OBA-On Board Air

[Bill usn-1]

OK some may remember I started this project while I was doing my complete overhaul of the scout. Well project creap kept me for finishing it.
Here is the link to the beginning showing the dual sanden AC bracket.
dual AC bracket


Here's the original compressor. Notice the valves on top.


So, that is where I left off.
Well a couple other items were needed.
First is a pressure switch and a gauge.
I picked up a couple cheap ones from Lowes or something like that. Most hardware stores and even harbor frieght and Northern tool normally carry them.
They only had a 30-50psi switch so I had to make it do. I had to do all my shopping before I left the states!


I also picked up an assortment of brass fittings that I thought I would need and I spent a little time at the local parts store getting the right size belts to put the system together.

First you need to beable to hook to the compessor. I have seen a lot of different ways to do this but I think I came up with a very simple solution!
The large valve from the old compressors fit tight on the new sandens, and to top it off. the hole in the large valve is the perfect size for a 1/4 pipe tap which is exactly what you need for OBA connections!!


Now if you want to take the cheap way out and just connect everything with your $5 HF air hose than here's what you do. Just screw a 3/8 hose barb in and hook up your hose!!


But I have seen my fair share of them things letting go out on the trail just when you need them.
They don't like the heat and oil under the hood!
So I decided to hard line as much as possible.
My first thought was to use 3/8 copper tubing. But I forgot to pack it with my shipment!!
So I decided to just go with brass.
Here it is mocked up.



Once I got it where I wanted it using the limited supply of fittings I had, I pulled it back off and used teflon tape on all the connections.



With it remounted I decided to try it out.



A little adjusting on the tension spring in the switch and I was up to 80psi!

But pressure does you no good without volume, so I drilled and tapped my new front bumper to use as a tank, that's what it was designed for!!!


And since I don't have a reoiler...these compressors do put out some of the oil in the air...I didn't want to use a "T" so I drilled and tapped a second hole for the out let. That way any oil or water will stay in the bumper and not go in the tires or tools. (yes I will add a drain in the bumper)



And after a little more tweaking...

105psi.

Oh...did I mention I tied the clutch wire to the EFI computer so it will raise the idle to 1500 RPM when the clutch engages. And the 12V going to the pressure switch will be on a manual switch to be able to turn it off.
At 1500 rpm the compressor will maintain 30psi constant flow with no tank.
The intake filter I found locally at a hardware store here in Sicily. It has 3/8 pipe threads so it's just right for a short piece of heater hose!!

So all I need is a rear bumper and that will double my tank storage!!
Should be fine for even short use of air tools during trail repairs...on Heeps!!!

Did you notice my 350amp anderson disconnects for the winch?
Now I can pull heeps from either end!!!

Other build ups.
Rear Disc Jeep D300 OBA OBW Interior PS pump reseal Hydro boost Mirrors Headliner
SOA Bushing replacement Roll cage And of course..FI

[Sean Wetgen]

Ok, I'm not exactly sure what a guy needs OBA for, but looks like a sound system. One thing I can think of, if you didn't have oil in the lines, a guy could install a truck air dryer. That way you wouldn't get as much moisture in your tank. Some food for thought.

I see that nice pearl red engine in the pictures. Sweet.

Whats wrong with getting a real truck air compressor? Won't fit correctly, or some other reason? I'm not blasting your ideas, I do like the 12v clutch control. But with a regular compressor, you really won't get oil in the lines. Thing is, you'd have to run a couple of water hoses to it to keep the housing cool. It would probably cost more with the real compressor, and control wouldn't be an option. But still whats the reason of OBA? I am still learning what off-roaders do. For me, off-roading consists of mud, 4wd, and a case of beer. : beer : : thumbsup : histeric Keep up the good work, and pictures. Some people learn better when they see it first hand(aka me ) Take care everyone!

[Eagle-Mark]

Main reason people want it is to air up tires, as you let the air down to off road. Sometimes as little as 6 - 8 pounds. Air up to go home. I like air to run air tools. Anyone who breaks someting just loves it when you pull up with 1/2 impact gun to take of wheels, springs etc... also nice to have air to blow things clean and dry like a disrtibutor cab... die grinder and a cut off wheel... I carry an air chisel too!

[Bill usn-1]

Yep all that and,
I don't have an air compressor over here or a welder. It's like being out on the trail!!

The main point is to be self sufficient.
No one likes to wheel with the guy that has stuff falling off his truck when he gets to the trail. or has a flat and doesn't even carry a jack!!

These things are mechanical and will break. If you go out on the trail and start pushing them harder than you need to be prepared to fix them.


If you are just starting out than go to HF or Northern tool and buy a cheap set of basic tools to carry with you on the trail.
That way if something happens to them you will be mad but not out a lot of money.

Everyone starts somewhere.

