A high-performance camshaft retainer having a plurality of windage relief holes embodying an as-pressed configuration and a method of manufacturing the same, wherein the windage relief holes are molded from a powdered metal matrix and provided in an as-molded detail.

A high-performance camshaft retainer having a plurality of windage relief holes embodying an as-pressed configuration and a method of manufacturing the same, wherein the windage relief holes are molded from a powdered metal matrix and provided in an as-molded detail.

An improved air-cooled aviation engine includes a compact combustion chamber having an intake valve opening, an exhaust valve opening, and a generally elliptical shape. The elliptical shape has a major axis and a minor axis, with the major axis intersecting both the intake valve opening and the exhaust valve opening. In some examples, the major axis is the same length or shorter than a diameter of a cylinder bore of the engine, and the minor axis is smaller than the major axis. Combustion is thus constrained to a smaller area than that of the cylinder bore.

An improved air-cooled aviation engine includes a compact combustion chamber having an intake valve opening, an exhaust valve opening, and a generally elliptical shape. The elliptical shape has a major axis and a minor axis, with the major axis intersecting both the intake valve opening and the exhaust valve opening. In some examples, the major axis is the same length or shorter than a diameter of a cylinder bore of the engine, and the minor axis is smaller than the major axis. Combustion is thus constrained to a smaller area than that of the cylinder bore.

Provided is a valve seat insert for an internal combustion engine, which has both an excellent heat dissipation property and excellent wear resistance. The valve seat insert for an internal combustion engine is used while being press-fitted into an aluminum alloy cylinder head, is made of an iron-based sintered alloy, is formed by integrating two layers of a functional member side layer and a supporting member side layer, and has a plating film on at least an outer peripheral side. The plating film is preferably a copper plating film. The plating film is a plating film having a thickness of 1 to 100 μm and a hardness of 50 to 300 HV, and the hardness of the plating film is adjusted so as to satisfy a range of 1.05 to 4.5 times hardness of the cylinder head in Vickers hardness HV. Pores contained in the valve seat insert are preferably sealed with a curable resin before plating treatment. Consequently, a valve seat insert for an internal combustion engine which does not go through complicated processes, is not accompanied by a significant decrease in wear resistance compared with the prior art, and has an excellent heat dissipation property is provided. If a roughened surface region is further formed at at least one portion on the outer peripheral surface of the valve seat insert in addition to the plating film, a falling out resistance property is improved. The same effect can be obtained even if the valve seat insert is a single layer of only the functional member side layer.

Provided is a valve seat insert for an internal combustion engine, which has both an excellent heat dissipation property and excellent wear resistance. The valve seat insert for an internal combustion engine is used while being press-fitted into an aluminum alloy cylinder head, is made of an iron-based sintered alloy, is formed by integrating two layers of a functional member side layer and a supporting member side layer, and has a plating film on at least an outer peripheral side. The plating film is preferably a copper plating film. The plating film is a plating film having a thickness of 1 to 100 μm and a hardness of 50 to 300 HV, and the hardness of the plating film is adjusted so as to satisfy a range of 1.05 to 4.5 times hardness of the cylinder head in Vickers hardness HV. Pores contained in the valve seat insert are preferably sealed with a curable resin before plating treatment. Consequently, a valve seat insert for an internal combustion engine which does not go through complicated processes, is not accompanied by a significant decrease in wear resistance compared with the prior art, and has an excellent heat dissipation property is provided. If a roughened surface region is further formed at at least one portion on the outer peripheral surface of the valve seat insert in addition to the plating film, a falling out resistance property is improved. The same effect can be obtained even if the valve seat insert is a single layer of only the functional member side layer.

A valve stem seal includes an elastomeric annular seal body including a first seal body section and a second seal body section. The first seal body section includes a first seal lip configured to sealingly abut against the valve stem to delimit an oil space and a second seal lip axially spaced from the first seal lip and configured to sealingly abut against the valve stem to delimit an air space. The first seal body section includes an annular channel in a radially inner wall between the first seal lip and the second seal lip that is spaced from the valve stem when the valve stem seal is mounted on the valve stem, and the surface of the channel includes an undercut configured to facilitate a deformation of the second seal lip toward the first seal lip.

A copper alloy for valve seats, and more particularly a copper alloy for valve seats with improved wear resistance, contains 12 to 24% by weight of Ni, 2 to 4% by weight of Si, 7 to 13% by weight of Cr, 20 to 35% by weight of Fe, and a balance of Cu and other impurities.

A copper alloy for valve seats, and more particularly a copper alloy for valve seats with improved wear resistance, contains 12 to 24% by weight of Ni, 2 to 4% by weight of Si, 7 to 13% by weight of Cr, 20 to 35% by weight of Fe, and a balance of Cu and other impurities.

Aspects of the present invention relate to a valve seat (20) for a poppet valve of an internal combustion engine, wherein the poppet valve comprises a head and a stem behind the head, the valve seat comprising: an aperture (21) configured to form a seal with the head of the poppet valve when the poppet valve is in a closed position; and a peripheral body (22) defining, at least in part, one or more ports (23) shaped like e.g. grooves and sized to enable injection of liquid or gas from a cylinder head of the internal combustion engine into a gas stream behind the head of the poppet valve.