PURPOSE:To make a flow of melten metal into an upper peripheral wall so better and its wall thickness smaller, by installing a rib in an inner surface of the upper peripheral wall of a cylinder head, and extending this rib continuously in a range from an upper end of this upper peripheral wall to a cylinder head body at the base. CONSTITUTION:In an upper peripheral wall 1b of a cylinder head 1, there are provided with vertical ribs 19 and 20 arranging, ranging from an upper end of the upper peripheral wall 1b to each of bosses 14 and 15 for head bolt clamping, in an inner surface of a plane part at the longitudinal central part. Also in an inner surface of the upper peripheral wall 1b at the suction side, there is provided with a horizontal rib 21 connecting the said rib 19 and a cam holder clamping boss 10 at both sides of the rib. In addition, a tilting rib 22 is installed at the inner side of the cam holder clamping boss 10. On the other hand, in the inner surface of the upper peripheral wall 1b at the exhaust side, there is provided with a rib 23 extending from the top of a clamping boss 18 for exhaust manifold setting use to the upper end of the upper peripheral wall 1b. In addition, an interval between these ribs 20 and 23 is connected by a rib 24 extending in the horizontal direction.
展开▼
