Roller pin materials for enhanced cam durability

A method of enhancing the durability of a cam lobe surface on a rotatable camshaft for an internal combustion engine and minimizing galling effects on said cam lobe surface comprising the steps of:

• providing a cam follower roller which contacts and follows said cam lobe surface, said cam follower roller being subject to cyclical mechanical loading by said cam lobe surface as said camshaft rotates;
• and
• providing a roller pin for mounting said cam follower roller, said roller pin being maintained at a spaced distance from said cam lobe surface such that said roller pin is free from contacting said cam lobe surface;
• wherein said roller pin is made from leaded manganese silicon bronze alloy characterized by low friction, high wear resistance, scuff resistance, sufficient corrosion resistance to prevent gross chemical attack of the pin surface by oil contaminants, sufficient ability to embed hard debris and oil contaminants without scuffing, and sufficient fatigue resistance to carry the cyclical mechanical loads imposed on the cam roller;
• wherein said leaded manganese silicon bronze alloy of said roller pin comprises 58.0-63.0% by weight copper, 2.0-3.5% by weight manganese, 0.5-1.5% by weight silicon, 0.40-3.0% by weight lead 0.50% by weight maximum iron, 0.25% by weight maximum nickel 0.25% by weight maximum tin and 0.30% by weight maximum aluminum, with the remainder zinc.