> The only time oil and gas can meet is through either the valves or
> the rings (assuming the intake tract is working properly).  Assuming
> the valve seals are in good shape, that only leaves the rings.  The
> cylinder walls are lubricated by oil splashing and spraying on them
> and at the same time (almost) they are exposed to combustion chamber
> gasses.  I would guess that the amount of gasoline and additives that
> ends up in the oil is directly proportional to the sealing capability
> of the rings.  I would expect that an engine with worn rings would
> dirty its oil almost immediately.  Has anyone experienced this?
> 
> -David

No, but looking at it the other way, take a look at your spark plugs on an 
engine with worn rings. Yechh!

I also think worn valve guides could be a source of oil/gas mix problems.

-Erik.

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