piston clearance

lateral space of the pistons

[Wipsplash]

First piston looks forged and second cast. Forged pistons need more clearance because they are denser aluminum and expand more than cast when heated.

[stevenbelue]

I think the movement on the first piston is completely normal, that's not to say the piston to wall clearance is not excessive. We're talking about human hairs and not at the crown but down at the skirts and can not be judged by the naked eye or piston rock.

[Coyotesmilespergallon]

Those pistons 2618 forged will do that brand new. They are smaller at the top of the piston than and the skirts…. That looked to be perfectly normal clearance at the very top. If you get them too tight the will seize or bind. There is a fine line. So far what I’ve found is .0004 is ok.

[osbornebay]

15-20 mil on cast and 35-40 mil on forged. The first one looks like 800 mil gap.