tweaker

Or perhaps it applies to all ABC type engine.
Is it normal to have a 1/8 to 1/4 in shined up
spot(for lack of a better word)Right at the top of the piston?
It has a great cold pinch.
My dead magnun 53 doesn't have that.
Steve

proptop

My Feedback: (8)

Yeah, that's the area where the piston's sealing. It'll be a bit different for each engine, but basically, that's the area that's being "polished" by contact w/ the sleeve. Just don't run it too cool (rich) or too lean, and you'll have a good engine for quite awhile (barring unforseen circumstances of course) If you run it too rich, the piston will wear excessively, then when you lean it out and it gets hot, the sleeve will expand more, and you'll loose compression.

tweaker

Thanks,
(barring unforseen circumstances)That's good!LMHO
you guys are great here.
I have had close to a dozen engines.
Never broke an ABC in 4 cycle mode but very,very close
Result we're poor, then take into account the altitude i'm at
3700 ASL and it becomes impossible to make any power.

Steve