S&S Cycle 66-84 BT 3-7/16in Piston Ring Set - .040in

These S&S Cycle piston rings are moly faced, meaning they have a coating of molybdenum compound. This advanced surface treatment is key to their performance, offering improved wear resistance, better heat tolerance, and more effective sealing within the cylinder bore. This is important because well-sealed rings prevent combustion gases from escaping past the piston, which helps maintain engine power and efficiency. The .040 inch size means these rings are intended for a cylinder bore that has been machined to be 0.040 inches larger than its original specification, typically done during an engine rebuild to correct wear or increase displacement.

The moly coating on these rings is a practical choice for engine builders looking for a durable and reliable component. It helps the rings seat properly against the cylinder wall, reducing friction and heat buildup, which can extend the life of both the rings and the cylinder itself. For anyone rebuilding a 1966-1984 Big Twin engine and needing to replace or upgrade their piston rings, this set from S&S Cycle offers a well-built option designed for improved performance and longevity.