Spring damper with controlled wear area

摘要

An internal type, spring damper for use in an internal combustion engine or the like having a cylinder head with a poppet valve supported for movement between valve open and valve closed positions and with a coiled valve return spring loosely encircling the stem of the valve and operatively associated at one end with the valve and having its bottom end operatively in abutment with the cylinder head whereby to normally bias the poppet valve to the closed position, has at least its corresponding bottom end of reduced external diameter for a predetermined axial extent whereby to eliminate damper-to-spring contact for up to at least 11/2 coils of the valve spring at its bottom end.