Which statement is true regarding the compatibility of piston rings with cylinder types?

The compatibility of piston rings with cylinder types is crucial for the effective operation and longevity of an engine. The statement that both cast iron rings can only be used with chrome-plated cylinders and that chrome-plated rings are allowed with plain steel cylinders provides insight into the relationship between materials used in engine components.

Cast iron rings are traditionally used with chrome-plated cylinders due to the wear resistance and durability that this combination provides. Chrome-plating enhances the surface hardness of the cylinder, which complements the wear characteristics of cast iron rings, making them ideal for each other as they tend to prevent premature wear and ensure a better sealing performance.

On the other hand, using chrome-plated rings with plain steel cylinders is permissible. Chrome-plated rings possess excellent wear resistance and are designed to handle the abrasion that may occur with a steel surface. This combination can lead to improved engine efficiency and a reduction in friction, which ultimately enhances performance and longevity.

The correctness of both statements underlines the importance of selecting the appropriate materials for piston rings based on the type of cylinder to maintain optimal engine function and durability. Understanding these compatibility factors is vital for anyone involved in the maintenance and repair of reciprocating engines.