Jump to content

2000 XJ motor in a 1989 MJ


Recommended Posts

In the coming weeks, I'm going to be swapping in a 4.0L motor that I have from a 2000 XJ into my 1989 MJ project I've been slowly working on. I plan to use all of the Renix electronics/sensors from the original motor so as to hopefully have a "turn-key" solution. However, upon reading some post about newer engines in older trucks, I realized that may not be so easy. So, I figured you guys could help me out here so I don't miss something silly. So far, I've read that I must use the original flywheel as the newer one will not be compatible with the older Renix CPS. Ok, fine, but will the older style flywheel bolt right up to the '00 crank? I thought I read somewhere that the crank dimensions are slightly different and require a specially machined bushing if they are to be interchanged.

 

Also, at the time of the swap, I'm going to be looking to replace the original BA10 transmission with an AX15. I'll do my best to find the external slave cylinder bellhousing out of later model XJs.

 

So, if there is anything else that needs to be addressed, please let me know so I can take care of it BEFORE I dive into the swap :)

 

Thanks in advance!

Link to comment
Share on other sites

It's really not gonna work. Not only will you have sensor incompatability, the ports on the manifolds will not line, up, and, IIRC, the 2000+ 4.0s use a distributorless ignition. IE, coil packs.

 

If you don't plan on changing any wiring, you need to just find another Renix motor.

Link to comment
Share on other sites

It's really not gonna work. Not only will you have sensor incompatability, the ports on the manifolds will not line, up, and, IIRC, the 2000+ 4.0s use a distributorless ignition. IE, coil packs.

 

If you don't plan on changing any wiring, you need to just find another Renix motor.

 

Every sensor from the Renix system would be retained and used in one place or another, even if it means I have to modify certain components. I'd definitely reuse the old distributor in place of the camshaft position sensor/coilpacks - I see no reason why I couldn't get that to work.

 

On the subject of the manifold ports. The 2000+ heads use smaller exhaust ports, but the bolt pattern for mounting is identical to my 1989 head. I haven't looked into intake compatibility yet, but I was planning on using the '89 intake manifold to retain all of the sensors.

 

I also wouldn't be opposed to ditching the '00 cylinder head (since it's prone to cracking) and reusing the '89 head (after a rebuild).

Link to comment
Share on other sites

Then why even bother with the 2000 block?

 

Because it was given to me from a friend and it ran great. Compression is solid all across the board and it passed a leakdown test with flying colors. His truck had about 85k miles on it before it got hit hard and was totaled by the insurance company.

 

Now, the engine in my '89 MJ is tired...REALLY tired. It had a problem with leaking injectors after engine shutdown where fuel contaminated the crankcase oil to the point where the oil was coming out thinner than water when it was drained. The bearings are shot, the rings are shot, compression is all over the place, it FAILS a leakdown test, and it has more blow-by than I've ever seen. OH, the oil pressure isn't that great, either. There are plenty more reasons why I'd like to ditch this engine, but I think I've provided enough! ;)

Link to comment
Share on other sites

I'll agree that your '89 engine is shot, But.......your jumping 2 generations in engines here, the 2nd generation 4.0 ('91 - '96) would be a better choice for a swap, like Geonovast wrote, you have the coil packs on the 3rd generation engine, yea, you can get around that, but think about the engineering that went into that change, and your going back 10+ years, what else was changed....... :hmm:

 

Also, what are you planing on using for the drive train??? The Renix transmission, or the newer Chrysler tranny??? The 3rd generation auto tranny will not work with the Renix era system.

 

There are plenty of good used 4.0's out there, both the Renix and the Chrysler (2nd generation)

 

Just don't get and engine from one of them C4C :teehee:

Link to comment
Share on other sites

I have 25k miles on a 00 xj engine swap in my 88 mj. I reused all my renix injection parts, and all the accessory stuff from my 88. The dist will go in no problem,and the 88 flex plate went on without a hitch. Now mine is a aw4, so I'm not sure on the manual trans. If its diff take your 88 crank and have it turned, and add new bearings and put it in the 01 block. The cranks are easily swapped. I also added ford 19lb injectors, and remember to swap your oil filter housing too. The threads are diff on the 91 and up oil filters. Hope this helps, anymore questions you can email me @ qwk2race@aol.com. By the way guys I'm new here, just found this last night. Cool site though.

Link to comment
Share on other sites

I have 25k miles on a 00 xj engine swap in my 88 mj. I reused all my renix injection parts, and all the accessory stuff from my 88. The dist will go in no problem,and the 88 flex plate went on without a hitch. Now mine is a aw4, so I'm not sure on the manual trans. If its diff take your 88 crank and have it turned, and add new bearings and put it in the 01 block. The cranks are easily swapped. I also added ford 19lb injectors, and remember to swap your oil filter housing too. The threads are diff on the 91 and up oil filters. Hope this helps, anymore questions you can email me @ qwk2race@aol.com. By the way guys I'm new here, just found this last night. Cool site though.

 

Cool! Thanks for the advice on the oil filter housing - didn't know that one. I'm definitely going to add the Ford injectors as I've heard nothing but good things about them and the fella that sells them.

Link to comment
Share on other sites

Found where I read that from, four wheeler magazine's stroker build article

 

We learned the hard way that not all Four-O's are created equal. Our engine was destined for a 2000 Wrangler. The low-mileage original engine was being saved for another purpose, so a used engine from the early '90s was procured. We learned the hard way that there are significant external differences between the '00-and-later engines ('99-and-later for the WJ) and the earlier ones. Eye exams for all were ordered. It was as obvious as a garish Aloha shirt at a funeral. Water pumps, accessory mounting, engine mounts, induction systems, and more-all changed. Installing an older engine into a newer rig, or vice versa, involves adaptation-doable but adding to the financial burden. The best advice is to start with your original engine or a similar year range.

