Oil passage construction for die-cast formed product, and oil passage construction for internal combustion engine

摘要

The inner surface of an oil passage in a member which is made as a die-cast formed product is made as a molded surface. By this structure, permeation of oil from the inner surface of the oil passage into the thickness portion of the member which is made as a die-cast formed product, and leakage thereof out to the exterior, is prevented.