90 XJ

I have a 90 jeep cherokee laredo with the 4.0 renix engine in it. It has 202,000 miles on it. Its getting up there and age. I've been trying to sell it for $2500 because I've put alot of parts on there to get it running right. But if it doesn't get sold, I'm considering rebuilding the engine. Motor doesn't have a rod knock, but does have piston slap. OR I'm considering on dropping in a H.O. engine from a low mileage jeep. Mine is automatic. My question is what all would I have to do to have to complete a standard rebuild stock everything? Or what would I do to do the H.O. motor. I'm willing to swap engine wiring harnesses.

too many things to list.

seriously, do a search, i know the HO to renix swap has been covered in detail. if you are going to swap harnesses and ecu/pcm, than everything from the HO needs to be swapped from the doner vehicle.

if you do a rebuild, buy a complete rebuild kit. have the block and head sent out to a machine shop to be cleaned and checked for proper specs.

AMC sixes have gone a couple of hundred thousand miles with "piston slap" without trouble - especially the earlier ones (pre-1990.) AMC built them tough.

A good "basic" rebuild, to me, is:
Hone the cylinders (bore only if necessary. Probably not, in your case.)
Replace rod & main bearings (measure journals to see if undersize bearings were used.)
Re-ring (usually necessary.)
Timing set (you're there anyhow.)
Replace water pump.
Replace oil pump.
Replace valve lifters (cam replacement not necessary for this) and pushrods/rocker arms (after inspection - may not be required.)
Replace rear main seal.

That's all I can think of at the moment. Everything can be done, with care, without removing the engine (you'll have to remove the transmission if you have to actually replace the crankshaft, if you want to do it with engine engine in situ. It's certainly possible.)

How much more you do depends on your innate perfectionism (people have usually done less than listed above and called it a "rebuild," your skills, and your capabilities.

You can swap the short block from the HO in with only needing to drill and tap the boss for the knock sensor, and you wouldn't need to swap wiring to do that. Any more than that, and some work is involved - but it's mostly been covered here before, so I shan't go into detail on it.

Ok, I was considering on replacing all moving parts in the engine, tired of blowby going through the valve cover oil cap, and air box.

Pull motor take to engine rebuilder......... spend extra cash and go with roller motor.

No thanks I would rather do the rebuild myself.

must have a machine shop in your garage???? price saved on assembly is minimal vs time. Prolly the reason I dont assemble my own (unless its going into the stock car)

PornstaR said:

must have a machine shop in your garage???? price saved on assembly is minimal vs time. Prolly the reason I dont assemble my own (unless its going into the stock car)

Click to expand...

I can't say as I blame him - not only do I enjoy doing the work myself (and it gives me a chance to do a final check-out...) but I just can't see myself farming out work I'm perfectly capable of doing - and equipped to do - myself. Thus, I'll farm out the machine work (once I find a shop I trust,) but I'll do the assembly myself.

Change tyres? I'll usually do it at school - the tyre changer is there.

Smog? Brother, I /wish/ I could do those myself! I just can't bring myself to trust those guys...

I'd like to have a machine shop in my garage, but I don't (and probably won't anytime soon. Damn.)

If the man wants to do it himself, power to him! If he has the time, so much the better. If he enjoys the work (I know how that goes,) then he's ahead of the game, since it isn't work to him...

Oh Jon you know I dont doubt your capabilty, nor mine on this subject. Just with this day and age on the net with "can i do this?" questions left and right, it ends up with "my motor blew up cause i donno what im doing". Seen this too much and even more again this year on this site. Already hearing it in another thread right now on a simple cam replacement and no one on site knows what the hell they are doing. I see this in the end requiring "the board" to fess up and give a play by play to build an engine over the net in the end. Maybe my tactic but when pricing my time (I work 14hrs a day @ 35/hr. my time is short and have plenty of money. So it wasnt a question of skill or tools but one of time and need to get the motor done when rebuilding entire jeep..... one less thing "I" had to do)

go for it if you think you can tackle the build, sadly I wont help e build an engine on line tho.

I have a whole haynes manual that tells you what to do in overhauling the engine. Besides it will be on a stand. I'm not definite on whether I want to rebuild or not yet.