On Thu, 17 Jul 2003 12:35:15 GMT, "Joe" wrote:

snip

Again, I ask a simple question. If the rings, on a properly broken in
engine seal well enough to keep molecularly small exhaust gases from
getting INTO the crankcase,

They don't "seal well enough to keep molecularly small exhaust gases from
getting into the crankcase" . Where do you think crankcase pressure comes
from?

From GM:
"If we could perfectly seal the combustion
chamber between piston and cylinder
wall, there would not be any appreciable
cylinder block pressure. But, in fact, while
piston rings attempt to do the job for us, in
the best applications they can seal only
about 95% or less of the pressure developed
in the combustion chamber. This
"blow-by", comprised mostly of unburned
mixture of air and fuel, needs to be managed
back into the intake stream for emissions
purposes."

http://service.gm.com/techlink/html_.../200103-en.pdf

at a pressure of approx. 100 p.s.i., how
in the HELL does something molecularly larger (oil) make it through
the same rings at a third of the pressure? How?


Very simple Asslicker, a piston goes down on the intake stroke, the
combustion chamber is now under a vacuum. At this time the crankcase is
ALWAYS under pressure. Couple this with oil rings that do not remove *all*
of the oil from the cylinder wall, nor provide a 100% effective seal, and
you get oil in the combustion chamber that will be burned/consumed once the
power stroke comes along.

Note that this isn't the *only* reason that oil gets past the rings but
since you are stuck (once again) on pressure differential as your reasoning
I thought I would post this (again).

What's really going to blow his mind is the fact that oil is getting
past the rings in one direction at the same time as combustion gas is
getting past the rings in the other direction. Of course, the oil is
burned shortly after it makes it's way past the upper ring, past the top
of the piston and is exposed to the full heat of combustion in the
cylinder.

Steve