Abstract: A method for forming a core includes the step of providing a corebox defining in a closed configuration thereof a closed internal core-forming cavity and providing at least one external opening through the corebox into said cavity in the closed configuration (902). A core release substance is applied through the opening directly onto at least one surface of the closed core-forming cavity with the corebox in the closed configuration (904). A forming material is added to the cavity (906) followed by an addition of a core bonding agent (908). A core that has formed in said closed core-forming cavity is allowed to dry and removed from the cavity (910).

Abstract: A block casting for an internal combustion engine and method of its manufacture provide reduced engine block size and weight, and/or increased engine displacement, through cylinder-forming walls that decrease in thickness from minimal explosion-resistant thicknesses at their combustion chamber ends to reduced thicknesses at their other ends.