4.0 and 4.2 block differences

Wes M-O

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Joined
May 19, 2020
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Lisbon
Hey Guys,

Wondering if anyone has any info on the differences between the 4.0 and 4.2 engine block?

Basically the scenario is this, my 1992 4.0 needs a new block, and as the models weren't ever released here in Portugal until much later, parts are like rocking horse shit and shipping in engine prices are childish.

But randomly found a block for sale from a 1988 4.2 that would be perfect if it was a straight swap, but I'm guessing that's not the case?

Steer clear or worth a punt? Any help or advice would be massively appreciated.

Cheers,
Wes
 
Hey Guys,

Wondering if anyone has any info on the differences between the 4.0 and 4.2 engine block?

Basically the scenario is this, my 1992 4.0 needs a new block, and as the models weren't ever released here in Portugal until much later, parts are like rocking horse shit and shipping in engine prices are childish.

But randomly found a block for sale from a 1988 4.2 that would be perfect if it was a straight swap, but I'm guessing that's not the case?

Steer clear or worth a punt? Any help or advice would be massively appreciated.

Cheers,
Wes
They should bolt in place if each other as far as mounting in the Jeep but to use fuel injection, you’d have to put your 4.0 cylinder head on the 4.2 block. There are lots of write ups for doing that but it is not as simple as just swapping in a 4.2 block and bolting all your stuff to it. Read up on the 4.0 head swap for 4.2’s, it might be worth learning about and doing since your options are slim pickins.
 
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