Machining the connecting surface between cylinder head and block - by using two stages with intermediate heat treatment to prestress surface and thereby avoid distortion during actual working of engine

摘要

A cylinder head in a multicylinder (pref. water cooled combustion engine) is subjected to two machining processes to produce a flat connecting surface with the cylinder block with an intermediate heat treatment in the area between the valve inlet and outlet opening(s). ADVANTAGE - The heat treatment causes tensile stresses to be formed in the surface layer which during working of the engine are released and form small pressure stresses which do not lead to surface distortion. The joint between cylinder head and block remains flat and sealed.