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90 4.2L in 93 XJ

Jeep Ritter

NAXJA Forum User
Location
BelAir, MD
Scored an XJ for free but it is in need of a motor, not wanting to sacrifice the engine from my current project, although it won't be ready for sometime I wanted something to wheel for now. Before I head out to the local yards I was offered a running 80,000 mile 4.2L from a 1990 YJ for free and was curious to see if anyone knew just how much work it would be to drop it in the old XJ.

Of course I would be fuel injecting it but due to the fact that I have a complete 4.0 at my hands and that it is from the same engine family I figure it can be pretty easily done. Or is this more work than i anticipate?

I'm sure someone has done this before and since I haven't, any advice is welcome. Thanks in advance

Some specs that may be needed - 93 2dr XJ, 4.0L/AW4/NP231, D30/8.25
 
Well, the engine itself will bolt right in. You'll have less power than a stock 4.0, and you'll have to modify the intake/exhaust manifolds slightly to make them fit the 4.2's head, the ports are not in the same location as the xj head.

What I would do is take that 4.2 so you have a crank for a stroker 4.0 to build. If this is a "I need an engine right now" kinda thing, throw it in, but go get yourself a 4.0 HO head first. This will give you the added benefit of the raised runners for the intake which will help get some power back.

A friend of mine runs a 4.0 head on his carbe'd 4.2L CJ, and it made a huge difference in power. He's doing an EFI swap later this year.
 
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