[AZ Jeff]

My 1989 MJ has a 4.0 out of a 2000XJ, and has developed some SERIOUS piston slap. It has a new head and valve train, and new rod and main bearings. None of the piston skirts are cracked....yet. But the noise is pointing to some wonky pistons, and my borescope is showing images of said same.

So I am looking for a REPUTABLE source for a reman 4.0 short block for a 2000 or later XJ/TJ.

I saw one outfit on eBay called the "Jeep Parts Depot" in Sun Valley, CA. Does anyone know anything about them? Or can any one offer any other suggestions or a source?

 

[Digger84]

any old style 4.0 short block will work (new style won't work as they have different hole location for motor mount attachment

you want a 4.0 short block for a 91-2001 XJ or 93-98 ZJ or 91-96 YJ or 97-99 TJ

what won't work is from a 99-04 WJ or a 2000-06 TJ as they are all new style 4.0 block

 

[Digger84]

if you used the head from a 2000 XJ do yourself a favor and get a tupy head from a 02-04WJ or a 02-06 TJ but if you did not use the crack prone 2000 XJ head don't worry about it

 

[AZ Jeff]

if you used the head from a 2000 XJ do yourself a favor and get a tupy head from a 02-04WJ or a 02-06 TJ but if you did not use the crack prone 2000 XJ head don't worry about it

I have a new cylinder head from Clearwater Cylinder Head that is the TUPY style. My original "0331" head had a crack from an overheating episode prior to me owning my MJ.😟

 

[cruiser54]

Jeff, some clarification for me as I finish my first cup of coffee this morning.
Which block is currently in your MJ? The one with original accessory mounts or the later style?
As far as suppliers go, they're all a crap shoot.
I would source a good used short block and have a local machine shop build it.
There's a machine shop here in Prescott that is good and he may have a core short block to build. Pete

 

[AZ Jeff]

Jeff, some clarification for me as I finish my first cup of coffee this morning.
Which block is currently in your MJ? The one with original accessory mounts or the later style?
As far as suppliers go, they're all a crap shoot.
I would source a good used short block and have a local machine shop build it.
There's a machine shop here in Prescott that is good and he may have a core short block to build. Pete

Let's take this back channel on the Comanche Club forums.