Looks like what happened first is the 'ring land' on that piston failed in the 'ragged' top area where you can see the ring below.
Then the loose piece of aluminum from the ring land chewed up the cylinder head quench flats,
and then broke the ring land on the opposite side with the 'clean' edge.

The ring land on the 5.7 was made thinner to decrease "crevice volume"
and the area above the ring land got a special a special coating to give it more
heat resistance.



details
http://www.popularhotrodding.com/tec...emi/index.html

This making the ring land thinner is a long continuing trend,
as the ring land on the 5.2/5.9 Magnum was made thinner than the LA series 273/318/360
and the ring land on the 4.7 was made thinner than the Magnums,
and the 5.7 ring land made even thinner than the 4.7/3.7

Better quality aluminum alloys are supposed to allow a thinner ring land to be tough enough to stand even tougher duty.

Why did this ring land break?

Could be a manufacturing defect in either piston shape or the consistency of the aluminum alloys mixture.

Could be due to poor quality oil that 'coked' in the groove of that top ring
which jams the ring with carbon deposits
and prevents both ring and piston from getting
the cooling effect of the lubricating oil.

Could be due to detonation,
either mild pinging over weeks/months of time
or a really bad instance over in a thousandth of a second.

Detonation can be made worse by
partially clogged injectors,
very hot dry summer air,
or oil leaking in that cylinder past the intake valve stem seal which may have failed,
or excessive ethanol in the gasoline blend that leans the a/f of that cylinder out too much at wide open throttle.

There have been some recent posts that SuperChips reprogramming does away with the ignition timing corrections for high air temperatures and high coolant temperatures - and this is on top of intentionally leaning out the WOT air/fuel ratio to gain some horsepower.

Was a SuperChips/Hypertech being used?

 

Many possibilities. Now where is the details. Didn't mercedes do something like this not too many years ago with aluminum cylinders and coated walls??? Sometimes I think they engineer these things just way to close to the limits, and then tune them down to make them "workable"

Just my rant---sorry

 

The same thing happened to my hemi at right about 40000 miles. It threw a mis fire in cylinder 6 code so i pulled the plugs and the tab on each plug was bent completely down to the electrode. I feared the worst and was correct. The ring/land had come apart and ping ponged around in the cylinder.
Power train took care of it...thank god. However i had to take it to two dealerships as the first one AVONDALE DODGE said nothing was wrong with it and that i must have gaped my plugs wrong. Lou Grubb Dodge took care of it with no issues. It took them about 15 minutes to diagnose it with a scope.

This is a pic of a dead hemi in it's coffin. I was hoping to get a pic of it before they put it back together but got there to late.




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