[AMC-list] Valve seals

["Bruce Hevner" <scramblr@xxxxxxxxxxx>]

>One would have suspected intake seals as they are the ones under vacuum but
changing them didn't help. The exhaust seals, which probably run hotter,
were no >longer working right. Runs great now.

 

 Actually the exhaust seals are under vacuum too. As the exhaust exits the
port and the valve closes the pulse moving down the port creates a vacuum
which will suck oil down the guide. And of course the exh valve guide runs
hotter which causes those seals to go bad sooner.

 This is an area where a LOT of racers go wrong. Not using seals on the
exhaust valves can make the valves go bad SOONER! Too much oil causes a
buildup of carbon right at the end of the guide. As the carbon gets thicker
it can actually cause the valve to "stick" enough to prevent it from seating
and results in the valve burning. I have seen this MANY times from the use
of those JUNK white "Teflon" seals!! They are a "square" lipped seal and do
little to nothing as far as sealing goes. The ONLY reason for using them is
if the inner spring prevents anything bigger from fitting.

A good way to tell if you're having this problem is to look inside the exh
port and see if there's an oil "trail" coming from the end of the guide and
flowing down the port.

It's always been amazing to me how little oil the exhaust valves really
require for proper operation!!!

But HEY,,, that's just ME!!!

Bruce Hevner

 

 

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