Piston Textures - holding carrying of oils by hoser..

These are pictures of pistons installed in a 440cc snowmobile engine I have, it is fan cooled, 
the pistons were like this when I bought the engine, my guess is the former owner was
experimenting with different textures to see what one worked best to get the piston to hold 
more oil or to get a better film of oil between the piston and cylinder wall.

I put a set of rings into this engine when I bought it and both pistons wear was the same.

This piston they drilled dimples all the way around the piston look close and you can see
just how far below the ring they located the dimples


This piston they scribed lines all the way around the piston.

I have read technical test data on surface textures created by blasting with a media like 
glass beads etc. this showed favorable results however these were done to 4 stroke engines.
You want good oil protection also see Piston Prep Before Use
1999


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