Umbrella Seals are one of the older valve seal designs. Popular since the 50's & 60's, these seals are simple yet effective for moderate oil control. Umbrellas will not "dry up" the guides. They function as their name implies, as small umbrellas which shield oil from traveling straight down the valve stem. Most OEM's phased out umbrella seals in the late 80's in favor of the positive seals which they still use today. Their main motivation to moving to positive seals was to meet Federal smog standards otherwise some of them might still be using them.
Umbrella seals simply cling to the valve and go up and down with the valve. Special machining is not normally required to use them.
Fitment requirements.
Performance engines running dual coil springs with small inside diameters normally will not accept an umbrella seal. The seals inside diameter needs to be big enough to go over the guide boss without touching the guide.
Umbrella seals come is several rubber materials, most which are black in color. Early seals were made from low tem materials which would hardened and eventually break apart. When the seals break apart, two problems arise.
Modern seal materials have come a long way.
The most common rubber polymer materials in use today are:
Nitrile is the same basic material used by the OEM's in the 60's. These are the seals which normally come in low cost gasket sets.
Nitrile and Poly Acrylic were used in the 70's and 80's.
Poly Acrylic seals are a better choice and are available at a reasonable cost
Floroelastomer (Viton) is the premium choice and come at a premium price. Large umbrella seals which require a lot of material to manufacture can be a little pricey.
Alex's Parts offers all three seal materials but only offer Nitrile seals in bags of 100. Poly Acrylic and Viton seals are available in sets of eight, twelve and sixteen as well as 100.
If you're looking for something specific, feel free to send us a message. We carry a lot of different seals, many which are not advertised on our site.
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