 

Now this is an article about TJs so it may be different for the XJ/MJ... Seeing as it has been done before I may be totally wrong, but I'd just advise you to check

 

Good hunting

Link to comment
Share on other sites

Now this is an article about TJs so it may be different for the XJ/MJ... Seeing as it has been done before I may be totally wrong, but I'd just advise you to check

 

Good hunting

 

Thanks for the excerpt from that article! I have the donor engine up on a stand and rolled it close to the MJ engine bay so I could do a back-and-forth check to make sure all of the mounting points are identical. From what I can tell - which is hindered by the fact the engine in the MJ is all bolted up and accessories are in the way - most of the mounting points are there. There are, however, a couple that I'm concerned about - one being the coolant temperature sensor on the Renix vs. the '00 XJ engine, but I think I can get around that by using the newer style sensor location on the thermostat housing. There is another sensor on the drivers side of the engine near the bottom by the oil pan. I'm not quite sure what it is or if it penetrates all the way through the block. If it doesn't, I think I'm fine as my '00 block has a threaded hole in that location, but it was never used by the newer '00 XJ electronics (as is evident by the rust buildup in the hole).

Link to comment
Share on other sites

99 and later WJ and TJ blocks are diff. They have motor mount castings in diff places, and they use totally diff acc mounting holes. Don't ask me how I know this, as I bought one for my mj, and tried to bolt it in, wrong it wouldn't work.Salvage yard wouldn't take it back, so I had to sell it on craigslist for a loss, and buy another. All 4.0l 87 to 01 xj blocks will mount in the original location in a xj or mj. The 91 and later 4.0's had a boss cast in the right side of the block to mount the coil. Thats the major diff from the 87-90 and the 91 and ups.I think in 97, if I remember correctly the 4.0l's got a steel main cap brace, but just minor changes after that.I think in 98 or 99 they started using skirt coated pistons, to do away with piston slap.If you look on the pass side of the block, each cyl will be marked with a grease pencil with a letter. This is the final bore size, and they are never all the same. Its A,B,C, and D if I remember, and you can buy pistons in that size but you had to know the letter.If you bought a replacement piston, it came on the rod, ready to go. They say the heads are diff, and they might be, but I have used non ho heads on ho blocks. I've also used ho heads on non ho blocks, with no trouble. I worked at a jeep dealer for 15 years, and saw the changes first hand, I have also owned so many xj's and changed the motors in most of them, that I don't dare to count. Its such a shame they dropped that fantastic motor...Oh well good luck.

Link to comment
Share on other sites

On the sensors as well, the one near the oil pan is the knock sensor, and it can be added to the 00 engine. There is a threaded plug there, just remove and install the sensor. I'm not sure on the coolant sensor though, mine had a spot for it at the back of the head, just like the 88 motor. On the 19lb injectors, go to the salvage yard and pull them out of any 4.9l 6 cyl or 302 with multi-point injection.They will be orange, and take a old jeep one to verify the connection. Mine were out of a friends 91 mustang, when he upgraded to bigger units.

Link to comment
Share on other sites

Hey qwk2race - thanks a lot for that information. In my research, I've always found little bits and pieces of how the 4.0L block changed throughout the years (as well as throughout the Jeep models), but the info was always very vague with statements like, "the accessory mounts changed" or "the heads are different." It's nice to get finally have someone with first-hand experience chime in on what they know - so thank you for that.

 

I know for sure that the cylinder heads are different on the '88 motor vs. the '00 motor. The '00 motor has the undesirable 0331 casting, which has had more than its share of failures (it will crack between the 3 and 4 exhaust ports). I'm not quite sure what cylinder head the '88 motor has nor do I care since it's getting scrapped. The only thing I'm concerned about is that the bolt pattern for the intake/exhaust manifolds on both motors are identical - and I'm 99.99% sure that they are. The intake and exhaust ports may be of different sizes on both years, but I'm not too worried about that. I'll fabricate an adapter plate if need be - I've done it to my '01 XJ that now has a '98 XJ motor in it (the exhaust ports on the '98 motor were too large for the '01 header).

 

One of my main concerns was the crankshaft - in doing my research I ran across a couple of fellas that believe the crankshafts changed throughout the years - specifically where the flywheel/flexplate/clutch bolts to the end.

 

Also, thanks for the tip on the fuel injectors. I'll most likely stick with the ones from Precision Auto Injectors because they are cleaned and come with a certification of flow matching to within 1%. I struggled through months of trying to tune another car of mine where I took a gamble and bought injectors that may or may not have been flow matched. I could never quite get the proper mixture at WOT and I wound up tracing it back to the injectors. While I won't be doing ANY tuning on this particular engine, that whole ordeal has left enough of a scar in my memory to never travel down that route again.

Link to comment
Share on other sites

I understand on the injectors, I'm just cheap, and the ones I got were free. My 88 had the same problem as yours, where the injectors were leaking so bad, it washed down the cyl walls. I know the cranks will interchange, I had a good 94 crank that I sold to a friend with a 01 tj, and it went in no problem. You will just have to pull your 88 crank out and compare it to the 00. I tossed my last non ho block and crank about a month ago, or I would check for ya. I have a 97 xj motor on a stand now thats getting rebuilt, that has the crank out. I could of placed the 88 crank in it for you to check...Oh well

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...