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Hi Guys,

I have a question about valve guide seals (and i know the green viton seals are the preferred) which i cannot see mentioned before on this BB, apologies if i have missed it.

Now i know by using the seals adds some longevity to the valves, reduces the possibility of oil running down the guide and burning the valve etc, but what about lubrication ?

If there is no oil between the valve and the guide, wouldn't that increase friction and therefore reduce the life span of the valve guide and possibly cause the valve to cease in the guide ?

Or do the seals permit a very small amount of oil to pass through?

Thanks in advance for any help.

Rob.
 

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Valve Guides are usually manufactured from Phosphorus Bronze Alloy providing superior heat transfer, resistance to seizing and a lower friction coefficient. The valves of course are steel, thus little friction between the two materials. Thus, there is little need for what could be ordinarily regarded as adequate lubrication. In other words, not to worry.

The guides and valve stems do wear eventually, but not at a rate requiring even infrequent replacement. There might be only a slight amount of oil passing the guide seals, but that is enough to do the job for a long long time.

Examples:

My 91 164S has 172k miles on it now, and the guides and seals are still adequate as far as I can tell, the engine exhibiting no smoke problems which would indicate bad seals and/or guides. It does drink oil (w/no smoke) but Carlo (my guru) says that it is due to bad OEM oil rings which were evidently installed on certain 164s in 1990/91 (our 89 Milano w/105k miles and 94 LS w/110k miles use zero oil).

Our older 78 Alfetta sedan ended up with 180k miles on it when we sold it, with no rebuilding of the head, and it also had no smoke problems, nor did it use oil worth talking about. Ran just great. Now lives a nice life south of Boston.

Viton material is often used as a more petroleum resistance elastomer for seals and o-rings, ie, remaining more flexible for a longer time while subject to petroleum products and heat.
 
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