OBA (OnBoard Air)

[KensAuto]

Here's a short thread on installing a York style compressor on a vehicle. There's a million ways to do this, and a million guys have done it in the past.
This is my version, on a '12 GMC diesel. I already have an ARB electric compressor pumping to a small tank that feeds the wireless air bag system and air horns. I'm added a second tank (2.5 gallon ?) under the rear passenger floorboard because that's the only space I have left. It's tied into the rear tank, and I left the accessories the way they were, just unplugging the electric pump.

I went with a "mini" york, a 206 model, because of limited space on a newer Dmax. They are about 2/3rds the size of a full size york (209/211):



...the previous setup. the black thing is the air bag setup:

[KensAuto]

I went with a v-belt style clutch, because I didn't want a longer serpentine belt, and if ever there's an issue, I can always just cut the belt.
The only place to mount it was on the bracket for the optional 2nd alternator (mine didn't have one). To make this work, I needed to weld a pulley to the outside of the p/s pulley. I bought a new one for about 15 bucks from GM (sounds too cheap right?) so I wouldn't have to disable the truck while this experiment took place.
the V pulley came off of an old dakota smog pump...it's the only one I could find that was solid steel...not 2 pieces stamped/welded together.

....new p/s pulley prepped for welding:


...then cut the center out of the v pulley so a puller will still fit on to the p/s pulley:

[KensAuto]

..then some majic with Ken's new tig  :) :

[KensAuto]

....then mocked it up to check alignment:



..and built this bracket from 1/4" plate:

[KensAuto]

These are the only pics I have of the adjustment bolt. It mounts to one of the a/c compressor bolts, and pivots on that end :

[stlaser]

Nice fab skills

[KensAuto]

As big D would say, Danka!

[KensAuto]

Next up was to supply filtered air to the pump. I wanted it to look somewhat factory, so decided to run an a/c style hose over to the engine air cleaner. I had to make a fitting on the lathe, that could be crimped on to the hose, and have it just push in to the rubber grommet where the air filter "popper" gauge normally resides:


...close enough:




...here's where it goes:

[KensAuto]

The right tool sure helps:



The end that hooks to the pump:



...then strapped the finished hose to the suction hose (cold side) on the a/c. In theory, this will help keep the air pump cooler on hot az days (hey, it's my fantasy!):

[KensAuto]

Next up was building the pressure hose. I've read that in several cases, that the compressor ran so hot (because it's not pumping freon/oil) that it melted normal a/c hose, so I went with hydraulic hose. The problem with that is, hydros are AN type fittings which are 37* flares, and a/c fittings like the one on the pump, are SAE 45*. I've checked it for leaks multiple times and it isn't leaking (so far) so we keep going.

Here it comes off the pump and hooks to a check valve. i moved it a couple feet from the pump to keep heat from destroying it (I hope). it drops down from there and is strapped to the a/c drier, hopefully condensing some of the water vapor before hitting the tank.


the check valve:


...you can see it in the top left corner of this pic:

[KensAuto]

In researching the use of a york style pump, I've read, and have some experience, with them pumping out all of the oil in their sumps over a fairly short time frame. They are designed to allow oil past the rings and into the a/c flow to keep cool and to keep from building up oil in one area of an a/c system. One fix for this is to plug an oil passage behind the front seal, that directs oil into the suction port of the pump. Some guys report that this helps, while others say it didn't do anything to cut down on the oil loss. I plugged it anyways, just for giggles. No pics of that procedure.
To catch this rogue oil (and moisture) I plumbed an air filter in right at the tank.

..speaking of tanks, here is the tank my buddy gave me. The mounts were cut off, but the color matched my truck. A bonus!
First I welding in a drain bung, that will house the blow off valve/drain:


..then welding on a larger inlet bung. It was 1/4, now it's 3/8 NPT:

[KensAuto]

Then cut off the bracket that used to have mounting tabs of some sort:



..notice i painted underneath it, before welding on the new mount, which is just some angle iron:

[KensAuto]

Here it is ready for install:



..mounted to frame with the air filter on:



...and quick connect and gauge on other end:

[KensAuto]

I used the pressure switch off of the electric compressor to engage the new pump, and quickly realized that it was set way to low for my taste. It came on at 80, and off at 100. So, I ordered one that came on at 120, and off at 150:

...and then the leaks started sprouting, most of which was the solenoid that allowed air from the rear tank into the air bag module....it was only rated at 100 psi.



...the new one showed up and went in pronto. It's rated at 175psi (and it's shinier):

[KensAuto]

Now all is good. It works without me even knowing it's there (unlike that noisy *** arb unit). The pump is a little small for full on impact wrench use, but it's perfect for what I wanted. My main gripe with the electric one was noise, and durability. Every time the ignition is cycled, the air bag system purges to disperse any moisture, and when it would do that, the electric pump would cycle.

[Wilbur]

That looks really clean....nice job! I have wondered something about onboard air- I get the need for a system like this for folks running airbags or an air locker and need air "all the time". But my question is for someone who needs it solely for airing tires up/down or to run an impact or air jack wouldn't a smaller elec. unit be almost as good or as good? And potentially a lot cheaper? (Obviously if space is a concern then that might not be a decent solution....but just curious)

[KensAuto]

Thanks!

You would have a hard time running any air tool from an electric. This compressor puts out about 2 cfms at idle, with the small clutch. If i need more air, I can just raise the rpms.  (store bought) Electric one won't do that, unless you have a bunch of time to wait between lug nuts. That being said, the system I had worked fine for what it was for, just wasn't good enough for Me.. lol

[rpar86]

I love this idea! I've looked at doing this on my truck someday. I don't have a need for dual CP3's or a second alt, so this seems like the perfect mod to take up that empty space in the engine bay. Very clean Ken!

[stlaser]

The electric are ok I had one on my eb for airing up tires (took forever). If I did it again I would go Kens route.

[TexasRedNeck]

well if you had a dually..... ( I have a compressor in each wheel well)

I have twin 440Cs feeding a 5 gallon tank at 175psi.  I haven't found a tool it won't run yet.  It runs my 1/2 inch impact to change tires on the 5er and the dually and run the air over hydraulic bottle jack....

I may try the York on the LB7 to see how it's done.

[KensAuto]

Sorry, I didn't take into account people like Mr Overkill there^^^^ that have twin jet propulsed high output 440s pushing a buckseventyfive. SMH

....and, mr tex, you were curious before, so I did all of this for you!



:)

[TexasRedNeck]

Awesome Ken. Much appreciated. Come to texas and do the install on my LB7....I'll feed ya


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[Flyin6]

Nice work Kenneth!

That looks to be well thought out and engineered...Kuddos!

[KensAuto]

Thank you sir!

[cj7ox]

Nice work, and write up Ken!


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[JR]

Can't believe I just found this, great job Ken.

I have to look and see which pump I have outside, but I think it is a full size off an older dodge truck.