Multigenerational Hodgepodge TJ Engine Accessory Drive

PartyYam

PartyYam

New Member
Joined
Nov 16, 2022
Messages
17
Location
Sumter,SC
2000 Jeep TJ 4.0l Manual Trans. Swapping a 4.0l Titan rebuilt engine into place where a sloppy, sludged out 4.0l used to be. Block numbers before and after are the same and everything is going as swimmingly as it can on a mechanically neglected vehicle. As best as I can tell, the prior owner swapped a junkyard XJ engine before I bought it. The questions arise when i'm bolting the accessories to the front of the block. Seems to be a YJ AC bracket, but everything else is early TJ/XJ? I just don't know anymore, but it all worked before dissassembly!

Should I just put all this back together the way it came apart or is there any value in converting to 2000 TJ parts on the front of this block? The idler pulley on the front of the head snapped off on the old engine so I suppose i'm particularly sensitive to stresses on that part. Some YJ AC brackets have a provision for the idler pulley and some don't soooo......

I care way more about simplicity and reliablity than I do AC so if there's a superior way to build this thing back up, i'm all ears.

ACBracketComparo.jpg


Current AC Bracket:

image016.jpg


Block numbers on new engine (matched old engine):

image017.jpg


Old engine accessory setup:

image001.jpg
 
Is there a difference in the mount? Or are You just concerned about the part number reference? My guess is there were a lot of early TJs running around with the YJ mount.
 
No concern on whether the mount is correct for the year or not; idle curiosity on the design difference of mounting that idler pulley to the AC bracket or straight to the head with the spacer. Just continues to be loads of fun when looking at replacement parts or upgrades since it's different than a 2000 TJ. The primary question was mostly whether there was any reliability benefit to switching over to the 2000 TJ era auto-tensioner, alternator location, and newer water pump design.Nothing like the archaeology process of decoding the variables from previous owners! I'll set it up this way and just keep the AC parts on the shelf (or convert to onboard air if I run out of projects):

Picture credit to board user "Trauma":

img_7592-jpg.jpg


Picture credit to board user "chugchugpickles":

a8dc8f2a-63b0-4df6-99ab-14882e982fce-png.png
 
Just wanted to drop a follow-up for reference in case someone comes into this down the road with a similar bush fix. Looks like the prior owner shaved the idler pulley ear/threaded hole off of this YJ AC bracket. No clearance issues or problems, just non-standard.

YJ AC Bracket p/n is 5300-7602

1677074777640.png
 
The big advantage I see for the newer style alternator location and belt routing is the alternator is up out of the water and mud with the later style mounting. I have a couple friends I wheel with, one has a 99 TJ and the other is a die hard XJ guy. Both of them chew threw alternators...to the point where we have figured out how to take them apart, clean the brushes, and re-install them. Its a big change though, and I don't think the early 4.0L block will support having the Alt up high and the AC compressor on the driver's side like the later 4.0L block does. There are conversion kits out there to swap the A/C compressor with the alternator. When my friends tried to do it, the XJ guy was successful, the TJ guy was not.
 
@PartyYam the photo from ChugChigPickles and the "OEM" bracket in your photo match perfectly with what I had on my '99 TJ that was a factory NO A/C option. I removed the idler and mounted the compressor on top to add A/C to mine. The 2000 models I have seen do not have that idler on that same bracket. It did my head in wandering around the wreckers and seeing multi different versions of the brackets across 98, 99 and 00 models. Long story short - its possible that it is a different bracket from two different years in those photos of yours... assume nothing!
 
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