Hi

Hi, I'm kinda new here, I mean to this section of the jeep world. I just bought a 1985 XJ with the 2.5L in it and I had a couple of questions. I read somewhere that it would take MAJOR work to fit a 4.0L in the 84 - 86 XJs, is this true? Also do I have a ax-5?



Thanks for the help,
SouSy

1. Welcome!!!

2. The 4.0 will fit, but you'll need
a. the 'front clip' (radiator 'core support' panel) from an '87+;
b. all the FI electronics from the donor vehicle of the 4.0; and'
c. hafta beat on the firewall a few places with a BFH.

3. Do a 'search' of this board, lots of threads about this issue.

-Rick

2.5l

I'm sure that Ghost is gonna jump me but here is my $.02 worth.
The 2.5l can be made to wheel and drive quite well. Plan on a cam, bore, haders and you'll have to upgrade the carb to a Holley or refit it with a later model tbi. If you want to put in a 4.0 and have the time and resources then go for it. You will have to swap out the front end and bang up the firewall. Its a great project. If you have less time/resources then buy an XJ with the 4.0l and start from there.
You do have the AX-5 which does not bolt up to the 4.0l and requires about $1000 of adapting, money better spent on the rest of your rig.
I guess if you already have a donor engine & tranny then its a good economical swap. If not then it requires either a lot of money or a lot of time in the junkyard scrounging parts. Either way is mucho fun.

Re: 2.5l

HossHoffer said:

I'm sure that Ghost is gonna jump me but here is my $.02 worth.
The 2.5l can be made to wheel and drive quite well. Plan on a cam, bore, haders and you'll have to upgrade the carb to a Holley or refit it with a later model tbi. If you want to put in a 4.0 and have the time and resources then go for it. You will have to swap out the front end and bang up the firewall. Its a great project. If you have less time/resources then buy an XJ with the 4.0l and start from there.
You do have the AX-5 which does not bolt up to the 4.0l and requires about $1000 of adapting, money better spent on the rest of your rig.
I guess if you already have a donor engine & tranny then its a good economical swap. If not then it requires either a lot of money or a lot of time in the junkyard scrounging parts. Either way is mucho fun.

Click to expand...

I know the 2.5L is a good motor, but it has 201,000 miles on it, and the wiring is horrible, so I figured I would need to swap out a new engine anyway why not put a 4.0L in while im at it.
I knew that the ax-5 would not bolt up to the 4.0L, I was just asking to make sure. Thanks guys.

I still have a pic of a 350 Chevy SB sitting under the hood of a 1992 XJ on my toolbox at work. It looks like it belongs there. It was dropped in (1994) using custom motor mounts and a custom adapter for the TH-400. The exhaust note confuses the hell out of people.

SouSy --

The 2.5L engine shares a bell housing bolt pattern with the GM 2.8L engine that Jeep also offered in the XJ from '84 through '86. The 2.8L is a POS, but the GM 3.4L crate engine (also used in early 90's Camaros and Firebirds) is the same block and is as good as the 2.8L was bad. I have a preference for the inline 4-banger, but if your 2.5L is at the end of the road, swapping in a 3.4L would be a whole lot easier than either a 4.0L or a 350 V-8 (which is a real shoehorn job, and will always have cooling issues).