Patent ID: 7032559

Claim:
An intake-port forming sand core, for forming an intake port of a cylinder head, which is set in a casting mold for cast molding the cylinder head, the intake-port forming sand core comprising: a sand core body; and a partition plate, for the intake port of the cylinder head, which is preliminarily set in the sand core body and cast in during cast molding of the cylinder head to partition the intake port into a plurality of ports; wherein the partition plate includes: an intake-side distal end; a cylinder-side distal end; a partitioning section formed between the intake-side distal end and the cylinder-side distal end; a pair of side edges protruding outward from the partitioning section to be cast in by molten metal when the cast molding is performed; and wherein at least one of the intake-side distal end and the cylinder-side distal end of the partitioning plate includes an acute-angled end face to promote breaking in the sand core body; and wherein the sand core body includes a concave portion which is formed by reducing the thickness of a portion of the sand core body.