Organic-like casting process for water jackets

A method of casting an engine component, comprising the steps of:

• forming hardened granules of a core material having a three-dimensional solid shape;
• applying a binder to the hardened granules;
• agglomerating a multiplicity of the granules in a master mold in a shape of a water jacket of the engine component and hardening the binder to form an organic-like core having a continuous web structure;
• forming a plurality of other cores in respective master molds to define respective surfaces of the engine component;
• assembling the organic-like core with the other cores to form a casting mold;
• casting the engine component by flowing molten metal into the casting mold, thereby forming a continuous parent metal bridging the water jacket having a predetermined porosity;
• and
• removing the core material from the engine component after casting;
• wherein the multiplicity of granules includes a group of smaller granules and a group of larger granules wherein the larger granules all have a maximum diameter greater than the maximum diameter of the smaller granules, and wherein the multiplicity of granules are agglomerated in the master mold with a highest concentration of larger granules in a center region of the organic-like core and a highest concentration of smaller granules in an edge region of the organic-like core.