How must the surface finish of a cylinder head be for proper gasket sealing?

The proper surface finish of a cylinder head is critical for ensuring effective gasket sealing, which is essential for maintaining engine performance and preventing leaks. The surface finish must be compatible with the specific type of head gasket being used. Different gaskets, such as graphite, composite, or metal, have varying requirements for surface texture and finish.

When a gasket is installed, it deforms slightly to fill any imperfections in the surface of the head. A finish that does not match the gasket's needs can lead to insufficient sealing, resulting in leaks and potential engine damage. For example, some gaskets require a smoother surface to create a tight seal, while others with higher surface roughness can fill voids better. Therefore, ensuring that the cylinder head's surface finish aligns with the type of gasket used is critical for the integrity of the engine assembly.