Inlet port flat wall section

摘要

A cylinder head for an internal combustion engine of the reciprocating piston type includes a helical inlet port with a flat wall portion in a section of the port upstream of a bowl-shaped recess about a valve stem guide. The flat walled section meets a generally cylindrical portion of the recess adjacent a cusp-shaped swirl edge. The orientation of the flat portion with respect to a reference feature, such as the axis of the valve stem guide, may then be used as a measure of the accuracy of casting of the inlet port, and may also be altered if so desired to vary the swirl characteristics of the inlet port.