CJ Motor in a TJ

[njtech]

Will a 258 motor from a 80s CJ drop in 87 TJ? Are
there any differences other then carb-emission setup?

I am looking to take a CJ motor put my manifolds on it
and drop it in.. provided the blocks are the same

 

[jps4jeep]

kinda pointless swap unless the 87 YJ motor is dead. Also, most states, if registering, it is illegal to put an older motor into a newer vehicle.

Other than that, they are pretty much the same motors.

 

[njtech]

Yes the motor is dead of course! . Looking to replace on the cheap..

I would still bolt on all my emission stuff from the old motor
but wanted to know if the cam, compression ratio etc
are the same so it runs correctly with the newer manifolds
and carter carb. So the question is .. Is it the same
long block and internal components.

Thanks

 

[jps4jeep]

for short cash I would look to putting in a efi motor like a 4.0 from a newer jeep or a 4.3 or 3.8 from a chevy.

 

[Keith__C]

you will be able to do the sap as long as the crank snouts are the same. the later model 4.2's have a shorter crank snout than the earlier ones. When I had my Cherokee I was debating a 4.6 stroker motor (4.2 crank and rods in a 4.0) and was trying to locate a crank. if I remember correct the 90/91 years are the short snouts but it is something you would want to check out first, other than the crank snout everything will be a straight bolt in.

 

[MNTrailboss]

I agree with jps4jeep. A cheap 4.0 from the salvage yard will work best. All the parts will just bolt in.

 

[Boze]

You might even be able to trade the 258 and a little cash for a decent 4.0. Especially if you only need the short block. There are always engines at the junk yard that someone overheated and warped the heads on. If your topend is good, you could just drop it on one of those.

 

[Bounty__Hunter]

'87 is a YJ and both motors are the 258 (4.2L).

 

[njtech]

Yes thanks but are there differences in the cam and compression
ratio (if so only certain early ones?) that would cause issues if I used my YJ intake and exhaust manifolds carb etc. That's whats bugging me the most.