'00 engine into '87 xj

Hey there! First off, wanted to introduce myself.... I'm Melanie from PA... newish to XJ's have had CJ's for a while now. Have an XJ that I raced in the last TREC race. It is an '87 and it has a really tired stock (non-HO) 4.0L engine.

We have the opportunity to pick up a wrecked '00 XJ that has a good engine & tranny. I was wondering the following things:

1. Any issues swapping the engine into the '87.. the jeep is whole so we would have access to the whole wiring harness etc.

2. Someone we know mentioned that it has a different fuel pump.. would using the gas tank we have with the fuel pump with it be a problem with the '00 engine? We have a skid on it, and from what I understand the '00 would have a differnet gas tank that would not work with the skid we have.

3. Any issue mating the engine up to the existing transmission, I am under the impression all XJ autos are the AW-4

Anything else I should know about the '00 engine? Is it a good/bad choice?

The '00 would have a Low Pinion D30 front with the bigger joints correct (rather than high pinion). We haven't seen the jeep yet, just got a phone call about it.

Thanks for your help
-Mel

Most newer engine into Renix swaps involve keeping Renix electronics and using the new engine. However, I believe the 00 would have the distributorless ignition, and I don't know if this engine would have a hole for the Renix distributor in. If it is indeed impossible to fit a dist. to this engine, the only option would be to swap the computers and every bit of wiring from the '00 into the '87.

As far as the transmission is concerned, the flywheel or flexplate must match the electronics being used, or it will not run. I don't know about the wiring connectors for the AW4 in a '00, so they may or may not be the same, I know 91-95 plugs in fine to the 87-90 wireing. The other problem you may run into is the transmission connecting to the TC, because at some point(I forget when) the spline count was changed. There is information on here about swapping the shafts to connect trans/tc of different years.

the 00 has the bad head doesn't it?

00 has 0331 head, which is said to be prone to cracking.

The '00 has the same hole for the distributor. It is used for the cam position sensor. 0331 is the bad head for cracking. Look for milky residue on the bottom of the oil fill cap.

I would say that these guys have ya covered for the most part on your questions, I was just going to follow up on the D30. It (the 00) will have a LP in it w/ the 297 joints/shafts. I personally would take the shafts out of the LP unit and swap them into your HP housing. Reason being is that chances are you have a disco axle housing and you have the 2 piece passenger side shaft in it. That housing is stronger due to the cast upper control arm bracket verses the stamped steel one that is on the non-disco axles. You will also retain the other benefits of the HP housing that way. You could consider putting the knuckles,calipers etc off the LP housing onto your HP housing, but that is your call.

Thanks folks.

Any comments in regard to the '87 tank/fuel pump working with the '00 engine? Is it a non-issue?

The "prone to cracking" is that a "pretty much always" happens, or a "you hear it a decent amount, but it is no guarantee"

The '87 I have had a non-disco front axle, and has already been upgraded with the improved shafts and heavy duty 297x u-joints... but those shafts would make slip-in spares I would assume.

Basic opinion... '00 swap into '87 XJ... good or bad idea.

-Mel

I'm pretty sure the fuel pumps ran at different pressures. I think the Haynes manual has that in it if you have one.