What is Gudgeon Pin ?
A gudgeon pin in the Piston skirt performs the crosshead function in trunk Piston engine.
The Pin is made of steel with a hard, polished surface of the bearing. It can be fitted to the skirt or free to float and rotate, to limit axial movement.
A single sleeve bearing bush is pushed into an eye at the end of the connecting rod. During the induction stroke of the four stroke cycle, the piston load is reversed and this enables oil to spread over the lowered surface of the bearing.
The supply of oil in the engine is produced to the bottom by means of oil holes in the crankshaft and thus through the connecting rod.
A non return valve may be fitted in the foot of this rod to prevent back -flow of oil under gravitational force at the bottom of each stroke.