4.0L Engine Swap Question

I'm lookin' to replace the engine in my 88 XJ. So, I was wondering what year range of XJ's I can take an engine from without to much hassle? Could I use a HO engine from a 91-01, can I use any from 87-90, or do I need to stick with an engine out of an '88? I don't mind doing some minor mods to make an engine work, but this is my daily driver, so I need to be able to get the old engine out and the new one in as quick and easy as possible.

Any renix engine 87-90 to keep your swap simple and fast.

Other wise you can swap in a H.O. from 91-96 if you had the complete wiring harness, being the engine bay and dash wiring harness. And the the H.O. giving you more base H.P. and a great foundation to build on.

My '87 MJ has 4.0L from a '01 Grand Cherokee mated to a AW4 tranny.

Swap relatively trouble free as the bolts lined up, etc. Ended up using the Renix harnesses and such for the whole job.

Here is more facts since I have done exactly what your wanting to do.

You can swap in up to a 1996 motor without too much work.

After that, you get into a different head for 97-99 and wont have a sensor port for your dash temp gauge.

Here is the recipe.

1995 HO or 96
Use your 1988 intake so you have sensors, fuel, throttle body etc.
Use a 1995 HO exhaust or buy a APN header for $115.
Screw in all sensors and accessorys plus brackets from your 1988 to the 1995 motor.

Use your fly wheel and crank position sensor from your 1988
Use your distributor from your 1988

Take to exhaust shop and have them put up a new down pipe with O2 sensor bung and connect to old exhaust.

Thats IT.

All wiring is the same at that point so no need to switch harnesses. Your basically just replacing the long block which are nearly identical. the HO head has raised intake ports which your old intake will bolt right up to without any issues at all.

Make sure you use a HO intake/exhaust gasket for the 1995. Use spark plugs for the 1995 motor as there was a change in depth along the way.
Cap off your EGR junk too, you don't need it.

Thanks for the help guys! Any suggestions on a mileage limit I should look for in a replacement engine to help make sure I'm getting a good one? My XJ has 335,000 miles on it, but I don't know if it's still the original engine. I just don't want to end up swapping one worn out engine for another worn out one.

Bouncy, is the new exaust down pipe needed if my down pipe already has an O2 sensor, or is the sensor for a HO engine different?

The down pipe is needed.

The HO head has mis-aligned ports compared the the non-ho head. non has ports straight across, HO has them about a half inch higher on the intakes.

The intake bolts up but the EGR pipe wont. The exhaust manifold sucks on the non-ho compared to HO.

When you put the HO manifold on, it doesn't have an egr port, it also has a different location for the flange mounting to the down pipe. Thus, you need a new down pipe.

My local shop charged me $25 to bend a 2ft section of down pipe with bung and welded it in for me to the exsisting exhaust pipe. Bolted it to the new HO manifold.

As for engine age. Get one below 100k. Mine was replaced at 213k. I put in a 95 for about 5k miles while I built a stroker out of the 90 block. Then swapped out the 95 and sold it for what I bought it for.

Now I have a 90 block, 95 head, apn header, 99 intake...you get the idea...Mixed up puppy that runs like a raped date