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Questions about swapping different year/model 4.0s

My 98 cherokee HO 4.0 lost compression on the middle two cylinders recently. I have an 87 renix cherokee that I pulled the engine out of. Can I easily put this in my 98? Just by looking I notice there is no coil mount holes on the 87 engine. How do I over come that? Any other problems? Or just don’t do it? Or?
 
I have a 98 xj 4.0 L the oil filter screws directly onto the engine block as opposed to the leak prone oil filter adapter also the oil pressure sending unit screws into a brass fitting on the side of the block I"m thinking this engine is from a zj according to info in this post.
 
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
 
I started down the WJ 4.0L rabbit hole about 2004 or so. I did get it installed into my '88 Comanche. I did a spacer on the passenger side and cut and welded the driver's side bracket.
I did sell off the Tupy head. I stopped about there. Brown Dog does advertise swap motor mounts.
If I had not sold off the head, I would think about retaining the WJ accessory drive, and use electric fans. I do run 3 10" SPALs on my '00 XJ. Seems to do OK.
Through my ever changing builds, the 4.6L stroker from Russ Pottenger is going into the '88 MJ. Also, I took a LS 5.3 block to be machined , yesterday.
I also wonder about it being a clean slate design. Yes, I have worked in engine design as a drafter. I've seen more design changes on a part being called a revision.
 
Besides the untapped/changed bosses, I noticed the oil filter boss was raised higher on the block. Bye troublesome oil filter adapter.
 
Besides the untapped/changed bosses, I noticed the oil filter boss was raised higher on the block. Bye troublesome oil filter adapter.
 
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