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4 cyl swap

gump

NAXJA Forum User
Location
two harbors, mn
Ok, I need a little help from the gurus here. I have a 84 xj, equipped with a carbureted 4 cyl, 4 spd trans, and I believe the 207 t-case sitting in the yard with a blown engine. I was recently offered a fuel-injected 4 cyl, mated to an ax-15 and whatever t-case was attached to that from a mid 80's wrangler. Will this powertrain bolt into the XJ with minimal modification? I know the fuel injection will have to be wired up, but what about drive shafts, motor mounts, trans crossmember and such? Any help would be great!
 
Same engine, physically. Mounts and all should match up just fine. Mid 80's must mean throttle-body injection, which is Renix-based. Wiring should be easy if you have the ECU,
 
The Wrangler has a different shifter linkage style. I put a TJ tranny/t-case into my 88 MJ and had to invent a custom linkage using parts from both the TJ and my 86 MJ (the 88 used to be 2wd). I used a simple steel bar bolted to the tranny to support the other end of the linkage bar (the one that rotates). I know it's hard to see, but this is what I did:
22091458.jpg


The t-case of the Wranglers is rotated up higher than the XJ/MJ and gets closer to the floorboards. Not sure if this matters at all with a stock crossmember. I have a custom one that raises everything up a bit.
22358720.jpg

I haven't a clue about the tranny mount because of the custom crossmember and mine was from a '00 and don't know if it would be the same as the mid 80s.
Oh, and the tranny on that wrangler should be an AX-5, not AX-15.
Take lots of pictures and share your project with others! :D
Jeep on!
--Pete
 
I'm about 99% sure it doesn't have an AX-15. Not sure on what it has but it won't be an AX-15. I did a carb'd 2.5L to a throttle body injected 2.5L in an 85. You will need all the emissions stuff and will need a tank and fuel pump from a later model XJ for the electric fuel pump. It makes a significant difference in performance. You can't simply bolt it to your tranny since you need the CPS configuration. There is an aftermarket CPS relocation kit for the 4.0L but it won't work with the 2.5L.

I got tired of fighting mountain passes with the 2.5L and have since gone to a 4.7L stroker.
 
When I was considering a FI for my 2.5, I was told by the guys at Hesco that they could custom cut the harmonic balancer and supply a mount kit for the CPS relocation. I just went with a carb...seemed like a good idea at the time.

Another possibility is to use the ignition and induction systems from the old engine...it won't run nearly as well as a FI, but the cost will be cheap..gaskets and maybe an electric fuel pump (your replacement engine may not be machined to accept a mechanical pump).
 
Thanks guys, I'm thinking I'll just get rid of the 84, and keep working on my current 86 money pit. Like I need another project, right? The 86 is runninig the dreaded 2.8, and I'm thinking I'll just swap in an injected 2.8 out of like an s-10.
 
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