PURPOSE: To effectively prevent between-valve crack on a cylinder head by casting a heat-resistive plate onto the surface contiguous to the combustion chamber in the cylinder head and extending said heat-resistive plate outside from the line connecting with the opened edge parts of an intake port and an exhaust port and allowing said heat-resistive plate to be exposed to the above-mentioned surface.
CONSTITUTION: A cylinder head 1 is equipped with an intake port 2 and an exhaust port 3, and the respective guide holes 4 and 5 for supporting an intake valve and an exhaust valve are formed on said ports 2 and 3, and valve seats 6 and 7 are mounted onto the opended edge parts on the undersurface sides of the ports 2 and 3. In this case, a heat-resistive plate 8 is incorporated between the opened edge parts of the ports 2 and 3. In other words, the heat-resistive plate 8 is casted integrally with the cylinder head 1 when it is casted, and the heat-resistive plate 1 is installed, projecting from the undersurface of the cylinder head 1, namely the surface contiguous to a combustion chamber. The top edge of the heat-resistive plate 8 is extended outside from the line connecting the peripheral edge parts of the opened parts of the ports 2 and 3. Thus, between valves crack on the cylinder head 1 can be effectively prevented by said heat- resistive plate 8.
SUZUKI TAKAYUKI
YUZURIHA MASATOMO
