front/back lines and to house the needed accessories. I didn't want to shell out $35 for a block of aluminum and after a long search, I found one at a tool store made for an air compressor that had two 3/8" and five 1/4" ports for $15. Perfect. I knew I needed a one way valve since I was using an air tank and found a nice one at a plumbing supply place for $4 that, again, didn't look like something off an old navy vessel. I also needed a pressure switch (to shut the compressor off at a certain psi), a blow valve (in case the psi got too high - don't want a bomb under my Jeep), a pressure guage (to tell me what psi I'm at and where it comes on/off). I laid out my set-up to make sure it all fit on my manifold and this is what I came up with...

And here is what it looks like installed...

I picked that location because I wanted it out of the way and easily accessable. Notice that the pressure guage faces out so I can easily see the pressure. I bolted a u-bolt over the manifold and through the fenderwell to hold the manifold securely in place. After finishing the install, I painted the gray cover to the pressure switch black to look less noticible under the hood. Kilby sells a smaller switch, but since I got mine in a deal I stuck with it. I used a hole in the fenderwell to run the front line and ran the rear line down to the frame along the brake lines to the air tank. And from the back of the tank to the rear bumper. Here is the line running down through the engine compartment under the chassy back to the tank...

And here is how I ran the line under the fenderwell...

I ran it to the front grill and then through a hole in the bottom of the grill to a quick release...

Here's what the rear chuck looks like on my AtoZ Fabrications rear bumper...

You'll notice my cool covers for the quick releases. I stole that idea from a firetruck. At the end of the nuts & bolts isle at Home Depot you'll find packages with all sorts of rubber feet for chairs and such. I took my quick releases (also from HD) and test fit the rubber feet. When I found the ones I liked, I found a pack of washers that fit inside the feet. I also found some cotter pins and got 1 foot of chain in the same isle. After putting the washer inside the rubber foot, I ran the cotter pin throught the chain at on end and the pushed the pin through a hole I drilled through the foot. I then bent the ends of the pin to secure it. The other end I used a self tapping screw to secure to the Jeep. Now, my quick releases stay dirt free and if I lose one, I have spares. Here is a pic of what I used...

I wired the pressure switch to the on/off switch in the front grill, and then the on/off switch to the clutch on my seprantine pulley. I ran the other wire from the pressure switch to the positive power wire that connects to the positive power supply that is on the relay/fuse box under the hood. You don't need a negative ground wire as the compressor grounds itself to the engine. So, basically the wiring is one giant loop. Here is the front with the on/off switch in the lower right of the grill...

All that was left was the fan belt. This was a chore as nobody (not even Kilby) knows what belt length you need for the serpantine set-up in a 2.5l w/out air conditioning. After three trips to Checker, I finally took a cloth measuring tape (made for sewing) and figured that I needed 17" of additional belt. I knew from the manual that the factory belt was a 060790 and after a quick lesson in "beltology" at the Napa store, I learned that the 06 was 6-ribs, and the 0790 was 79 inches in length. Adding the 17" to the 79" gave me 96", therefore I needed a 060960 belt. Walla, perfect fit. I threw the old belt under the seat as a spare since I probably wouldn't need my OBA to get me home if my belt ever broke.

So, how does it work? Awesome! I hop out of the Jeep with the airhose in hand and flip the switch on the front and within a minute I have 120 psi in my 3 gallon tank. Here is a pic at 115 psi...

It takes about a minute and a half per each 33x12.5 tire to go from 8 psi to 30 psi. It could go quicker if I locked down the hand throttle to keep the rpm's at 2000-2500. I can run air tools on the trails non-stop and I've even ran a nail gun at a construction sight. Hopefully I'll get the oil problem worked out and will be able to run a spray gun and use my own Jeep to spray in a bedliner. How cool would that be? You might have noticed I used two different types of air line. I bought the blue 300 psi rated air hose at a True Value Hardware store for .50 a foot which uses the press on type fittings with a hose clamp to ensure they stay on. The black hose is a 3/8th's inch brake line hose from the semi truck parts store which utilizes the compression ferule type fittings. I like the brake line better as it is smaller and easier to run/hide, but the air hose line is more flexible. I used teflon tape at ALL of my connections and have yet to have a leak. On the bottom of the tank I have a petcock and drain out the air whan not in use to prevent moisture build-up. I have not added up what all I spent on this set-up but would venture to say that with all of the trial and error stuff, even though I got a lot of stuff for half of what it would have cost me through Kilby (even getting some stuff free), it still cost me a lot less than $200 total. I plan on writing a step by step outline complete with part numbers, prices, and pics of every step someday. Hopefully this will help those who want to embark on such a task.

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On-Board Air using a York 210 Compressor