Different years 4.0l replacement.

[Duncan71]

So I'll be posting a build in the build section once I'm done, but basically I've got a CJ front clip YJ that doesn't run, and XJ that's great except body.  About $2000 invested amongst the lot, and I plan to turn three jeeps into one running one.  CJ clip will be easy, but transplanting the 1997 4.0l into the 1992 might be more difficult. The 1992 was originally an inline 6/ax15, as is the XJ motor and trans.  Plan is to use the old intake and exhaust manifold, and swap everything onto the 1997.  Does anyone have any idea of the common issues I might run into?   Any suggestions or ideas?  Are the two years of 4.0l long blocks even compatible?  Thanks for any and all insight. Pics to follow!

[TL-Iguana]

Intake and Exhaust manifolds should have been standard from 84- 00. The blocks should be the same. Same mounts etc. It's the engine management systems that will help determine what works and what doesn't.....

Your 92 is going to be OBD I. The 96 and newer jeeps are OBD II. This will mean your electrical harness is going to be different. You will probably have issues with your MAP sensor currently being located on the firewall, where as the '97 and up sensors were mounted in the throttle body. It more than likely also has a different connector. 96 -'97 were big transition years for Chrysler as they worked on conforming to OBD II standards. The wiring of everything will more than likely cause you the most grief. Transmission controls might also be different, including the connectors...

[BrokenAxle]

Use a painless harness to control the engine.  Then you can put it in whatever you want.
I just happen to have one of said harnesses.  If interested pm me!

[Duncan71]

Well, to avoid purchasing anything more, and because my blown motor is complete, my plan is to completely strip it of all accessories and such, unbolt the intake and exhaust manifolds, and do the same to the 1997 motor. I will then re use the old accessories, intake (throttle body, fuel rail/injectors) and exhaust, thus retaining the OBDI functionality of the 1992. So far the only issue I have heard of is a secondary temp gauge that either needs to be drilled and tapped in, or using a HESCO part. Everything about doing it this way make sense, but as this will be my first attempt at this swap, I wanted to run it past the Jeep gods on this forum.  (also posted this on jeepforum.com)

[xpedition xj-eh!]

I've pretty much done the reverse. I installed a 93 YJ OBD-1 engine into a 99 XJ OBD-2. I wrote about it here:
http://www.naxja.org/forum/showpost.php?p=245794709&postcount=7

You shouldn't have to many issues. The biggest thing being that your older head will need to be drilled and tapped for a temperature sensor (I have a pic in the link above).

[hps4evr]

I did this on my old yj. '98 4.0L into my '92 yj. The only thing I recall was the coolant temp gauge sensor had to be relocated, I drilled and tapped a hole in the thermostat housing, and extended the wiring. Also check the pilot bearing in the crank on the new engine, make sure you have the proper one. Everything else bolted up from what I recall.