Water jacket spacer

A water jacket spacer adjusting a flow amount of cooling water in a water jacket, the water jacket spacer being inserted into the water jacket of a cylinder block, the water jacket spacer comprising:

• a spacer body;
• and
• a rectification portion inhibiting flow of cooling water to an inner wall on a cylinder bore side of the water jacket, the rectification being provided on an outer face of the spacer body so as to project from the outer face of the spacer body to a cooling water introduction port side and being provided lower than the cooling water introduction port in a depth direction, the rectification portion having a front wall portion, a bottom wall portion, a right side wall portion, a left side wall portion, and an open upper end to form a box-like pocket, the bottom wall portion being formed so as to project from the outer face of the spacer body to the cooling water introduction port side, the right side wall portion and the left side wall portion being formed respectively so as to extend upward from right and left ends of the bottom wall, the front wall portion being connected to the bottom wall portion and the right and left side wall portions and being positioned so as to face the outer face of the spacer body,
• the water jacket spacer being assembled so as to have a gap on at least one side of the water jacket spacer, each gap being between the water jacket spacer and one of an inner wall portion and an outer wall portion of the water jacket.