Someone asked that I make a separate thread out of this, so here is the excerpt from my LJ build thread...
Finally got a chance to work on the OBA setup... I’m a huge fan of engine driven compressors for OBA, and have gone to great lengths in the past to develop mounting systems for them on a myriad of vehicles. With all of the available space in the TJ engine compartment this one was a comparative no brainer, although the mockup phase went through a few evolutions because one of my goals was to maintain the factory alternator bracket and auto tensioner for the serpentine belt. In addition to ensuring proper belt alignment and not overstressing any bearings, it also allows me to have all of the necessary parts on hand to remove the OBA compressor and revert back to the stock belt if necessary. From personal experience, if a compressor seizes or the clutch fails on the trail, it’s nice to be able to revert back to stock and get back to camp without causing undo damage to other parts. At any rate, here are some pics…
The bare 4.0L block and head, ready for some beer and tape measure designing:
Mocking up the final version of the bracket:
The bracket painted and installed:
Here you can see how my bracket simply relocates the factory alternator/tensioner bracket, and provides a mounting shelf for the OBA compressor:
Alternator, idler pulley, and compressor all mounted up:
Since I didn’t change the orientation of the alternator, the factory wiring hooks back up perfectly:
And here is the finished product. Plenty of room for the stock air box, perfect belt alignment and tension, and an endless supply of compressed air ready to go:
I’ll finish up the wiring and plumbing later this week.
Finally got a chance to work on the OBA setup... I’m a huge fan of engine driven compressors for OBA, and have gone to great lengths in the past to develop mounting systems for them on a myriad of vehicles. With all of the available space in the TJ engine compartment this one was a comparative no brainer, although the mockup phase went through a few evolutions because one of my goals was to maintain the factory alternator bracket and auto tensioner for the serpentine belt. In addition to ensuring proper belt alignment and not overstressing any bearings, it also allows me to have all of the necessary parts on hand to remove the OBA compressor and revert back to the stock belt if necessary. From personal experience, if a compressor seizes or the clutch fails on the trail, it’s nice to be able to revert back to stock and get back to camp without causing undo damage to other parts. At any rate, here are some pics…
The bare 4.0L block and head, ready for some beer and tape measure designing:

Mocking up the final version of the bracket:

The bracket painted and installed:

Here you can see how my bracket simply relocates the factory alternator/tensioner bracket, and provides a mounting shelf for the OBA compressor:

Alternator, idler pulley, and compressor all mounted up:

Since I didn’t change the orientation of the alternator, the factory wiring hooks back up perfectly:

And here is the finished product. Plenty of room for the stock air box, perfect belt alignment and tension, and an endless supply of compressed air ready to go:

I’ll finish up the wiring and plumbing later this week.