Engine Valve Stem Seal Oil Seal

Different than other seals in the engine, valve stem seals play an important role in lubrication. Valve stem seals allow a controlled amount of oil to lubricate the valve stem as it moves in the valve guide. The amount of oil that passes by the valve stem seal must be precisely controlled. Too little oil causes stem and guide wear; too much oil causes carbon buildup leading to valve seat damage, decrease in volumetric efficiency, increased emissions, catalytic converter degradation and excessive oil consumption.

STEM SEAL DESIGNS

There are two basic stem seal designs - deflector and positive seals.

SWKS engineers analyze the OE design for every application. The OE design is tested and benchmarked. Based on the analysis, we determine the material used, considering the durometer (relative hardness) of the rubber, temperature requirements (both extreme heat and extreme cold), resistance to common oil types, tear-resistance and leak rate.

This type of analysis makes one thing clear, not all valve stem seals are created equal. Visually, a lower-quality seal may look very similar to a high-quality seal that’s appropriate for a given engine platform. However, a lower-quality seal with insufficient heat-resistance will harden and crack prematurely and will not work as intended.

Engine Valve Oil Seal

Valve Stem Seal

On some applications, the valve stem seals are interchangeable between the intake and exhaust valves and will look exactly the same. On applications which use different seals on the intake and exhaust valves, due to needing higher temperature material on the exhaust side or different design, the seals will be bagged and labeled appropriately.

 

For assistance, contact SWKS Kris@tjswks.com