From what I understand, the major reason for a crankcase breather
is so that the pressure of the piston going "down" doesn't
pressurize the crankcase. The internal air pressure tends to blow
oil out any leaky seal, or gap in the gasket.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
..

"Oren" wrote in message
...
:
: And really it is. Especially in a motor that depends on motor
parts
: splashing the oil around from the sump instead of it being
pumped.
:
: If the valves seat tightly and seals - do not leak, there is
very
: little chance for oil to enter the chamber covered by the
breather.
:
: The breather wants to release gases, so they do not return to
the
: combustion chamber through a valve and or misfire and send a
puff of
: smoke out the exhaust.
: