Chipped/melted piston

[kro10000]

So we were pulling apart the 4.7L stroker from my brothers TJ and found this in one of the cylinders, a chunk is missing from one of the pistons and there are no marks on the wall from it :???:

 

 

Besides random detonation in just one cylinder I can't imagine how this could happen

[jimoshel]

If your tearing the engine apart then replace the piston. If you just want a cheap, quick fix, polish the rough edges off the missing chip. While your at it polish the rough, pitted edge at the 2-3 O'Clock position. Rough edges get hot leading to detonation. Also gives carbon a place to build up. If I were doing it, I would replace the piston.

[kro10000]

We plan on replacing the piston, I'm just trying to figure out how this could happen to a 35,000 mile motor

[Eagle]

We plan on replacing the piston, I'm just trying to figure out how this could happen to a 35,000 mile motor

Is he running platinum tip spark plugs? The tips can come off, and when they do they tend to break things inside the engine -- like pistons.

 

I won't run platinum plugs. I use only standard NGKs, and they run fine in all my Jeeps.

[kro10000]

No he was running Champion copper plugs, the same type (albiet cooler heat range) that I run in my jeep, and he has run in his for years.

[Eagle]

Tell me he didn't buy the stroker engine from Clifford Performance ...

[kro10000]

Erm no..... It was a titan, he bought it before there was much knowledge on the forums of Titan... Not really sure how they compare to Clifford, though Titan now does have a pretty poor reputation