4.0 interchangeability

Joshman3280

New member
Hi everyone, so I need to pick everyone's brains! I am faced with a bit of a dilemma so here it goes. I have a 92 XJ that's equipped with a 4.0 H.O, it has 270k miles on it and failed Washoe county smog due to smoke off idle so my shot at classic vehicle registration is gone till next year. With that being said the 92 has excessive rust issues so not sure if it is worth putting more money into it. I bought a 90 XJ about a year ago from a young gal who overheated it and lost compression in number 4 cylinder. She didn't want to fix it and so I saw the opportunity to have a project jeep with my daughter and family, well it has been sitting in my driveway for a year and I am now considering getting it going and scraping the 92. The 90 XJ has NON H.O 4.0 Renix system. The 90 has virtually no rust and only 160k miles on drivetrain, also it has the aw4 automatic trans and power windows etc. the 92 is manual and strip down model lol. So I can only find a used engine locally that is from a 97 XJ. If I reuse the intake and distributor would I be good or does anyone know if I will run into mounting issues? Like engine brackets and accessory mounting holes? Also what about sensor location issues. I know it's a backward swap most people go from Renix to H.O but considering the conditions of the jeeps it makes more sense to put money into the 90 over the 92. Any thoughts advice or suggestions would be appreciated thanks again!


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Joshman3280

New member
Well I thought that as well, I pulled the head off the 90 and found sever scoring on the block on #4 cylinder wall. I assume rings came apart. I am considering the 90 engine a complete loss at this point. The head actually looks good.


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Clifford98

New member
You can use the motor you just need to swap over all accessories including the manifold, sensors, and distributor also you need to make sure you use the correct flex plate / flywheel (the one for the year vehicle it is in) if not it will not start. I’ve done the swap both ways a couple times it’s pretty straight forward


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IgotaWoody39

New member
Go to the thread " 1998 4.0l " thread, I inserted links to full service manuals, tech manuals, torque specs, part specs, evrything on the xjs 84 thru 2001....there's also a second link too enginebuilders dot com, they have the run down on the heads used on those years as well....good luck..


Hi everyone, so I need to pick everyone's brains! I am faced with a bit of a dilemma so here it goes. I have a 92 XJ that's equipped with a 4.0 H.O, it has 270k miles on it and failed Washoe county smog due to smoke off idle so my shot at classic vehicle registration is gone till next year. With that being said the 92 has excessive rust issues so not sure if it is worth putting more money into it. I bought a 90 XJ about a year ago from a young gal who overheated it and lost compression in number 4 cylinder. She didn't want to fix it and so I saw the opportunity to have a project jeep with my daughter and family, well it has been sitting in my driveway for a year and I am now considering getting it going and scraping the 92. The 90 XJ has NON H.O 4.0 Renix system. The 90 has virtually no rust and only 160k miles on drivetrain, also it has the aw4 automatic trans and power windows etc. the 92 is manual and strip down model lol. So I can only find a used engine locally that is from a 97 XJ. If I reuse the intake and distributor would I be good or does anyone know if I will run into mounting issues? Like engine brackets and accessory mounting holes? Also what about sensor location issues. I know it's a backward swap most people go from Renix to H.O but considering the conditions of the jeeps it makes more sense to put money into the 90 over the 92. Any thoughts advice or suggestions would be appreciated thanks again!


Sent from my iPhone using WAYALIFE mobile app
 
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