Lets dig up an old thread and add more information. Thank Google for finding this. Here's the deal. My 94 XJ just suffered some grotesque metal fatigue in the #1 connecting rod and added a nice window to the block. What can one expect from the original engine with 500000+ miles. Should have replaces all the rods when I rebuilt it 4 years ago. I found a nice clean 4.0l to replace it. Either the engine just had a recent rebuild or it's had a sweet life of regular oil changes. The problem is, the engine is from a 2002 WJ.
Since everyone says the WJ 4.0 is not interchangeable with the XJ 4.0 without giving details about what the changes are, except that it "was a clean sheet revision" blah blah blah.. BS
Here are the changes for anyone who cares. As far as the mount bosses for the engine mounts goes. The bosses are present and tapped on my 2002 block, but here's the catch:
Passenger side: the forward bolt/boss is to short. A spacer and loner bolt is needed. The boss was shortened to allow clearance for the WJ motor mounts.
Driver's side: the rear bolt/boss is a little to proud/long for the XJ motor mount bracket to fit properly. This is where the WJ mount bolts up. It is tapped for a metric bolt.
Since the XJ was discontinued in 2001, here are some things not drilled and tapped on the block.
Water pump bolt hole @ 3 o'clock position. The boss is present, but not drilled.
Two bolt holes to mount the power steering pump bracket to the block (driver's side).
I'll have to test fit the Alt and A/C brackets to the passenger side to see if any bosses are missing or not tapped.
The boss is preset for the coil, but not drilled and tapped. The oil pressure sender was moved from the oil filter boss, back to the rear of the engine.
There's new bosses for the WJ motor mounts on both sides.
The engine came with the intake and exhaust manifolds, but not using then since it's a PITA to get the older power steering pump brackets to bolt up. Also, not a fan of the stamped metal valve cover.
Most of the changes to the WJ block are to incorporate the stupidly large engine mounts and the deletion of XJ specific drillings.
Hope this helps clear up "it wont work" diatribe I keep seeing from Cruiser54 across multiple forums. Not making a personal attack, just your the one who posts the good information about the compatibility of the blocks. Just wish someone would have said earlier what the exact changes were. I'm going ot go visit my old block and take pictures and post comparison pictures between XJ and WJ blocks.
Cheers,
Marcus