Rich---I'll take a shot at answering your concerns about which is
causing the "blue smoke"..."worn guides or a faulty oil ring at #2
piston."
Do you believe #2 to have a bad oil ring because of a wet, oily
sparkplug? If not, why would you suspect only this cylinder to be
passing oil?
Manifold vacuum is not just a number generated from engine rpms. It gets
highest when there is rpm and the throttle plates are at or near their
closed positions, so it could be at any speed.
i.e. you could have a reading of 20 inches at idle or at 4,000 rpm,
(under light load).
More rpm sends more oil to the valve guide area, so there is a better
chance of getting more sucked down some of the guides.
You should see even more blue smoke out the tail pipes when
decelerating, from high engine speed. This is when the vacuum will be at
it's highest and pull the most oil past the guides. This should also be
when the combustion forces are lower in the crankcase, and less likely
to find their way thru the exhaust valves.
Dick
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