XJ to TJ swap

[john c michael]

Is there any major differences between an early 90's XJ 4.0 and a 99 TJ that would using the XJ motor in my TJ difficult?

[SilverXJ]

That should work. Watch the oil filter adapter (or none) fitment. In 2000 they changed the TJ block significantly, so I would check the accessory and engine mount bosses thoroughly first.

[john c michael]

yes i have been reading alot about that. the oil filter angle and engine mount differences. I have not been able to find any definitive info about the earlier XJ vs TJ blocks. thanks for the advice i will take a close look. i am just starting the build i have striped the XJ block. I am still driving my TJ for now.

[cruiser54]

XJ Cherokee and ZJ Grand Cherokee 4.0L engine blocks interchange.

2000+ TJ Wrangler and WJ Grand Cherokee 4.0L engine blocks interchange.

XJ/ZJ blocks and 2000+ TJ/WJ blocks do not interchange without significant modifications. (1997-1999 4.0L TJ Wrangler blocks will interchange in XJ/ZJ and visa-versa).

TJ/WJ 4.0L Engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand and 2000 TJ Wrangler. These blocks are not interchangeable with XJ/ZJ engine blocks. The reason is motor mount bolt holes and belt driven accessory mounting bolt holes are in different locations, or not present at all, TJ/WJ vs. XJ/ZJ.

[SilverXJ]

Yes, that is how the blocks are technically. But you know how Jeep likes to do those mid year early changes, etc. For instance, on the 2000 XJ they changed the hub/rotor. Some 1999 XJs also got the 2000 hub/rotor change. John, is your TJ a late or early 1999?

Also, where is your AC compressor and alt located? From a quick search those two items are a good indicator if you really have a 1999 block.

[Busey]

I put a XJ block in a 98 TJ no problems- this link shows your 99' having the same casting numbers as the newer blocks
http://www.greatlakes4x4.com/showthread.php?t=661

[SilverXJ]

Where did he post his casting number?

[Busey]

he didn't- I attached a link so he could check his casting number- the info in block FAQ is similar

[john c michael]

Yes, that is how the blocks are technically. But you know how Jeep likes to do those mid year early changes, etc. For instance, on the 2000 XJ they changed the hub/rotor. Some 1999 XJs also got the 2000 hub/rotor change. John, is your TJ a late or early 1999?

Also, where is your AC compressor and alt located? From a quick search those two items are a good indicator if you really have a 1999 block.

the ac compressor and alt are on the right side of the engine by the intake box. i am not sure if late or early and i am traveling so i cant look now. it is a distributer engine which i believe they went to electronic mid year, but am not sure.

[john c michael]

I put a XJ block in a 98 TJ no problems- this link shows your 99' having the same casting numbers as the newer blocks
http://www.greatlakes4x4.com/showthread.php?t=661

thank you for the link as soon as i get back in town i will check it out and verify.

[SilverXJ]

the ac compressor and alt are on the right side of the engine by the intake box.

Sounds like its the earlier block.

[john c michael]

the ac compressor and alt are on the right side of the engine by the intake box.

Sounds like its the earlier block.

thats what i am thinking as well. thanks for your help. i am sure i will have a million other questions as the build gets under way.