[Spridgets] addendum to Vizard on valve guide seals

Glen Byrns grbyrns at ucdavis.edu
Tue May 12 13:53:25 MDT 2009


While I agree with Vizard's logic for leaving valve stem seals off the exhaust
valves, there should be an addendum to the "Bible" that INSISTS on exhaust
valve guide seals on turbocharged engines.  The residual speed of the turbine
after the throttle is shut leads to strong vacuum in the exhaust manifold that
will suck oil BADLY.  While the neighbors have been understanding and
appreciative of the reduced mosquito count in the neighborhood, I'm pulling
the head off next weekend to put them on.  Without the exhaust tie-in of a
turbo, a supercharger should be fine without the seals.

Glen


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