Crankcase and main bearing cap construction

摘要

A method for manufacturing an engine includes the steps of: casting a side skirt having first and second opposing sidewalls and casting a transverse wall of the cast material connecting the sidewalls. The transverse wall will form a bulkhead and a main bearing cap. A first void and a second void are cast into the transverse wall on opposite lateral sides of a main bearing journal location, each void adjacent to one of the sidewalls. A main bearing journal hole is then machined into the transverse wall. Cast material is removed along a first removal path from the edge of the transverse wall and ending into the first void, and along a second removal path from the edge of the transverse wall and ending into the second void. A tool exerts an opening force within the circular bore to fracture the cast material along the first and second fracture planes to separate the main bearing cap from the bulkhead. Before fracturing the cast material along the first and second fracture planes, main bearing bolt holes and cross bolt holes can be machined into the bulkhead and the bearing cap. A spacer piece can be fit into the removal paths when reassembling the bearing cap to the bulkhead.