So, I've got my block fully disassembled and found carbon deposits at the base of the cylinder walls, inside the pistons, on the piston skirts & tops and the oil rings were cemented into place with carbon. I had piston slap and some knocking that wasn't going away at idle. The cylinders still have cross-hatches so I'm thinking the collapsed oil rings and clogged oil holes in the piston skirts and carbon deposits on the skirts may have caused the slap. Am I deluded ? What do I need to check ? The main and rod bearings are worn and have some scrapping from dirt or carbon. What should I check ?

year/engine/miles/intent?

 

I'd likely say bearings and rings.