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Question about 4.0 internals

pizzaschmidt

NAXJA Forum User
Location
California
Hey all. It finally happened... Ran the Jeep through a deep water crossing and hydro-locked the motor, snapping two of the rods right in half. The rest of the engine is in good shape and being a broke college kid, I decided to just replace the two pistons+rods, replace the essentials, and slap the motor back together. My question is whether or not the pistons+rods from a 2000 TJ would work in my 91 XJ. I know there were block differences between these motors, but if the internal stroke and bore lengths are the same, I should be able to swap them in no? Also, if there are differences what Jeeps do have compatible internals with the 91? Any help is appreciated, Thanks!
 
Seems easier and quicker to just grab another cheap 4.0 and swap it. Why bother tearing it apart? Who's to say everything else is fine after drinking water?
 
You'd have to swap on your whirley bob in place of the cam stator, for one. Use your intake manifold and everything attached to it. Exhaust ports are going to be different so you will have issues with exhaust manifold gaskets lasting a year. And you will have to make/buy adapters to make the accessories work and to get the engine to physically mount in the jeep.

Plus a 2000TJ is going to have the 0331 head and be more prone to cracking.
 
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