Landoloops Posted February 1, 2007 Share Posted February 1, 2007 Alright most of you are probably sick of the 86'er guys (who could also be refered to as the guys not smart enough just to buy an 87+ to begin with) talking about this swap and that swap trying to get rid of the dog that it is 2.8l v6. But I have a few questions and requests to those select few who have done the 2.8 to 4.0 swap. (Minydigger, derjeager, Scott86mj... anybody else?) Could you give a brief write up on your swap. The parts i'm most interested in are: the radiator cross arm hood catch and release, did you use the xj hood? any pictures of areas in the engine bay any things you had difficulties with that your experience would help ease the next guys difficulties. What year the donor XJ was Pictures would be awesome. I've been reading up for some time on the swap an just started it myself, the 904 tranny had just gone out on my MJ so I just picked up a rolled 95 XJ with a 4.0 and AW4 for $300. Here is my MJ Here are some links to projects that i found while researching Scott86mj's Project http://comancheclub.com/forums/viewtopic.php?t=1965&postdays=0&postorder=asc&highlight=engine+swap&start=0 MinyDigger's Project http://www.comancheclub.com/forums/viewtopic.php?t=1272&highlight= Link to comment Share on other sites More sharing options...
Scott86mj Posted February 3, 2007 Share Posted February 3, 2007 My conversion was from 2.5 to 4.0 but the only difference should be, you will need a new fuel tank I think unless the fuel sending unit will fit in your tank. I t has been a while since I did mine but I will try to help.I used a 94 xj sport with aw4 and np231. My original tranny was a column shift and the aw4 was floor shift. All I had to do for that was remove the plate covering the hole and the floor shifter bolted right in. I had to drill a hole with a hole saw for the trans linkage. I used the radiator support ,hood, radiator, condensor steering column,heat/ac unit, complete wiring harness and fuse panel from the xj. I did have to modify the stop lamp switch to use my brake pedal the hole on the mj was to big for the xj stop lamp switch it might be easier to use the xj brake pedal assembly but I had already hauled the xj off when I got to this part. The trans cross member had to be moved back about 5 inches and the rear drive shaft shortened. The motor mounts just bolted right in. I had to drill new hole s to attach most ever thing like the ecm and radiator over flow bottle and relay box. I removed the engine trans and tc as 1 unit and unhooked as little as possible and labeled anything I had to unhook. Hope this helps you get started. If you have any question let me know. It isnt that hard just time consuming and it is well worth it. Link to comment Share on other sites More sharing options...
Eagle Posted February 3, 2007 Share Posted February 3, 2007 Scott -- What about the firewall? Did you have to modify (as in hammer) that at all? Link to comment Share on other sites More sharing options...
Scott86mj Posted February 3, 2007 Share Posted February 3, 2007 No, no modifications to firewall other than drilling holes for the trans linkage and the trans controller wiring becouse I wanted it mounted inside. My 86 was built in oct 85 so I don't know when the firewall was changed but mine fit just fine. Link to comment Share on other sites More sharing options...
1986Comanche Posted February 4, 2007 Share Posted February 4, 2007 No, no modifications to firewall other than drilling holes for the trans linkage and the trans controller wiring becouse I wanted it mounted inside. My 86 was built in oct 85 so I don't know when the firewall was changed but mine fit just fine. How did you find out when your 1986 was built? I would like to find out when my 1986 was built. Link to comment Share on other sites More sharing options...
Scott86mj Posted February 4, 2007 Share Posted February 4, 2007 No, no modifications to firewall other than drilling holes for the trans linkage and the trans controller wiring becouse I wanted it mounted inside. My 86 was built in oct 85 so I don't know when the firewall was changed but mine fit just fine. How did you find out when your 1986 was built? I would like to find out when my 1986 was built. It has a sticker in the drivers door. Link to comment Share on other sites More sharing options...
jage Posted February 5, 2007 Share Posted February 5, 2007 Join the club. If I'd know then what I know now I'd've never bought a 2.8. I did the 3.4L swap and it was well worth it. I paid somebody but that's the same block and the parts (alternator etc) bolt right on. Notwithstanding that, I've read on this board that all MJs have the correct firewall for the 4.0L, something about when they were produced Jeep was already going with the 4.0 in the future and the fw mod was put in the MJs even with the 2.8. As far as my XJ 2.8 the other problem was the tranny mount was like 14 inches different than the 4.0/2.5s from 87 on, so check that out. Link to comment Share on other sites More sharing options...
Landoloops Posted February 12, 2007 Author Share Posted February 12, 2007 Well, I am about 90% done with my swap, I have a few odds and ends to take care of and I'll be done. I still need to -Rewire the plugs that go to the rear of the truck (Fuel Pump/Sender, Brake/Tail/Blinkers/etc) -Move the tranny support back -Shorten the Drive shaft -Connect the brakes (I need new lines to go to the distributor block) -Install a 97+ Front end (the cherokee i bought had front end damage) It seems as if its been going really well but I'll have to wait at least until i get the fuel pump connected so I can see if I did everything right. I pulled the fuel pump/sending unit out of the xj tank and it fit right into the mj tank so hopefully that will work out, hopefully i'll find out tonight. Scott86MJ what did you do for your tranny support bracket, I have some ideas, I was just wondering what you did? Landon Link to comment Share on other sites More sharing options...
harris1986 Posted June 22, 2017 Share Posted June 22, 2017 Any update on this? I'm doing the 2.8 to 4.0 on my 86 and really want to know what to be prepared for... Link to comment Share on other sites More sharing options...
harris1986 Posted August 3, 2018 Share Posted August 3, 2018 Bought a working 89 XJ 4x4 with 4.0 IL6, Now to start on the conversion of ripping this out and installing it into my 86 MJ Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 3, 2018 Share Posted August 3, 2018 20 minutes ago, harris1986 said: Bought a working 89 XJ 4x4 with 4.0 IL6, Now to start on the conversion of ripping this out and installing it into my 86 MJ You should start your own build thread. This one is from early 2007... Link to comment Share on other sites More sharing options...
Eagle Posted August 3, 2018 Share Posted August 3, 2018 This thread is ELEVEN YEARS old. Closed! Link to comment Share on other sites More sharing options...
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