Valve Stem Seals
The valve stem seal has three major functions: one is to prevent the mixture of gasoline and air and the exhaust gas from leaking,
the other is to prevent the oil from entering the combustion chamber; and 30 to prevent the oil from entering the gas pipe.
Leak-proof performance to meet the lubrication between the valve guide and the guide sleeve,
and supply a small amount of lubricating oil, while preventing excessive oil from entering the gas chamber,
so it has a preventive ability to control the amount of oil.