2.5 rebuild - piston questions

[Landon427]

I'm rebuilding my 2.5L (1999 SE, 240k miles). It had a knock that wasn't fixed by changing rod bearings and lifters. Here are two pictures showing passenger side piston scoring and lateral (front to back) piston clearance, which is huge (> 1/32"). I'm hoping this is the source of my problem? The knock was around cylinder 3 as best we could tell using a mechanic's stethoscope. It wasn't there on cold startup and gradually got louder as the engine heated up.

 

[macleanflood]

If your pistons look like that then what do the cylinders look like?

DeXJs on YouTube has some excellent videos on the 4.0s and while not totally applicable, an engine is an engine.

I'm guessing you've got some significant scoring on your cylinders? A machine shop is going to have to see if that can be bored out and if there are pistons available for that size.

-Mac

 

[Landon427]

Thanks Mac - I'll see what the machine shop says.

 

[ColoJeep]

If your pistons look like that then what do the cylinders look like?

DeXJs on YouTube has some excellent videos on the 4.0s and while not totally applicable, an engine is an engine.

I'm guessing you've got some significant scoring on your cylinders? A machine shop is going to have to see if that can be bored out and if there are pistons available for that size.

-Mac

For some reason 2.5 have issues with skirt clearance/broken skirts. I wonder if forged pistons are available ?

 

[macleanflood]

For some reason 2.5 have issues with skirt clearance/broken skirts. I wonder if forged pistons are available ?

Absolutely. They come in/with LS, Hemi and 5.2/9 blocks. =)

-Mac

 

[ColoJeep]

Absolutely. They come in/with LS, Hemi and 5.2/9 blocks. =)

-Mac

The ones I own came in Mark IV flavor !

 

[Landon427]

The machine shop owner explained that a lot of pistons are recessed on the non thrust areas. Newby mistake on my part, to be concerned about it.