Hey guys!

Just got a 1990 Cherokee with the 4.0L with 273k for $800. I bought it knowing that it had an engine knock. Looks like I have diagnosed it as a loose connecting rod in the crackshaft. I checked the rods and lifters they are tight and have no sounds coming from them, so when I dropped the oil pan, the rod bearings were a little loose and space between them and the main bearings on the crankshaft. I also know that it is not torque converter bolts. Here's a video to show what I'm talking about (sorry for the bad quality):



My question to you guys is this: I found a crankshaft kit online (AutoZone first, but I've found it a number of other places as well). Here is a link:

http://www.autozone.com/autozone/par...7825_124715_0_

Do you think I should go with that, or just swap in a new engine? I know a place that has a couple running ones for $500.

 

I personally would opt for a swap with a compatible 91 up. Design improvements make it worth while. Read the other threads to avoid those little gochas that go with it.

 

Here's how to put a later model engine (HO) into your 90:

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
　

 

Are the cylinder walls in good shape? Sounds like it's time for a 4.2L crank and rods and make yourself a stroker

Or just follow cruiser54's writeup.... I guess...

 

To be honest the cylinder walls look okay (not excellent...just okay). That's why I am debating whether I really need to do the swap or if the crankshaft kit will be enough...

 

i'd stroke it.