Did you remove the rings and inspect behind them?

Behind them? What should I have looked for?

You are looking for sand that got trapped behind the rings. As you move in the ring around in the piston slot you might actually feel the grit.

Rand

Trapped behind or embedded into the rings and piston grooves hard to see unless you remove the rings then look at the parts with bright light and magnifying glass, amazing what you don't see with 20/20 vision and without a magnifying glass, you would be amazed at the amount of dirt still left on what people thing are "clean parts" until you look at them with a magnifying glass.

20/20 vison?

What he hell is that? I'm over 50 and can't see shit anymore without glasses!

Rand