Piston Pin Polini 12x31,5

What is a piston pin?

The piston pin, also called gudgeon pin or wrist pin, is a cylindrical component made of hardened steel that connects the piston to the connecting rod in internal combustion engines. The piston pin allows the piston to move linearly in the cylinder, transmitting power to the connecting rod and crankshaft.

The piston pin sits in the pin boss of the piston and is held in place by retaining circlips. Each time the piston is reassembled, the circlips and the small end bearing must be replaced and the entire unit lubricated.