Valve seat inserts

A valve seat insert for a water-cooled internal combustion engine and comprising an annular body having two adjacent annular surfaces which are normal to one another and which fit into a corresponding rabbet in the engine, a channel provided in one of said insert surfaces extending around the valve seat insert and being closed by an associated rabbet surface, and angularly spaced U-shaped notches extending from an edge between said two insert surfaces to said channel and opening onto one of said insert surfaces for the flow of engine cooling water through said passage.

A method of manufacturing of a water-cooled internal combustion engine of the kind comprising at least one cylinder having valve-controlled inlet and exhaust ports communicating with said cylinder, the method comprising casting a portion of the engine with a port, with passages for cooling water and with a part in which a rabbet is to be formed for receiving a valve seat insert, the rabbet-forming part of the casting being annular with a continuous outer surface in which the rabbet is formed and an inner surface forming a surface of the cooling water passage, the inner surface being cast with an angularly-spaced succession of projections and depressions therearound, such that the edge between two surfaces defining the rabbet, when formed, passes through the depressions to form, between adjacent projections, apertures leading into the rabbet, forming said casting with said rabbet and then fitting in said rabbet a valve seat insert including an annular body having two adjacent annular surfaces that are normal to one another and which engage said rabbet surfaces, and a passage extending around the valve seat and opening onto one of said insert surfaces to communicate with said rabbet apertures for the flow of cooling water therethrough.