PURPOSE: To restrain the instrusion of molten metal between a die and a cylinder liner and to prevent the shift of the axis of the liner by forming a small diameter part for forming a molten metal pool part through a step part at the tip part of a bore pin formed to a little smaller diameter than the inner diameter of the cylinder liner to fit and hold the cylinder liner.

CONSTITUTION: The cylinder liner L is fitted to the bore pin 6 of a movable die 5 and successively, the movable die 5 is joined to a fixing die 5 so as to insert the cylinder liner L into a cylinder forming part surrounded with slide cores 3, 3 at the right and the left sides. Thereafter, the molten metal of Al, etc., is poured into a cavity 11 formed among these dies and cores from a gate 4. Then, a part of the molten metal is flowed in the blind alley-like molten metal pool part 7 formed between the small diameter part 9 at the tip part of the bore pin 1 and the inner peripheral surface of the cylinder liner L. The molten metal is difficult to flow into a gap δ between the bore pin 6 and the cylinder liner L by a vortex developed at the pool part 7, and further, the tip part of the bore pin 6 is expanded to narrow the gap δ, and the intrusion of the molten metal is prevented.