Noltz

I finally got one of those "I should have this" projects finished up - my OBA system. And, with lots of pictures! Enjoy,

Started with a 7 gallon tank that got tossed due to a bent air valve on it;


I cut off the feet and handle with a 3" wheel, leaving me with a solid little tank. I would not compromise the interior space, so the tank was going to be mounted under the truck. Using torches, I cut off the spare tire brackets, and the inoperative tire winch;


Then I checked my clearances by mocking up the mounted tank. I had to move the tank a few times to get it just right.




Fabricating the actual brackets to hold the tank was actually rather easy. Canadian Tire (CTC) sells these wonderful strapping brackets for ~ $5.00 each;




Applied a little rocker guard to the brackets for that new car smell .




And switch out the air control switch for an open tee.
...I ended up swapping this ½" unit for a 3/8's piece because I could not get enough ½" line at the time.


---------------------------------------------

With the tank was mounted up, I moved to the front. This truck came without A/C - a blessing in disguise for this install. A trip to B&D Auto Wreckers netted me a compressor, brackets, lines and a belt for $40. So, on to the install:

The guts,


The previously un-occupied spot on the block,


Bracket mounted,


Compressor's in,


Add a tensioner and a belt, and your transplant is done!


Next I must feed this compressor fresh air, and route it's happy, compressed exhaust appropriately. I started by adding a ½ barbed fitting to the intake of the compressor;


And added a stretch of black industrial water hose to that, crossing over the fan shroud, and tapping into the filter air line as shown;




It was my original intention to draw oil vapours from the PCV system to lubricate the compressor. After setting it up and running it for a few moments, it was audibly clear that the PCV draw system wasn't going to cut it. The compressor was making a little more noise than normal, and I didn't like it. So I capped off the draw line, and reinstalled the original PCV system. Currently, I have a 300ml bottle of air tool oil under the hood, and the intake of the compressor is easily accessible to add a few drops. It's temporary, but the compressor is much happier now. I spoke recently with a few other OBA installers, who all recommended a low-cost inline oiler on the intake line. They boast not having to fill it often at all ("I top it up with my oil changes"), so it'll be perfect for me.

---------------------------------------------

With the two big pieces mounted, I moved on to connecting the system together. The shop at CTC uses 3/8" hose that we purchase in bulk, and add our own fittings to the ends. Upside is when someone drops slag onto a line, that 25' section is tossed and replaced. I scooped one that still had enough solid line for my uses. Tied together with fuel injection line clamps, I the system came out leak free!

This is the main line. I may switch this out to a ½" section, to get more flow to the front of the truck.


Run across the top of the RHS frame rail, secured to the brake lines as needed,


Up against the firewall, into the engine compartment,




In the last picture, you can see the discharge line off the compressor, and the yellow tank line feeding up from the tank. The discharge line is 10mm, heavy wall aluminum - not the easiest thing to hook up to. I cut off the factory condenser fitting. Then, I brazed a 3/8 barbed fitting to a 3/8 OD pipe compression fitting, and snugged it onto the line. Remarkably, there were no leaks! I had to file down the threads of the barb to get it to seat inside the compression fitting.






---------------------------------------------

One of the hardest parts was actually choosing where to mount the quick-connect. After staring for a good half hour, and circling the truck at least a dozen times, I decided to get'er done and tuck it into the grill. I may still add a second connect at the rear. One of my ideas was to sink it into the cubby hole behind the wheel wells. Perhaps later... on with the install!

A piece of ¼" stock was heated and bent to become the bracket;




Pulled the grill at this point to do the mounting & trimming for clearance;




Damn sexy piece if you ask me


Took about 8 trial fits to get it as tight as possible. A dremel with a cylinder stone is vital here.




And finally,


---------------------------------------------

The anticipation of getting it done was getting to me. A trip to Princess Auto yielded the pressure switch and manifold;



I hooked up a short section of line to the quick connect, and routed it to the manifold area,


After assembling the manifold, the hoses were connected. Left to right are the pressure switch (not installed at time of photo), Tank line, quick-connect line, and the compressor discharge line. Obviously, the gauge is mounted on top.


I left enough line that I can raise the manifold about 5" above the battery / radiator for service or repairs. The manifold itself is tucked down and secured to the washer fluid bottle bracket during normal service. This places the gauge just about level with the washer reservoir cap.


With all the lines hooked up, I manually tripped the clutch to test my system;



The pressure switch was mounted high under the dash, behind the glove box. It is not serviceable up there without removing the box itself, so a remote switch had to be added to control the system. I chose to put it in the change tray in front of the shifter.







And that's that! After buttoning everything up, I flipped the switch on. The compressor fired up, and brought the 7ga tank from 0 to 100psi in about 1 minute, at idle. Speeding the engine up to 2000 cuts that down to about 25-30 seconds. With the engine at 1200, I can use my impact gun to remove six lugs, and it's still at 120psi when I get back to the gauge. A blower tip or die grinder would probably be the only thing necessary to kick up the engine speed above idle for. The rest are all intermittent tools and the compressor can more than keep up with those.

Changes I would make would be running ½" line from the tank up. It might be expensive, but I think I'd get more 'umph' from the gun with the additional flow. I would also get a manifold that has mounting brackets, instead of relying on a pair of zip ties. I would (and will) relocate the gauge inside the cab (tee off the pressure switch line), and replace the under hood gauge with a safety valve. Other than that, I'm very happy to have it installed and look forward to using it.

Thanks to DVS from Jeepkings for the help with the pressure switch question, and to my apprentice Josh who kept turning the wrenches while I was sitting at my bench thinking this thing up .

__________________