Abstract: An improved, light weight tappet and method of manufacturing such a tappet. The tappet is comprised of a light weight sleeve to which a hardened disk is metallurgically bonded.

Abstract: A valve seat-bonded cylinder head, in which a valve seat is bonded to a cylinder head unit, which valve seat is formed of material different from and harder than that of said cylinder head unit, wherein the valve seat is bonded to the cylinder head unit by solid-state diffusion, without forming a melting reaction layer therebetween, and a plastic deformation layer is formed on the bonding boundary at least on the cylinder head unit side, thereby allowing for an increase in the bonding strength, and reduction in the size of the valve seat area.

Abstract: A valve seat insert for use in forming a metallurgically bonded valve seat for a light alloy casting. The valve seat insert is comprised of a base formed from a sintered material selected from the group of ferrous, copper or nickel and is provided with a coating selected from the group of copper, tin, zinc, silicon, aluminum or silver or an alloy thereof. The coating forms an eutectic alloy with the aluminum of the cylinder head which eutectic alloy has a melting point lower than that of either the aluminum or the coating.

Abstract: A method for affixing a valve seat insert into a cylinder head recess using pressure or pressure in conjunction with resistance welding. The preferred method avoids the creation of tensile stresses within the valve seat insert during installation into the cylinder head. Further, the method reduces the size of an opening of the valve seat insert during installation. In addition, the application of pressure and the respective shapes of the recess and valve seat insert are such that a moment is not created in the insert which would result in the application of tensile forces on the insert. A lower surface opposite the combustion chamber of the valve seat insert is disposed at an angle to the opening within a range of .+-.15.degree. to a plane which is perpendicular to the axis of the opening. Additionally, the valve seat insert may comprise multiple components which, when resistance welded to the cylinder head, form a plurality of intermetallic layers having gradually varying coefficients of thermal expansion.

Abstract: A method for affixing a valve seat insert into a cylinder head recess using pressure or pressure in conjunction with resistance welding. The preferred method avoids the creation of tensile stresses within the valve seat insert during installation into the cylinder head. Further, the method reduces the size of an opening of the valve seat insert during installation. In addition, the application of pressure and the respective shapes of the recess and valve seat insert are such that a moment is not created in the insert which would result in the application of tensile forces on the insert. A lower surface opposite the combustion chamber of the valve seat insert is disposed at an angle to the opening within a range of .+-.15.degree. to a plane which is perpendicular to the axis of the opening. Additionally, the valve seat insert may comprise multiple components which, when resistance welded to the cylinder head, form a plurality of intermetallic layers having gradually varying coefficients of thermal expansion.