I have searched the interweb far and wide and cannot seem to get a straight answer. Im wanting to swap my POS non-running 2.8 v6 for a 4.0. I have heard that it cant be done, that it can be done with extensive firewall mods, that it can be done with just moving the radiator forward and changing the hood. I'd just love to know what the truth is. My xj is a 1985 and I bought a donor 1990, so I have everything I should need. I know some people will say to do the 3.4 swap, but I am dead set on the 4.0.

 

it might be easier to just fix the 90 if it needs fixin and make 1 badass xj outa 2

 

^^ agree.

better off with fixing 90 than doing so much to the 85.

 

you should read this

http://www.jpmagazine.com/techarticl...mmins_4bt.html

 

Well Ive thought about that too. But my 90 is very incomplete. basically the only useable parts are the motor, tranny, and tcase. my 85 is totally complete but the motor is shot. Im not worried about how hard of a job or how long it will take bc I have all winter, I just want to know for sure if it is possible, mainly without messin with the fire wall. The best info I have found is that I only need to change the front clip to move the rad forward to make room. But at the same time I have found contradictory info too. Id love to hear from someone who has done it or even attempted the swap.

 

Where do you live? off topic

 

Southern WV. WV, KY, OH, tri-state area to be more specific.

 

oh ok. B/c there is a guy I know that just recently was talking about this and was wondering it you were him. But nevermind.

 

Yes it can be done without cutting the firewall! You'll just need a nose off a 4.0 equipped xj. Simply because it's easier than cutting out your mounts and fabbing one in. I'm doing the same swap simply because I was givin an engine/tranny/t-case with out the jeep. But in my case I'm installing a 2000 front clip

 

firewall should be the same no matter what motor it has you might need to change the location of the motor mounts ,use the wireing harness from the 90 the tcase cross member may move other then that it should swap without anything being done to the firewall

 

Ooops I was talking about the radiator btw

 

Thats what I needed right there! When I get this under way, I am gonna have a build thread on every jeep forum I can find just for anyone that has questions like me.

 

Just happy to help ya man! Ya I'll have my build thread on here as well soon

 

but ur guna have to switch out the PCM, fuel injector harness,...in fact, pretty much the whole engine wiring system. seems like it would be a real pain in the @$$ to me

 

Oh and you are completely right but it's mucho easier starting with no wiring at all