I would be concerned about the ring lands / spacing if the piston was forced out across a ridge. Measure them before installing new rings.

I am also very curious why the ring grooves are so impacted with carbon/crap. Will you be so kind as to enlightnen me/us on what besides burning SVO might have led to this problem (possibilities such as extended idling, oil additives with Teflon/PTFE, past engine problems et al)?

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Gone to the dark side

- Jeff