A tight pin may also change the expansion characteristics of the piston and cause scuffing or seizure on the piston thrust faces. When the piston is unable to expand correctly along the pin axis it will expand at 90° to the pin and force the thrust faces of the piston hard against the cylinder wall.
Before the piston is fitted, there are several clearance checks to be made. The first of these is the fit of the piston pin. It should be an easy slide fit, slipping through the piston under its own weight. A tight pin is to be avoided as this will overload the sides of the piston when the engine is running. At high engine speeds the crankshaft tends to whip and, if the pin is tight, this load will be transferred to the side of the piston, possibly distorting it and causing seizure.
the wrist pin is held in by clips
93wellcraft 1 year ago
A tight pin may also change the expansion characteristics of the piston and cause scuffing or seizure on the piston thrust faces. When the piston is unable to expand correctly along the pin axis it will expand at 90° to the pin and force the thrust faces of the piston hard against the cylinder wall.
PilotOdyssey 4 years ago
Before the piston is fitted, there are several clearance checks to be made. The first of these is the fit of the piston pin. It should be an easy slide fit, slipping through the piston under its own weight. A tight pin is to be avoided as this will overload the sides of the piston when the engine is running. At high engine speeds the crankshaft tends to whip and, if the pin is tight, this load will be transferred to the side of the piston, possibly distorting it and causing seizure.
PilotOdyssey 4 years ago
Piston Two of Two, they came out of a match set for a 440 ROTAX
PilotOdyssey 4 years ago