Sandy Hutton
One couldn't dispute that crank case pressure increases with gas blow by.
Is this evidence of increased blow by when compression ring gaps line up?
Good point about two stroke engines, can be also found on two stroke diesel engines with normal valve train.
You may find that oil consumption through the valve guides is a consequence of worn valve guides without the need for increased crank case pressure.
That is interesting about the manometer pressure for the crank case, have you ever checked your engines? I can't recall seeing it done. Where do you connect the tube to? Crank case breather?
Blackhand