Engine Swap Compatibility

Oiltech

New member
I recently found a very rusty 1989 Jeep Wrangler with an HO 4.0 Engine. I also own a 1998 Cherokee with a solid body but no oil pressure at idle on a 4.0, HO engine. I was wondering if there are any major differences between the two engines that would make them difficult to swap. I would like to put the 1989 engine into the 1998 Cherokee. Any information would be appreciated. 8)
 

If the only thing wrong with your 98 cherokee is low oil pressure reading at idle I would check and clean or replace your oil pressure sensor. over time they get junk built up in them and will read low to none oil pressure. I have cleaned a few over the years and the oil pressure gauge would start working again. just saying if thats your only problem with the 98 engine.
 
I agree, I used to have a 1990 cherokee with the 4.0 and I had to replace the oil sending unit for that very reason.
 
I agree with others - do not condemn just for low pressure -

so much easier to address than a eng swap...

step 1 put a mechanical gauge on eng to confirm pressure -often a loaner tool.


an old 4.0L, at idle, HOT, poor oil, shitty filter, hi ambient will have single digit pressure. scary but we can work this
 

And if it ends up having low/no oil pressure, just drop the pan and put a new pump.
 
I recently found a very rusty 1989 Jeep Wrangler with an HO 4.0 Engine. I also own a 1998 Cherokee with a solid body but no oil pressure at idle on a 4.0, HO engine. I was wondering if there are any major differences between the two engines that would make them difficult to swap. I would like to put the 1989 engine into the 1998 Cherokee. Any information would be appreciated. 8)

first thing you need to consider your looking at a 10yr difference that said you would need to do a few modifications to make it fit eng mounts located in different spots ,
another consideration is you will be required to bring up the emissions standards from the 89 to the 98 that can get costly . not everything will swap over simple , some modifications will be required the dist will be one of those modifications.
 
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