Alright, I have been using a piston ring groove cleaning tool to get the gunk out of the grooves. My brother was helping me and I think he messed up one of the pistons. It appears he did not set the tool properly and the groove cleaner dug into the piston. This is one of the pistons which doesn't look too bad, the other two he did look worse. Should I be replacing these pistons now with different ones? What would happen if I placed them back into the engine? Sorry for the question, but I honestly don't know and have not been able to find the information when searching online.

Robert

 

The bottom of the groove, the surface you can see in the photo, isn't important. The sides however are a critical sealing surface. Scratches or gouges will cause the engine to have massive blowby.

I've don't think I've ever seen one of those tools NOT damage a piston beyond repair. Most likely, if you used that, you need new pistons.

Best way to clean up used pistons is a toothbrush and lacquer thinner.

 

Let me make a suggestion. Its old school but effective. When cleaning a piston soak it with brake cleaner and scrub it with a hand wire brush or powered if you are careful. Also, the piston looks OK.

 

Old piston rings cut in half works well to. I attempted to use one of the tools once idk where it landed.

 

Brakekleen and a brass wire brush or brass wire wheel. The brass is softer than the aluminum so it doesn't remove any material.