Valve Stem Seals - Enginetech

Enginetech Premium Positive seals are metal clad with high-temp Viton® elastomer sealing lips. All Premium Positive seals are designed to work with valve stems from 0.005" under to 0.015" over. Most of these seals can be used as a universal fit on normal guide sizes such as 0.482", 0.500", 0.512", 0.530", 0.562, 0.625" etc. Stem diameters range from 8.00mm to 3/8".

Enginetech Premium Umbrella seals are high-temp Silicone with garter springs to retain stem interference. All Premium Umbrella seals are designed to work with valve stems from 0.005" under to 0.015" over. Most of these seals can be used as a universal fit on normal stem sizes such as 8.00mm, 5/16, 11/32" and 3/8".

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I've never used these umbrella type valve stem seals. Do you install them with enough room on the stem to allow them to move up and down or the same way the OE seals tight to the bottom? And do the same umbrella seals work on both intake and exhaust stems?