On Sun, 1 Jul 2007 04:40:39 -0400, "Stormin Mormon"
wrote:

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.

I see I'm lacking the point about the "down" stroke and that pressure
building up.

I've taken that for granted and the "real" purpose of the breather.

I seemed to have been stuck on "ventilation" and by that I mean, if
the engine was seriously flooded the gases would leak into the
crankcase breather chamber (open valve) and would be vented out this
breather. Say a valve was bent or a weak spring or a broken valve
seal; then these fumes/gases may leak into the chamber and be vented
outside. These are cases of engine damage, but where combustibles get
into the breather chamber.

I get the real purpose now... preventing pressure by ventilation :-)

Clear as mud? :-)) NOT!
--
Oren

"I don't have anything against work. I just figure, why deprive somebody who really loves it."