piston replacement on Jeep 4.0

[artificialist]

Originally Posted By: OVERKILL
I thought these engines were "unkillable"

Failing piston skirts don't strike me as the mark of an "invincible" engine.

It seems like certain years of the engine were extremely tough, but only certain years were prone to piston skirt failure or cylinder head cracking.

 

[Virtuoso]

I'm with the "replace the broken piston but mic the others and check for bore damage" crowd.. especially on a winter beater.

 

[Donald]

Originally Posted By: OVERKILL
I thought these engines were "unkillable"

Failing piston skirts don't strike me as the mark of an "invincible" engine.


The basic block is unkillable. Its when you add pistons and a head you have problems.

 

[OVERKILL]

Originally Posted By: Donald
Originally Posted By: OVERKILL
I thought these engines were "unkillable"

Failing piston skirts don't strike me as the mark of an "invincible" engine.


The basic block is unkillable. Its when you add pistons and a head you have problems.


LMAO!!! Well played sir

 

[stephen9666]

Well, while bored last night I was googling parts for the OP's vehicle on Rock Auto and Northern Auto Parts.

Just my casual observation,

If you decide to go beyond replacing a single piston, your best bargain will be buying a rebuild kit with standard (not oversized parts), since you'll then be getting all the gaskets/rings/bearings in one fell swoop.

Of course, you probably would have figured that out anyway.

 

[Thax]

Another option I think nobody else mentioned was a new short block. The cost of a short block for this motor is not high (compared to other engines). Assuming the head and the external engine parts are good ,just swap them to the new block. I think this is a better option than a used engine and easier than tearing down the block and certainly more effective than replacing just one piston.

 

[zrxkawboy]

It's been a crazy summer, and I just got the head pulled off. Cyl 6 actually looks good - no damage - with just a slight ridge at the top, though the piston popped out easily. So I wouldn't be a total idiot to just hone the cyls and put in a new set of std pistons? Does anyone know if the new aftermarket pistons have an improved design that is less prone to cracking? Thanks again.

 

[jeepman3071]

Originally Posted By: zrxkawboy
It's been a crazy summer, and I just got the head pulled off. Cyl 6 actually looks good - no damage - with just a slight ridge at the top, though the piston popped out easily. So I wouldn't be a total idiot to just hone the cyls and put in a new set of std pistons? Does anyone know if the new aftermarket pistons have an improved design that is less prone to cracking? Thanks again.


I'd say honing the cylinders and putting in a new set of pistons will keep you going for a long time.

I've heard that sealed power pistons are good, a lot of the guys on the jeepstrokers.com forum like the Keith Black forged pistons from summit racing. They are more money but well worth it.