engine swap

jakbob

New member
i need to know exactly what i would need to put a 4.0 into an xj that had a 2.5...just trying to get a price quote...
 

I am finishing up a swap with a GM 4.3L V6 into my 2.5L YJ. Replacing the engine, transmission, transfercase, fuel delivery, driveshafts, radiator, ECU, and other random parts has cost me about $1700 and I still don't have all the parts I need to finish. That price is total cost of parts without having sold my old engine and t-case. Swapping a Jeep 4.0L should not cost this much since you should be able to reuse a lot of original parts. I do know that you have to move engine mounts forward to fit the 4.0 in place of a 2.5L. Have you considered using a V6? It is a lot more light weight than in I6 and the GM V6 is supposed to produce around 200 HP and 274 ft. lbs.
 
You'll need a new transmission to bolt it to, as the AX5 that your 4 banger was mated to just won't get it done with a 6 cyl.

Engine problems?

:(
 
not really, but after a weekend in the mountains and having rigs with full loads beat me uphill...i realize i dont have enough power..
 

jakbob said:
not really, but after a weekend in the mountains and having rigs with full loads beat me uphill...i realize i dont have enough power..

You can squeeze more out of the 2.5... do a search and check out that 4bangersunited site.

...and there's always 4 Low.
 
yeah...i might want to like, buy a junker 2.5 and do some mods to it...i dunno...I NEED MORE POWER!!
 
No single mod will make it a hot rod, but lots of little things you can do that combined will make it run pretty strong for what it is.

It's been covered often here, so there should be tons of info if you search for it.
 

ok so i plan to get an i6 and an ax15 but will the chrysler 8.25 i got do the job? or will i need to get a dana 44? also... i know that the engine mounts would have to be moved, could i use the ones from the 4banger? and i heard somewhere that i would have to cut into the firewall...is that true? im trying to figure out how much trouble it is gonna be....
 
also, should i get a new TC? i was reading that the 231 behind a 4banger would be 21 spline and the tc behind a 6 would be 23...just trying to figure this out...lol...


(the only way to learn is to bite off more than you can chew and deal with it)
 
my jeep has the 4.0 I6 w/ the AX-15 and my Chrysler 8.25 is more than enough (even w/ 225k miles!) This is one solid setup, i strongly recommend it!
 

The 8.25 is fine, came stock behind the 4.0L with the tow package.

You'll need to massage the firewall with a BFH to get the 4.0L to clear, as well as modify the front clip forward of the engine. You'll need the 4.0L motor mount perches but they bolt right in.

It's generally more of a headache and $$ to make a 4.0L work, and easier to go custom like the 4.3L Vortec. The 4.3L will fit better.
 
ok...what vehicles came with the 4.3 vortec? cause ill probibly pull it from a junk yard...
 

that 4.3 vortec is common in later model blazers n jimmy's... i know the '97 models came with it at least so i'd imagine anything with that body style would be fine. should be cake to find one. if you call up a parts yard the "4.3 vortec motor" is such a commonly known motor that you wouldn't have to tell them what it comes in, just say you're puttin it in ur jeep.

BFH = big F'in hammer. Swing away.

Front clip is the front end of the car (generally what you replace when you rear-end someone... front bumper, fenders, grille, front cross member, radiator supports, hood, that kinda thing.)
 
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ok ok..so i blew my little 2.5.....dont ask....so i officially need a new (ish) engine preferably a 4.0 MPFI...and a ax15 transmission....maybe a TC if the ax15 doesnt have the spline count of the 1995 np231....really bad time for my jeep to die...
 

well the way i see it...one way involves another 2.5...but the ones i can find are like remanufactured at like 1600 dollars...the other way i can do a crap load of work and get a 4.0, ax15 and maybe another 231 for the same price....but the regearing sounds like a good idea...i dunno...im still trying to figure out what to do...how would i go about regearing?
 
Sell what you have and go out and buy one with the 4.0L already in it. It will Save you a ton of $$ and time.
 

put a vortec in there. $/HP its the best upgrade you can do for yourself here... plus your 2.5 is blown, how perfect.
 
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