A cam follower is provided. The cam follower includes a polycrystalline diamond element, including an engagement surface. The engagement surface of the polycrystalline diamond element is positioned on the cam follower for sliding engagement with an opposing engagement surface of a cam. The cam includes at least some of a diamond reactive material.

A cam follower is provided. The cam follower includes a polycrystalline diamond element, including an engagement surface. The engagement surface of the polycrystalline diamond element is positioned on the cam follower for sliding engagement with an opposing engagement surface of a cam. The cam includes at least some of a diamond reactive material.

A wear-resistant copper-based alloy includes: at least one selected from the group made of molybdenum, tungsten, and vanadium and niobium carbide; chromium in an amount of less than 1.0% in terms of wt %; and a matrix and hard particles dispersed in the matrix, in which the hard particles include niobium carbide and at least one selected from the group made of NbCMo, NbCW, and NbCV around the niobium carbide.

A wear-resistant copper-based alloy includes: at least one selected from the group made of molybdenum, tungsten, and vanadium and niobium carbide; chromium in an amount of less than 1.0% in terms of wt %; and a matrix and hard particles dispersed in the matrix, in which the hard particles include niobium carbide and at least one selected from the group made of NbCMo, NbCW, and NbCV around the niobium carbide.

In an engine valve, a first sliding area formed at a valve head side in an outer face of a valve stem, and sliding along a stem guide, a second sliding area formed at an opposite side from the valve head side, and sliding along the stem guide, and a first small diameter area formed between the first sliding area and the second sliding area are formed. Further, in the engine valve, a length, in an axial direction of the valve stem, of the first sliding area abutting on the stem guide at a position where the engine valve is fully opened is longer as compared with a length, in the axial direction of the valve stem, of the second sliding area abutting on the stem guide at a position where the engine valve is fully closed.

In an engine valve, a first sliding area formed at a valve head side in an outer face of a valve stem, and sliding along a stem guide, a second sliding area formed at an opposite side from the valve head side, and sliding along the stem guide, and a first small diameter area formed between the first sliding area and the second sliding area are formed. Further, in the engine valve, a length, in an axial direction of the valve stem, of the first sliding area abutting on the stem guide at a position where the engine valve is fully opened is longer as compared with a length, in the axial direction of the valve stem, of the second sliding area abutting on the stem guide at a position where the engine valve is fully closed.

A reciprocating cylinder seal assembly has an elastomeric seal with a radially inwardly directed oil sealing lip and a radially inwardly directed gas sealing lip, wherein both lips are in elastomeric-to-metal sealing contact with a reciprocating engine liner. The assembly further has a U-shaped seal retainer that is attached to the elastomeric seal, where the U-shaped seal retainer is placed in direct intimate contact with a cylindrical engine housing. The U-shaped seal retainer and a reciprocating engine housing may be separated by and be in contact with a major portion of a J-shaped gas shield with a hook portion that is located between the oil sealing lip and a manifold port, where the hook portion of the J-shaped gas shield has a metal backer ring embedded in it.

A reciprocating cylinder seal assembly has an elastomeric seal with a radially inwardly directed oil sealing lip and a radially inwardly directed gas sealing lip, wherein both lips are in elastomeric-to-metal sealing contact with a reciprocating engine liner. The assembly further has a U-shaped seal retainer that is attached to the elastomeric seal, where the U-shaped seal retainer is placed in direct intimate contact with a cylindrical engine housing. The U-shaped seal retainer and a reciprocating engine housing may be separated by and be in contact with a major portion of a J-shaped gas shield with a hook portion that is located between the oil sealing lip and a manifold port, where the hook portion of the J-shaped gas shield has a metal backer ring embedded in it.

A reciprocating cylinder seal assembly has an elastomeric seal with a radially inwardly directed oil sealing lip and a radially inwardly directed gas sealing lip, wherein both lips are in elastomeric-to-metal sealing contact with a reciprocating engine liner. The assembly further has a U-shaped seal retainer that is attached to the elastomeric seal, where the U-shaped seal retainer is placed in direct intimate contact with a cylindrical engine housing. The U-shaped seal retainer and a reciprocating engine housing may be separated by and be in contact with a major portion of a J-shaped gas shield with a hook portion that is located between the oil sealing lip and a manifold port, where the hook portion of the J-shaped gas shield has a metal backer ring embedded in it.

A reciprocating cylinder seal assembly has an elastomeric seal with a radially inwardly directed oil sealing lip and a radially inwardly directed gas sealing lip, wherein both lips are in elastomeric-to-metal sealing contact with a reciprocating engine liner. The assembly further has a U-shaped seal retainer that is attached to the elastomeric seal, where the U-shaped seal retainer is placed in direct intimate contact with a cylindrical engine housing. The U-shaped seal retainer and a reciprocating engine housing may be separated by and be in contact with a major portion of a J-shaped gas shield with a hook portion that is located between the oil sealing lip and a manifold port, where the hook portion of the J-shaped gas shield has a metal backer ring embedded in it.