My jeep is an '89 Renix era XJ. I recently spun a bearing in the lower end and yes i know it isnt too much of a hassle to fix but i used it as an excuse to address some knocking i had going on. My engine is all apart ready for a new lower end. I have a complete 97 motor that i plan on using just the complete block to swap out bottom ends. All i'm asking is if my renix head will go right on the newer block, and if there are any sensors i should swap or make sure to check when swapping blocks. thanks

 

both 4.0's

 

You can use the new head too. There are some flow differences but unless you're building high performance engines it doesn't matter.

There are two differences you should be aware of:
1. The 1997 block does not have a tapped boss ready for the knock sensor. It's cast but there are no threads. You'll need to tap it if you want that sensor to work.
2. The 1997 head does not have a fitting for the temperature sending unit. You'll need to drill & tap into a coolant passage somewhere, either at the thermostat housing or in the historical location.

ALL sensors need to be swapped. The Renix and Chrysler OBD-II fuel systems have significant differences. Always use the sensors and accessories that match your ECU/PCM. The alternators are also incompatible.

 

What he said^^, and this:

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

 

I mean besides the knock sensor and distributor wouldn't it be easier to use the lower end and throw the RENIX head on and call it a day? The head off the 97 is questionable but the block is clean. The RENIX head I have is in great shape I'd rather use it.

 

Sure. That would be great.

 

What about my RENIX oil filter the plug on mine and the plug on the 97 engine are different.

 

Use all sensors and accessories from the Renix.

You'll need to stick with the '97s oil filter though. The oil filter adapter is SAE threaded instead of Metric.

 

Are you sure I can't use flywheel?

 

YES. Positive. Use all the Renix stuff.

 

Did any of you guys have issues with the pilot bearing when doing the swap? My buddy had to pretty much fab his own to get it to fit

 

Got mostly everything swapped over except flywheel. any tips tricks on getting those tight *** bolts out with the engine out? I tried putting another wrench on the front hb bolt and I didnt break any flywheel bolts loose just the hb bolt.

 

I simply used an impact wrench. Just don't hammer down on it though, short little bursts should be enough to break them free

 

Broke the plastic end to the hose in the middle of the picture. The metal fitting all the hoses go to isn't in a parts store is it? I don't know how I'm gonna fix it

 

That's the heater/coolant control valve. It is an unnecessary piece of crap to have on your Jeep and is prone to failure. Chuck it. Plug the vacuum line going to it and splice the 2 hoses together.