operation fix mc10

[David Luciani]

i inspected the piston again as the damaged area is making me insane. 
in the ruined section the aluminum seems to have "sugared" in the ring area and gotten brittle.
there's also dragged aluminum on the pistons lower skirt.
the weird part is it happened at the back intake port not anywhere near the exhaust ports.
only thing i know of that could've caused this would be lost lubrication but can't figure out how that happened only on those three ports.
but i'm also leaning towards a sudden air leak overheating the piston .
 i was adding high needle flow at the time but it still went away on the straight towards the end .
finally it could just be the piston was worn out and started chipping on the edge  and over heated.
i've rarely run a mcculloch as long as i ran the mc10 and the piston was used when i got it so i might've just worn out the piston.

i'm trying to figureout what went wrong so i don't get an instant replay.
so i am researching reading piston damage .
here are some neat links.

reading piston damage link to pix and text

another link similar text better pix

good text mostly

this next link is excellent good pix and lots of text
both two and fouyr stroke piston reading of damage

really good pix and text on piston failure

   

i'm gonna try this on the new piston may be a bad idea on mcculloch.
but i will never know if i don't try it!
exhaust bridge lube hole on piston

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