Abstract: An exhaust valve includes a stem extending to a valve end. The valve end includes a pressure relief apparatus. An engine assembly includes a casing defining a cylinder bore, a combustion chamber and an exhaust passage. The combustion chamber is disposed between the exhaust passage and the cylinder bore. The engine assembly also includes a piston movable in the cylinder bore. The engine assembly further includes an exhaust valve movable between a first position blocking fluid communication through the exhaust passage and a second position allowing fluid communication through the exhaust passage. The exhaust valve includes a pressure relief apparatus configured to allow fluid communication through the exhaust valve from the cylinder bore to the exhaust passage when the exhaust valve is in the first position and a predetermined pressure threshold occurs in the cylinder bore between the exhaust valve and the piston.

Abstract: An exhaust valve includes a stem extending to a valve end. The valve end includes a pressure relief apparatus. An engine assembly includes a casing defining a cylinder bore, a combustion chamber and an exhaust passage. The combustion chamber is disposed between the exhaust passage and the cylinder bore. The engine assembly also includes a piston movable in the cylinder bore. The engine assembly further includes an exhaust valve movable between a first position blocking fluid communication through the exhaust passage and a second position allowing fluid communication through the exhaust passage. The exhaust valve includes a pressure relief apparatus configured to allow fluid communication through the exhaust valve from the cylinder bore to the exhaust passage when the exhaust valve is in the first position and a predetermined pressure threshold occurs in the cylinder bore between the exhaust valve and the piston.

Abstract: A piston assembly includes an annular body defining a groove, with a ring disposed within the groove. The piston assembly includes a centering device disposed within the groove between an inner face of the ring and a root of the groove. The centering device centers the ring concentrically within the groove when the ring is in an uncompressed condition, prior to installation into a bore of an engine block, to prevent the inner face of the ring from moving radially outward beyond an outer edge of the groove when the ring is in the uncompressed condition.

Abstract: A material for use as a centering device for centering a ring within a groove of a piston when the ring is in an uncompressed free state is manufactured from a mixture of approximately eighty (80) parts by mass petrolatum with approximately twenty (20) parts by mass carnauba wax based on one hundred (100) parts by mass of the mixture. The petrolatum and the carnauba wax are heated to a liquid state and then combined to form the mixture. Once combined, the mixture is maintained in a liquid state for a pre-defined period of time, after which the mixture is cooled to room temperature to form a block of the mixture. Once cooled, layers of the mixture are scraped from the block. Each layer includes a maximum layer thickness equal to or less than 2.5 mm.

Abstract: A piston assembly includes an annular body defining a groove, with a ring disposed within the groove. The piston assembly includes a centering device disposed within the groove between an inner face of the ring and a root of the groove. The centering device centers the ring concentrically within the groove when the ring is in an uncompressed condition, prior to installation into a bore of an engine block, to prevent the inner face of the ring from moving radially outward beyond an outer edge of the groove when the ring is in the uncompressed condition.