2.8 to 4.0 swap

[rainmakr95]

Hi everyone!

My 86 mj has developed a rod knock. I don't know which I should do. rebuild the 2.8 or install a 4.0 How much headache would it be to swap over. From what I've researched, the 2.8 is a Chevy block. Can Anyone give me some help.

If anyone in New Jersey or nearby Pa. has a 2.8 let me know Thanks

Bob Hartman

[Pete M]

It's quite an involved swap. Essentially, you'll need to gut your entire truck and swap in everything from a donor MJ/XJ including the entire wire harness, dash,, radiator mounts and hood. A more straightforward swap is to get a 3.4L chevy block from a Camaro/Firebird. It's a near bolt-in procedure. :thumbsup:

http://jeep.off-road.com/jeep/article/a ... ?id=277008

[dasbulliwagen]

The 3.4 will take all of your 2.8 accessories, manifolds etc, just bolt in, but I think you may have to have your 2.8 flywheel nuetrally balanced by a machine shop, as the 2.8 used it for balance, but the 3.4 doesnt. Do some research on this though, I'm pretty sure thats right. car-part.com should be able to locate an engine for you used. Good luck and keep us updated!

[rainmakr95]

I didn't mention that I have an automatic trans. I assume it's a 904 that came with this truck. That being the case, will the flex plate bolt up or do I need a different one?

Bob Hartman

[dasbulliwagen]

The flexplate will bolt up, but like the flywheel, you will need to have it nuetrally balanced by a machine shop.

[Tri_X_Troll]

What about just using the flywheel off of the donor engine?