Difference between revisions of "Poppet valve"

In the early days of engine building, the poppet valve was a major problem. Metallurgy was not what it is today, and the rapid opening and closing of the valves against the cylinder heads led to rapid wear. They would need to be re-ground every two years or so, in an expensive and time consuming process known as a ''[[valve job]]''. Adding tetra-ethyl lead to the petrol reduced this problem to some degree as the lead would coat the valve seats, in effect lubricating the metal.  Valve seats made of improved alloys such as stellite have generally made this problem disappear completely and made leaded fuel unnecessary.