Over the years, valve heads have come in all sizes and shapes. There has been everything from domed heads to flat heads to cupped heads. There have been many contours including different angles and radii on these domes and the same on the cups. Presumably, they all made sense to the designer at the time.
In my experience, the main justification for dome shapes was to resist the combustion pressure by stopping the head from deflecting as much. On the contrary, the cupped head designs took advantage of that combustion pressure to assist in the sealing of the valve at the seat face. At one time, they were called "flexible head valves." They were designed with the head and cup angles diverging from one another at a rate of from 3
Latest posts by Ted Tunnecliffe (see all)
- Knock-Knock, Who’s There?…Detonation and Pre-ignition - Nov 1, 2001
- Valve Failure clues: Read ‘Em and Weep - Aug 1, 2001
- How to Make a Valve - Apr 1, 2001