ruralandalone Posted October 9, 2018 Share Posted October 9, 2018 I am going to rebuild an engine to go into my 86. Not the one that is in it, as I do not want to take it out of service if I can help it. I'm quite happy with my 2.5L I4, and do not need anything bigger. What I was wondering is: 1) I have read that " The 2.5L found in MJ's, XJ's, YJ's, and TJ's was the 150 CU. IN. AMC Rambler. " I have also read that there were "improvements" made to the engine after 86, although I have no idea if there were any significant changes between 86 and 91 Assuming I limit myself to an engine from 86 to 91, is there likely to be any particular difficulty? Are these improvements going to interfere with an engine swap? Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 9, 2018 Share Posted October 9, 2018 Find one out of a 98 Wrangler or a 98 XJ Link to comment Share on other sites More sharing options...
Eagle Posted October 9, 2018 Share Posted October 9, 2018 3 hours ago, ruralandalone said: 1) I have read that " The 2.5L found in MJ's, XJ's, YJ's, and TJ's was the 150 CU. IN. AMC Rambler. " I have also read that there were "improvements" made to the engine after 86, although I have no idea if there were any significant changes between 86 and 91 Assuming I limit myself to an engine from 86 to 91, is there likely to be any particular difficulty? Are these improvements going to interfere with an engine swap? I'm not sure what you mean by "the 150 CU.IN. AMC Rambler," but if you are referring to the engine used in the Eagle SX-4, I'm pretty sure that was a Pontiac Iron Duke. The 2.5L enngine used in the XJs and MJs was a new design, introduced in the 1984 Cherokee XJ. It has nothing in common with any previous AMC engine. I'm not aware of any changes between 86 and 90 that will affect you. You are aware that in model year 1991 they changed from the throttle body injection to multi-port injection, right? So the 91 intake manifold won't the the same as yours. Link to comment Share on other sites More sharing options...
yxmj Posted October 9, 2018 Share Posted October 9, 2018 I have both types The 92 and later is a far better set up to get power and to maintain. Just keep in mind if you change to the newer style you need to make sure you get the harness and the ecu for that motor. Link to comment Share on other sites More sharing options...
gogmorgo Posted October 10, 2018 Share Posted October 10, 2018 From research on this, around '86 or so they changed the size of the head studs, from 7/16" to 1/2" like in the 4.0. Otherwise I've been assured by people who've already posted in this thread that everything is interchangeable between blocks and heads. I've also encountered references to the AMC 2.5 being used in the Eagle Premier, but the AMC Rambler was definitely long gone before the 2.5 came to be. Link to comment Share on other sites More sharing options...
Eagle Posted October 10, 2018 Share Posted October 10, 2018 Curiously, my parts manuals don't include the '84 and '85 XJ, which had a carburetted version of the 2.5L engine. The 86-90 parts manual shows the head part numbers as 8350 2487 for injected, and 8350 2488 for carburetted. The 91-93 parts manual shows me 33000 7115 for the injected head, and 5302 0183 for carburetted. So there was a change in the head from '90 to '91. The head bolts remained the same in the 86-90 parts manual and the 91-93 parts manual. Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 10, 2018 Share Posted October 10, 2018 OP, keep it simple. Find any core from '92 up. There is one change and when you find one report back and I'll tell you how to deal with the one change. You're going to build a long-block...........all you want is a core, find that. Link to comment Share on other sites More sharing options...
ruralandalone Posted October 10, 2018 Author Share Posted October 10, 2018 The Rambler quote was one I found on the jeep forum. I appreciate the clarification. I think I'm likely to keep it simple and stick with the 86 to 90 with TBI. I really don't want to bite off more than I can shew.... Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 10, 2018 Share Posted October 10, 2018 8 minutes ago, ruralandalone said: The Rambler quote was one I found on the jeep forum. I appreciate the clarification. I think I'm likely to keep it simple and stick with the 86 to 90 with TBI. I really don't want to bite off more than I can shew.... You are not going to change anything and I was not suggesting you change anything. Heads and blocks and internals are all the same. Just find a core. You are going to swap all your brackets and accessories and intake over to the new long-block. Just find a core. 92 up also gives you the aluminum valve cover you'll want. If you find a later model engine the only difference will be the crank snout and it's not a problem. Just find a core. Link to comment Share on other sites More sharing options...
Eagle Posted October 10, 2018 Share Posted October 10, 2018 2 hours ago, Jeep Driver said: Heads and blocks and internals are all the same. Just find a core. If the later heads are the same, why do they have different part numbers? Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 10, 2018 Share Posted October 10, 2018 7 hours ago, Eagle said: If the later heads are the same, why do they have different part numbers? The only difference MIGHT be that the temp sender was not drilled and tapped, as the later temp sender was in the stat housing. This was not the case on my '98, mine was drilled, tapped, and plugged. I have a '98 engine with a '92 intake running as a Renix. Certainly, '88 connecting rods will have a different part number from a set of '92 rods from a set of '98 rods but you can set them side by side and they measure exactly the same. Vendors change, castings wear out, materials might change, engineers revamp, carbed to TBI to MPI===engine series change.........any one of 39 reasons why a part number will change over the course of a decade. It does not always mean that the part itself changed. Link to comment Share on other sites More sharing options...
luckycamper Posted September 9, 2022 Share Posted September 9, 2022 On 10/10/2018 at 5:56 AM, Jeep Driver said: I have a '98 engine with a '92 intake running as a Renix. What would one need in order to fit a later 2.5 into a remix comanche? I'm assuming you'd need the harness and ecu. What else would change/what else would one need? Would the sensors be the same? I'm curious about doing this and it would be a huge help to hear from someone who's done it. Link to comment Share on other sites More sharing options...
Eagle Posted September 9, 2022 Share Posted September 9, 2022 Not "remix" -- Renix. Which is an abbreviation -- the early XJ/MJ injection and ignition system was a joint product of Renault (which owned AMC at the time) and Bendix. So they took the REN from Renault and the IX from Bendix ==> Renix. The CPS and flywheel are completely different between the two systems. Link to comment Share on other sites More sharing options...
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