Description
A valve stem seal (VSS) is the seal assembled in the engine head together with the valve guide, preventing the engine oil from flowing into the engine head combustor. Valve stem seals must be both leak-proof and permeable at the same time. The reason for this apparent contradiction is through controlled leakage. The valve stem seal allows a carefully defined amount of engine oil from the cylinderhead into the combustion chamber allowing a necessary lubrication of the rotating valve stem in the valve guide.
Application
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Materials
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