Abstract: A two-piece valve stem guide allows the guide to be reamed in-place without damaging an installed valve seal. A first section of the guide is press fitted into an axially extending bore of an internal combustion engine component. Next, a multi-piece seal comprising a metallic retainer, elastomeric seal element and optional spring is inserted into the bore. Then a second section of the stem guide is partially installed into the bore. The two sections are reamed to create a common inner radial diameter that is adapted to receive a valve stem. Finally, the second section is pressed axially downward, engaging the seal and forcing the elastomeric seal element radially inwardly until it comes into contact with an installed valve stem.

Abstract: A piston ring assembly comprises a piston ring, a spring for providing an outward force on the ring, and a rail for engaging a cylinder wall. The piston ring is retained in a piston groove in a piston. During upward movement of the piston in a cylinder, oil above the ring face is forced between the first front surface and the top surface into the piston groove to an inner portion of the piston groove. During downward movement of the piston, the downward force urges cocking of the piston ring about the ring face to tilt the ring face away from the cylinder wall, leaving the lower front of the ring face in scraping abutment with the cylinder wall.

Abstract: A piston ring comprises a generally annular ring body with a series of slots spaced circumferentially about an outer periphery of the ring body, each of the slots extending radially inwardly from the outer periphery. A hinge point is formed between adjacent slots, the hinge point corresponding to the outer periphery of the ring body. A wear surface material comprising ceramics is inlayed into each of the slots. The piston ring is formed by cutting a series of slots such as scallops about the outer periphery of the ring body that extend radially inwardly from the outer periphery and inlaying a wear surface material into the slots. The inlaying step may comprise the further step of thermally spraying the material into the slots. Then the outer periphery of the ring body may be ground to expose the wear surface material and create a finished outer surface.

Abstract: An annular composite insert is cast which includes distinct particles such as cast iron dispersed throughout the base metallic alloy. The insert is then placed in a piston mold, and a piston cast such that the insert maintains a radially outer face generally flush with a radially outer surface of a piston head of the piston. The base metal of the poured piston is preferably the same as that of the insert so that the insert bonds to the piston head and shares the same thermal expansion characteristics. The insert is machined to form grooves adapted to receive a piston ring. The particles of the insert are exposed to provide superior wear resistance, support to the piston ring so that microwelding is reduced, and also to act as a dry lubricant in a preferred embodiment.

Abstract: A valve stem seal assembly adapted for a reciprocable valve stem disposed within a valve guide can tolerate major variations in the guide height. The assembly includes a lower hollow cylindrical shell and an upper hollow cylindrical shell, both disposed about the valve guide. The upper hollow cylindrical shell is capable of being telescopically received within the lower hollow cylindrical shell in a slip-fit relationship. A seal member is secured to the upper hollow cylindrical shell, the seal member extending radially inwardly so as to engage the reciprocable valve stem and extending axially downwardly so as to engage the valve guide.