Engine swap - which will work?
 

Greetings, I have a 1996 Cherokee Classic with the 4.0L H.O. and use it as an emergency vehicle and for towing an 18' boat. Recently, I have begun to hear low-end knock at idle and a rattle type noise on wind-down from a mid rev. I have been told that it is either a wrist pin or a rod bearing and that I should just add a can of STP and run it until it dies. However, being an E.V. I cannot do that - what would happen if it decied to die in the middle of a rescue call? - Not!

Either way, I am going to replace the engine rather that try to fix it and need to know which year engine will work without further modifications.

I have heard that the 1998 engine is the best but make sure that I get the intake and throttle body as they are diferent and add H.P. and performance and do not require any mods - is this true?

Next, I have just started to hear what I suspect to be a minor exhaust leak from the manifold and am considering a header for increased performance and mileage - any suggestings?

Please remember, I am a volunteer and therefore these repairs are out of my pocket. I am also recovering from being run over by a truck and trailer while directing traffic at another accident in February of 2010 and having both my legs broken and multiple reconstructive surgeries - so the dollars are short if you know what I mean?
:help:

First, thank you for your services!!! APN header or find a stock replacement, but stock manifold always crack. I believe that the better intake was 99-01 and looks like this:
http://t3.gstatic.com/images?q=tbn:A...kuVMy41-WSZtuC
I needed to modify the APN header to work with a 00 intake, now biggy just a torch and BFH. Search car-part.com for junk yards around you for good low mileage motors. Almost any year is swappable (91-99) and you just keep your accessories. Your current motor will probably run for another 50k but you do beat on it pretty hard so might be a good idea for a swap

:cheers:

It it's an automatic trans, check the 4 torque converter to flexplate bolts to see if they're loose before condemning this engine.

If they are, remove one at a time, add LocTite to the threads, and reinstall.

And also check the flex plate itself. It can crack where it bolts to the crank and it sounds just like a rod knock.

I was going to buy a 2000 that was supposed to have a bad engine. I saw and heard it but passed it up for other reasons. I told owner about flex plate issues. He checked it out ( it was the flex plate he replaced it) and is now still driving it