amorgan93

Found a good 98 Grand Cherokee 4.0 long block for sale with only 40k miles on it. Wondering if it would fit into my 92 cherokee? What years of cherokee/grand cherokee engines will swap? what are the differences if any? I know my 92 is OBDI while the 98 was OBDII

thanks!

That Jeep Guy XJMJ

pretty sure the head uses a different style exhaust/intake manifold(s). also the block has some small casting differences... most of your bracketry for the accessories are also different. The sensors all have a different harness style connector so those would need to be swapped as well.

cruiser54

I think with a 98 you might be just fine.
Not 100% sure.

You're gonna use your sensors so the electrical portion should not be a problem.

Go to www.rockauto.com and compare part numbers for an intake/exhaust gasket between a 92 an 98. That'll answer the question on manifold compatability.

amorgan93

what about the renesis 4.0? my friend is trying to sell me a 88 cherokee with tranny problems and etc.. but has a good 140k renesis 4.0. how different are they from the HO 4.0 in my 92? will it work?

cherokee94&99

The HO 4.0 block itself is universal as far as i know. I swapped a 4.0 from a 98 larado into a 99 sport no problem. Just hold on to everything else to swap over. Intake, fuel rail and injectors, wiring harness most importantly. I ripped the engine out of the larado and stripped it down to a long block and then just swapped everything over. Taking everything you can off the motor while it's still in the jeep makes pulling it that much easier anyway. Shortest time I've swapped an engine in a cherokee was a weekend and thats only cause i did it on a military base at their auto hobby shop which kicked you out at a certain time or else I'd've had that sucker swapped in a day no problem. Friendly pointer as well whici i wish i would've done while i was doing the swap too. The 90 degree elbow for the oil filter, pull it off and replace that seal cause then tend to leak over time and wen the motor is pulled it's the easiest time to do that. Otherwise if you don't and it leaks the easiest fix with the motor in is to pull the elbow (which sucks) and put a smaller oil filter on.

cruiser54

It's Renix. And it will swap if you use your manifolds, flywheel, dizzy, all your sensors obviously, and maybe valve cover.

amorgan93

sleep deprivation haha so i can use the renix head? Because im 99% sure the head on my HO 4.0 has cracks in it, i wouldnt be comfortable using it. will the ECU adjust for the differences in compression because doesnt the renix have a lower compression? it has 20 less hp stock.

jakbob

i do believe that is because of the head design. not sure though.

cruiser54

Renix head works fine. The ECU could give 2 craps what head is on an HO or vice versa. The HO is not magic by any means. Pretty much a marketing ploy by Chrysler anyway. Go for it.

amorgan93

well i accidentally found some information about the differences in the engines. haha

The principal changes made to make the 242ci engine an "HO" variant are these:
1) Intake ports raised 5/8", reducing the angle that air has to go through to enter the chamber. This makes the head breathe more efficiently.
2) Engine management is OBD-compliant, which makes it a bit easier to tune (RENIX is "pre-OBD.") However, as mentioned, nearly any diagnosis on RENIX can be done with a DMM - there are only a couple of tests that require an analogue. And, I've known OBD to be wrong. I prefer to do my own thinking.
3) The intake manifolds were gradually improved 1991-2007, eliminating right-angle bends and sharp corners (both of which improve airflow.)
4) The knock sensor (found on RENIX) was deleted for 1991.
5) The EGR valve (never really needed on these engines anyhow) was deleted for 1991.


seems like the swap would be a little more difficult than i thought. not sure though

Cherockee

Why are you going from looking at a '98 block to an '88? The '98 block will be the best choice. Only thing you'll have to change are the sensors on the intake and TB. Everything else will work fine, if not better.

Run away from the '88 block, not worth it IMO. Especailly since there are plenty of '92+ motors out there waiting to be transplanted.

cruiser54

Not 5/8" on the ports. More like 5/16", if that.

dcurre1

Excuse the side tangent from me here but I’m curious about swapping in a 92 engine and maybe drive train into my 88. I was given a clean 88 shell body with transmission and no engine and I’m trying to find the most simple and effective swap. Found a complete drivetrain from a 92 Cherokee and wanted to know if this is a good move. Thanks and thanks for your patience with a new Cherokee owner.

cruiser54

Just swap the 92 motor in using my write-up as a guide.

https://cruiser54.com/?p=100