89 to 87 4.0 swap

i've got 2 xj's now. one is an 87 and has 175k miles and needs at least a head gasket, possibly more work. the other is an 89 with a remanufactured jasper 4.0 with 60k miles and a remanufactured aw4 with 61k miles on it. the 89 has a smashed unibody and a major rust problem (as in i couldn't find a place to use my floor jack on the driver's side 'frame'), so i'm switching the engine and tranny over, possibly the t-case also. both came with a 4.0 and an aw4. my question is, what issues might i run into with this? i'm aware that the 4.0 was introduced in 87, and they made some changes to it for 88. for example, some of the wiring is ran slightly differant. has anyone done a similiar swap? my goal is to do this right the first time with as little headache as possible.

Should be no issue. The RENIX control system (that's what you've got) was used 1987-1990, and they "revised" a few things for the 1989 model year (thus, two RENIX "generations," 1987-1988 and 1989-1990,) but the block and head castings and ancillary parts didn't change. Even used the same sensors.

How shot is the 87? I've got a project I'm working on (RENIX Decoded) that I could always use donor parts for - I've got to set a RENIX system up, outside the vehicle, as a simulator that I can play with. I'd like to talk to you about parts out of that 1987, if you don't mind...

5-90

That's what i tought, but never hurts to check before doing major work

as far as the 87 4.0, i'm not really sure yet. it's still in that jeep right now. it doesn't have major knocks or ticks that i've noticed, has the typical oil leaks, but overall seems to be pretty solid. it has 175k miles, and i'm considering parting out the 87 engine and tranny. in fact, i'm going to be parting out whatever i don't use from the 89, so basically i'll have 2 full renix xj's for grabs. only thing is you'd have to pay for shipping from michigan.

dave

opps, make that 1 full renix xj up for grabs, not 2.

You may notice the 89's EGR system contains a transducer which the 87 does not. No big deal. Model numbers for the ECUs should be different too, but should still run everything.