As for what compressor to run....size matters. I wanted the smallest most efficient I could get. The sandens are very good replacements for the AC compressor and seem to do pretty good for air.
The factory york makes a very good air compressor but takes up more room.
I needed duals because I am running AC and air.

There are some nice electric compressors that you can mount under the body but they are out of my price range...I'm all about cheap. My time is free "for my stuff"

[Sean Wetgen]

Yeah I guess I never thought of it that way. I thought maybe of air ride/air shocks, something like that. See, I'm not used to the concept of major competition off-roading, or sunday off-roading.

[Binderman]

Sweet write-up!!

Glad to see your taking time away from your sight seeing to finish up the scout

At first I was worried about how you were gonna route the belt/s. I thought if ya ran just over both pulleys/clutches with one belt that there wouldnt be enough belt to pulley contact to turn the A/C compressor.

I see ya ran two belts.

I was afraid you might end up like that poor group of fella's on Monster Garage that tried to belt drive two hydro pumps off of one belt. Even I know better than that. Needless to say they didnt win any tools : histeric

Now a question for everone. Did IH ever use a steel compressor brkt on the SV engines or were there just the cast iron ones? I want to add OBA to my 800, but want to go a different route.

Good job Bill!! Found any heeps over there yet to use the air stuff on?

[Bill usn-1]

No one will play yet.
I even put an ad in the base paper looking for guys to wheel with.
I got 2 respnoses.
1 from a guy with a 4 wheeler and 1 from a guy with a jeep that has never been off road with it yet!!!

So I'm going to try and get in touch with some locals.
I'm hearing their off roading is flying down dirt roads like prerunners!!!

We'll see.

[mporter52]

Hi Bill,

What was your source for the compressors?

Thanks

Mike

[Bill usn-1]

EBay is my friend!! : thumbsup

If it not for EBay, I not be wheelin today!!

[mporter52]

Does it matter what model compressor, and/or what car its for?

Did you do a write up on your on board welder? I searched but couldnt find it.

Thanks

Mike

[Bill usn-1]

The OBW is next along with an alternator upgrade kit.
I'm still waiting for the rest of my parts to arrive. Takes a little longer to get stuff over here!!!

I did a lot of different searches for compressors on Ebay.
try AC + sanden, jeep, dual pulley, double groove. or just search through the compressor only section under automotive parts and accy.

Start in this section the narrow it down with the search.
AC

Look at at 505, 508, 510, SD5........Pay attention to the hose or valve attaching ports. They make a lot of different ones.

[mporter52]

Bill,

Ive been looking over this write up and cant figure out how you routed the belts. I see that its 2 belts, does the 2nd belt just go over the 2 compressors? and the 1st belt is on the first compressor and the water pump/crank?

Do you have any more pictures of the bracket you made?

Oh, and is there any reason you didnt add a air/water separater?

Thanks

Mike

[Bill usn-1]

I run 1 belt to the outside pulley on the water pump.
Then I run a short belt from 1 AC unit to the other.

The alt still has 2 belts going to it.

Right now my OBW is on the inner pulley on the water pump.
It was from a scout with a smog pump.
More on that later.

I may redo the holes in the bracket and put the AC on the inner pulley since it will run all the time anyway.
That way I can remove the OBW belt when not needed.
It will be real simple to put it on when on the trail.
Less drag for the MPG!


For the bracket it's self. There are a couple other pics in the link at the top of this thread.
One thing I changed was to turn the inner holes on the bracket to slots. That allowed me to adjust the tension on the OBA belt.
If you look you will see the compressor is rotated just a little compared to the AC compressor. Much easier than trying to run a tensioner or idler pully.

Let me know if you need more pics, I may have some from when I built it.

As for the water seperator...I didn't buy one befor I left. I may add one later if it becomes a problem.
One thing I have noticed is the farther from the compressor you put one the better they work.
So I may put a small one just before each bumper to allow the air to cool and condense as much as possible before going into the bumper.

[n2ihc]

How do you tighten the belts from pump to pump?

[Bill usn-1]

For the bracket it's self. There are a couple other pics in the link at the top of this thread.
One thing I changed was to turn the inner holes on the bracket to slots. That allowed me to adjust the tension on the OBA belt.
If you look you will see the compressor is rotated just a little compared to the AC compressor. Much easier than trying to run a tensioner or idler pully.

: thumbsup

[n2ihc]

Reading is fundamental sorry LOL : bonk :

[Bill usn-1]

Originally Posted by n2ihc

Reading is fundamental sorry LOL : bonk :

This is true!!

[Halfbox P]

Bill are you using any kind of oiler on the intake side of your compressor? I'm reading on Kilby's OBA Site that the Sandens need external oil. If not, have you had any sign of premature wear on your pump? I'm considering just squirting some WD40 or other light oil in the intake occasionally. I've almost got my system up and running.