I have read so many items pro and con on this that I decided to post on this site where hopefully some folks that have done this can shed some "hands on" experinces. I own a 99 grand cherokee with a 4.0 (bad engine) I want to replace this. Can someone shed some light on the different years that will work, I'd rather not have to drill and tap holes in the block. Thanks so much in advance!

 

Honestly if you have an engine from a 99 xj ( stated in title ) then I don't see how you would have an issue. I believe ( will go and check on a 99 wj ) but the mounting should all be the same. Computers and sensors will be all there as well. Hope this helps you.

 

There was a change in the block casting which the OP seems aware of.. he hinted about tapping the block.

From what i understand, you need a WJ or 01+ TJ engine. I'd suggest looking for 04+ with the newer designed 0331 cylinder head.

 

x2... i've looked into swapping a WJ engine into my XJ, for the re-designed accessory mounting... belt drive accessories are significantly different... on the 99+ WJ 4.0, power steering pump/pulley is in the same location as 99-01 XJ, but A/C pulley is located under the PS, alternator is relocated to the top (where the XJ A/C pulley is), a new tensioner assembly sits under the alternator, & no mechanical fan pulley...



99-01 XJ...

 

The WJ to XJ swap can be done, you'll need BrownDog conversion engine mounts. I'm not sure exactly what's required for waterpump and accessories however.. a search at NAXJA will bring up a thread where it's been documented.

Once BrownDog gets the conversion mounts done for the XJ to WJ this swap will be possible, but they need someone to drop off a WJ for prototyping the bracket kit last i spoke with them.

 

are you saying a WJ 4.0 INTO an XJ? or the OP's question, an XJ 4.0 into a WJ?... as for WJ into XJ, yep, i've seen it in person... i want to say waterpump is the same... changes would be with what i mentioned above... it would be easiest to use the 99-04 WJ 4.0, or 01-06 TJ 4.0, to not have tap new mounts into the block/head... & like u said, the re-designed 04+ head

besides motor mounts, A/C lines need to be re-routed, if keeping A/C (could possibly keep the idle pulley, or convert to OBA) & 99+ 4.0's have coil packs instead of distributor (in my 98, i'd need to modify), & since mechanical fan is eliminated, new electric fan needs to be installed

opposite for the OP, if he uses an XJ 4.0... might be easier to re-route A/C lines, use a 99+ to have coil packs, remove mechanical fan... but IMHO, i'd say the WJ or 01-06 TJ 4.0 is a better choice

 

The block castings differ between the two and the motor mounts won't line up, otherwise their identical.

 

I thought the biggest thing was the coil pack mounts vs. distributor, otherwise most late model 4.0L could be swapped. (many have made up brackets to mount the coil pack)

After much research I ended up pulling my motor and replacing the cam bearings which were trashed from the crappy 0331 head problems.

Good Luck,

Bryan