Die cast closed deck engine block manufacture

A method for making an internal combustion engine block, comprising:

• bringing a metal first die segment and a metal second die segment together to at least partially define a mold cavity shaped as said internal combustion engine block,
• said first die segment having a plurality of cylindrical projections and a plurality of die core pieces disposed about said cylindrical projections in spaced relation to each other and in spaced relation to said cylindrical projections;
• said second die segment having a plurality of die core stubs positioned so as to extend between adjacent said die core pieces when said first die segment and said second die segment are brought together;
• introducing melt to said mold cavity and allowing said melt to solidify to form an unworked engine block;
• separating said first die segment and said second die segment to release said unworked engine block;
• said unworked engine block having a plurality of cylindrical bores extending from a deck of said unworked engine block, said cylindrical bores formed by said cylindrical projections, a plurality of at least partially separated voids extending from said deck and disposed about said cylindrical bores, said voids formed by said die core pieces, said voids comprising segments of a water jacket, and a plurality of blind holes extending into sides of said unworked engine block, each blind hole having a blind end and extending between two said voids of a pair of adjacent said voids, said blind holes formed by said die core stubs;
• working said unworked engine block below the level of said deck by inserting a tool along a depth direction and into said each blind hole and cutting into said engine block at said blind end of said each blind hole in a direction transverse to the depth direction such that said each blind hole has a greater dimension in the direction transverse of the depth direction at said blind end than in the direction transverse to the depth direction at a mouth of said each blind hole, whereby said working undercuts a wall defining said each blind hole at said each blind end and forms an interconnected water jacket about said cylindrical bores while leaving said deck closed to thereby form said internal combustion engine block.