What happen

[BILL-C]

A ring end gap measurement would probably put this to bed in a hurry. Dying to know!

[jed]

Sorry for the delay in responding. I got back to work intending to check ring gaps are other suggestions
And found the weekend cleaning crew had thrown everything away except the piston.
I was very disappointed but shit happens.
I can almost guarantee that the ring gap was not over .030. But I agree there was a lot of heat (duh) at the ring gap.
I wish I was smart enough to understand the chemical reactance that was going on in that space. But I'm not.
It is fun and educational to try to figure and understand what happened.
Thanks again for the input

[allencr267]

With a top ring not rotating and that piston design's extra volume between 1st & 2nd, that would concentrate a lotta heat in one spot.

[BILL-C]

Can you measure the width of the aluminum lump where the end gap of ring was? The end gap would have been at least that wide.

[BILL-C]

Can you measure the width of the aluminum lump where the end gap of ring was? The end gap would have been at least that wide.

[jed]

As close as I can estimate the slot is .048/.052.
But as I stated at the time if assembly the gap
Was not over .030.

[rockosocko]

Maybe send pics and info directly to Diamond?
I'm sure they've seen a few weird things happen to pistons..

Just my .02
E

[cjperformance]

As i said before, 'File fit rings with burs/chipping left on the end edge. Picks up some piston material and sticks the ring in the groove holding the gap area away from the bore, torched piston'

Your ring gap now measures larger as the outside face of the ring has some wear from the trauma. This is not rocket science. The rings simply were not deburred properly.

[jed]

If "the file fit rings had burs and chips on the end edge" I don't think the ring would fit in the ring grove and if it was forced
Into the grove the ring would not turn in the grove.
All file fit rings are lightly debuted and install easily in the grove and are checked that they smoothly turn in the grove.

[Geoff2]

I have filed heaps of file fit rings, never had one that jammed in the ring groove.

[econo racer]

Is there a sleeve in that cylinder?

[cjperformance]

I have filed heaps of file fit rings, never had one that jammed in the ring groove.

When done properly they dont!
All it takes is enough of a burr to nearly take up the land clearance, ring still goes in, spins in the groove when felt by hand etc. If the burr is on the lower/loaded side it picks up some piston material and game over.

[jed]

No sleeve.