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swapping motors, got some pretty odd ?'s

thechief86

NAXJA Forum User
Location
White House, TN
so, i dunked my jeep, and after 2 weeks couldn't ever get it to run right again, so next week i'm swapping the motor. i've swapped a 4.0 HO into a renix jeep before, so i know what that entails, but this time, i'll be swapping in a franken-motor that is comprised of a 4.2 block with a 4.0 head on it. i know the motor runs fine, and i've known of some cj and fsj guys doing that mod to their jeeps. the 4.2 is the 4 weight model from a yj, and i think the head is from a renix motor. it was recently put together, had good compression, and all the seals were replaced. my questions are these:
are there holes on the 4.2 block for my a/c, alternator, and power steering pump brackets? will my 4.0 water pump fit so i can run the factory dual fan setup, and the serpentine belt? i'm just tryin to get my jeep goin again, because this is by far the nicest xj i've ever had, and i've been having to dd a motorcycle in the icy coldness for the past couple weeks, and i'm not sure my nuts can shrink much more without imploding:
:scared:
puke.gif

thanks ahead, fellas!
~eric.
 
Not many people swap 4.2s into XJs so I'm sure there won't be many able to chime in on this.

Why not find a running renix 4.0 for cheap and not worry about the hassle?
 
well, cheap, free, and convenient were all characteristics of this motor, because it's already out of the xj it was in a couple weeks ago, and this one has been rebuilt, but the 258 block needed less machine work than the 4.0 block, so that's what he went with then. he sold the jeep without the motor, and now he's doing me a large favor by offering up this motor. when he had it in his xj, though, i think he never got the project far enough to try to put the xj stuff on it, but did get the motor to run without accesories, and it ran good, with about 130 psi compression on each cylinder.
i posted on the FSJ forum as well, because a lot of those guys have 258's that they have swapped our FI heads onto.
 
my questions are these:
are there holes on the 4.2 block for my a/c, alternator, and power steering pump brackets? will my 4.0 water pump fit so i can run the factory dual fan setup, and the serpentine belt? i'm just tryin to get my jeep goin again, because this is by far the nicest xj i've ever had, and i've been having to dd a motorcycle in the icy coldness for the past couple weeks, and i'm not sure my nuts can shrink much more without imploding:
:scared:
puke.gif

thanks ahead, fellas!
~eric.

The block will be the same.
 
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