1991xjcowboy

I recently purchased a 1991 xj in rough shape the body is heavily rusted and the engine is knocking I have found an 89 renix engine that I wanna put in using my h.o. head I need as much info as I can get on how to do this swap

bubbarules1958

Use the flywheel, distributor and intake from the HO. I did this swap. I also recommend changing the oil filter housing as they're different threads. Use the search^. It will get to some information.

1991xjcowboy

I've tried searching it and all the info I keep finding is going the other way from renix to h.o. And I'm wanting to go to renix because it has been rebuilt and has better power than my wore out high output 4.0

bubbarules1958

first couple of pages should help you out. If u have any questions feel free to ask. https://www.cherokeeforum.com/f2/90-...y-91-a-181505/

cruiser54

Here's how to do it from Renix to HO. Just use it as a guideline for what needs to be changed over. Be sure to use your 91 intake/exhaust manifold gasket.

Cruiser’s HO into Renix Swap

This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.

The HO and Renix have some differences but none that can’t be overcome very easily.

Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender.

You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical.
You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.

The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16” square drive or a modified 3/8” drive that has been ground down to fit. Do this before installing the engine.

As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.


Revised 03/28/13

1991xjcowboy

Thanks guys I really appreciate the help