A closure element for a fluid end assembly that has two or more recessed grooves formed in its outer surface. The grooves are axially offset. A seal is placed in one and only one of the grooves. As wear occurs, the seal is relocated to one of the other grooves. Instead of a series of axially offset grooves in a single closure element, a kit may be formed from two or more otherwise identical closure elements, each with a single recessed groove at a different axial position. Another closure element has a series of ledge-like surfaces defining spaces within which a seal may be received. One outer surface surrounds one or more of the other surfaces. A seal is placed in one and only one of the spaces. As wear occurs, the seal is relocated to one of the other spaces.

A pump includes a cam plate, and an input shaft for rotationally driving the cam plate. A pump housing at least partially surrounds the cam plate and defines a cam plate oil reservoir around at least a portion of the cam plate. A bearing support is at least partially disposed within the cam plate oil reservoir. The bearing support defines a bearing oil reservoir at least partially surrounding a portion of the input shaft. At least one passage extends between the bearing oil reservoir and the cam plate oil reservoir. Dynamic motion imparted on oil within the cam plate oil reservoir facilitates migration of oil from the cam plate oil reservoir through a bearing at least partially supported by the bearing support into the bearing oil reservoir and through the at least one passage into the cam plate oil reservoir.

An opposed piston engine has a driveshaft with at least one combustion cylinder positioned between opposing, curvilinear shaped cams mounted on the driveshaft, where the center axis of the combustion cylinder is parallel with but spaced apart from the driveshaft axis. A piston assembly is disposed in each end of the cylinder, with one piston assembly engaging one cam and the other piston assembly engaging the other cam. Each piston assembly includes a cam follower that can move along a curvilinear shaped cam to reciprocate the piston assembly within the cylinder. The combustion cylinder includes an intake port in fluid communication with an annular intake channel formed in the engine block in which the cylinder is mounted, and an exhaust port in fluid communication with an annular exhaust channel formed in the engine block.

A closure element for a fluid end assembly that has two or more recessed grooves formed in its outer surface. The grooves are axially offset. A seal is placed in one and only one of the grooves. As wear occurs, the seal is relocated to one of the other grooves. Instead of a series of axially offset grooves in a single closure element, a kit may be formed from two or more otherwise identical closure elements, each with a single recessed groove at a different axial position. Another closure element has a series of ledge-like surfaces defining spaces within which a seal may be received. One outer surface surrounds one or more of the other surfaces. A seal is placed in one and only one of the spaces. As wear occurs, the seal is relocated to one of the other spaces.

An opposed piston engine has a driveshaft with at least one combustion cylinder positioned between opposing, curvilinear shaped cams mounted on the driveshaft, where the center axis of the combustion cylinder is parallel with but spaced apart from the driveshaft axis. A piston assembly is disposed in each end of the cylinder, with one piston assembly engaging one cam and the other piston assembly engaging the other cam. Each piston assembly includes a cam follower that can move along a curvilinear shaped cam to reciprocate the piston assembly within the cylinder. The combustion cylinder includes an intake port in fluid communication with an annular intake channel formed in the engine block in which the cylinder is mounted, and an exhaust port in fluid communication with an annular exhaust channel formed in the engine block.

A pump includes a pump body. The pump may also include a pump mounting flange configured to mount the pump to an engine flange including four clocked mounting holes. The pump mounting flange may include a first set of four mounting holes corresponding to the four clocked mounting holes in a first orientation. The pump mounting flange may include a second set of four mounting holes corresponding to the four clocked mounting holes in a second orientation.

A closure element for a fluid end assembly that has two or more recessed grooves formed in its outer surface. The grooves are axially offset. A seal is placed in one and only one of the grooves. As wear occurs, the seal is relocated to one of the other grooves. Instead of a series of axially offset grooves in a single closure element, a kit may be formed from two or more otherwise identical closure elements, each with a single recessed groove at a different axial position. Another closure element has a series of ledge-like surfaces defining spaces within which a seal may be received. One outer surface surrounds one or more of the other surfaces. A seal is placed in one and only one of the spaces. As wear occurs, the seal is relocated to one of the other spaces.

A pump includes a pump body. The pump may also include a pump mounting flange configured to mount the pump to an engine flange including four clocked mounting holes. The pump mounting flange may include a first set of four mounting holes corresponding to the four clocked mounting holes in a first orientation. The pump mounting flange may include a second set of four mounting holes corresponding to the four clocked mounting holes in a second orientation.

A pump includes a cam plate, and an input shaft for rotationally driving the cam plate. A pump housing at least partially surrounds the cam plate and defines a cam plate oil reservoir around at least a portion of the cam plate. A bearing support is at least partially disposed within the cam plate oil reservoir. The bearing support defines a bearing oil reservoir at least partially surrounding a portion of the input shaft. At least one passage extends between the bearing oil reservoir and the cam plate oil reservoir. Dynamic motion imparted on oil within the cam plate oil reservoir facilitates migration of oil from the cam plate oil reservoir through a bearing at least partially supported by the bearing support into the bearing oil reservoir and through the at least one passage into the cam plate oil reservoir.

A closure element for a fluid end assembly that has two or more recessed grooves formed in its outer surface. The grooves are axially offset. A seal is placed in one and only one of the grooves. As wear occurs, the seal is relocated to one of the other grooves. Instead of a series of axially offset grooves in a single closure element, a kit may be formed from two or more otherwise identical closure elements, each with a single recessed groove at a different axial position. Another closure element has a series of ledge-like surfaces defining spaces within which a seal may be received. One outer surface surrounds one or more of the other surfaces. A seal is placed in one and only one of the spaces. As wear occurs, the seal is relocated to one of the other spaces.