Casting apparatus and casting method for producing cylinder block

A method for producing a closed deck type cylinder block having a top deck portion and a plurality of juxtaposedly aligned cylinder liners, a water jacket portion being formed around the cylinder liners and having one open end open at the top deck portion, the open end being partly closed by a plurality of bridge portions provided at the top deck portion, the method comprising the steps of:

• preparing a metal mold die fort molding a substantial part of the cylinder block, the metal mold die having a die portion whose profile is the same as that of the water jacket portion for forming the water jacket portion, the die portion having a free end portion formed with a plurality of notched portions each having side walls extending in an axial direction of the cylinder liner and a bottom wall provided with a projection;
• preparing a plurality of pairs of loose cores, each pair being insertable into each botched portion, and each pair of loose cores having symmetrical shape and having parting faces extendible in the axial direction of the cylinder liner, each pair of loose cores having a first draft facing the bottom wall of the notched portion and a second draft which defines a part of a lower end of the water jacket portion, and a distance between the first and second drafts in the axial direction of the cylinder liner being gradually increased toward opposite circumferential direction of the water Jacket portion from the parting faces;
• setting each pair of loose cores into each notched portion in such a manner that the parting faces extend in the axial direction of the cylinder liner and the end of the parting faces is placed on the projection of the bottom wall;
• injecting a molten metal into the metal mold die for forming the bridge portions at positions between the bottom wall of the notched portion and said first draft, a bore corresponding to the projection being formed in each bridge portion;
• inserting a jig into the bore and pressing the jig toward into the parting faces for moving the pair of loose cores away from each other from the parting faces, so that each pair of loose cores are offset from the bridge portion;
• and
• removing the thus separated loose cores from the open end of the water jacket portion.