88 mj head on 2000 xj block

[gnx1117]

Hi guys just wondering if my 88 MJ 4.0 head will work on a 2000 xj?

I basically tore down the motor found cracked head cracked intake on the xj.

Thanks

[Eagle]

Nope.

 

The 2000 XJ uses coil-on-rail ignition. The '88 XJ head doesn't have the bosses to mount the coil rail to.

 

And then, of course, there's the issue of ports not being the same size, shape, or height.

[gnx1117]

Thanks thay will save time and aggravation

[sinkrun]

2000 and 2001 heads had a issue with cracking its all over the net do some searches.  Do not put a 2000-01 head back on, either go newer or older new is direct swap I believe. Older heads can be used some guys run the coil on plug rail without brackets with no issue. I made my own and the head ports do not line up however there is this   http://jeepexhaustadapter.com/ I have used this and it does work I have been running one for 4 years and am getting ready to do another soon. I do not know iif the older renix heads work I used a 96 and A 97 head on mine.

[Rockfrog]

The 87-90 Renix heads had the intake ports 1/8" lower, adding even more mismatch to the problem. Better to find a 7120 or 0630 head for that motor and go forward with that. I run a 7120 head on my '00 but I have the Canadian early emissions version, similar to the US Federal emissions package so I converted to the earlier style exhaust as well.

[75sv1]

Depends. The '88 head will fit. What are you putting it in? If say back into a '00, then as others suggest, get a newer head. The older heads 87 to 95' do not have the dowel holes for the locator pins. You would have to eye ball the centering of the head.

[Rockfrog]

The dowels are a non issue, earlier heads never used them and the pins are on the head so not an issue. They can be simulated by cutting the top off a bolt to make an alignment stud (make 2 or 3) as I did when I dropped a 93 head on my 00 block.

[75sv1]

The dowels are usually not a problem. I had to grind some on a '95 head to get it to position right on my '03 block. I think I am the only one who has had this problem. The pins were on my block.

[Rockfrog]

An '03 block is far different than any ever used in an XJ (or an MJ) ... which still used the '87-98 pattern casting up until 2001 other than some ribbing and metallurgy the basic block barely changed.

The '03 you are talking about would be after the '99 redesign and a lot of changes were made to the 4.0L block at that time.

[gnx1117]

Thanks for all the replies i have decided to pull the 88 engine trans and tc and sell it and rebuild the 2000 xj 4.0.