Patent ID: 8181344

Claim:
A method of manufacturing an engine cylinder block, the method comprising: casting and machining the engine cylinder block as a single one-piece assembly to include: a pair of generally parallel longitudinally extending sidewalls defining a lower crankcase therebetween; a plurality of longitudinally spaced laterally extending web walls, each having an upper portion attached to the pair of sidewalls by a lateral connector, and a lower portion; a plurality of crankshaft bearing bores aligned on a crankshaft bore axis and extending through the lower portion of each of the web walls, wherein the crankshaft bore axis is disposed on a horizontal plane bisecting the crankshaft bearing bores and extending between the sidewalls, and wherein the lower crankcase extends upward beyond the horizontal plane; and a plurality of blend radii, with each blend radii connecting the upper portion of one of the web walls with one of the lateral connectors; and fracture-splitting a bearing cap from each of the web walls along a downwardly sloping fracture-split line initiated at opposite sides of the crankshaft bearing bores on the horizontal plane and extending downward at a predetermined angle to outer edges of the bearing caps disposed below the horizontal plane and wherein the radius of each of the blend radii is increased so that the blend radii extends from a location at the outer edge of the bearing cap disposed below the horizontal plane to the lateral connector disposed above the horizontal plane.