« Previous Entry | MAIN | Next Entry »
December 28, 2003
BECKERS states (in part)..
"....it lowers fuel octane anyway"
Yeah, this is true and a tough one to call (except in a high compression
motor or
when higher octanes are available at
reasonable cost) against crankcase
evacuation of vapors/pressures with
respect to oil being forced passed
seals or out the rear scroll "seal".
But it's basically why I run "vented" instead of "evacuated", the
thought
of introducing oil (in any amount)
into the combustion process "going against the grain" personally, though
there are cases (Judson and to a lesser
extent, Shorrocks applications) where this comes with the territory so
to speak.
Introducing oil into the combustion process also lowers the combustion
temperature. This oil also acts as a
lubricant to the exhaust valve tract
as well. However, oil in the combustion
process is also a "carbon builder".....
always "compromises" and thus, priorities
rule.
So there are "offsetting" benefits
to crankcase evacuation. In a more or less stock compression set-up
wherein octane
is not a major priority it works well...in
a high compression set up wherein power is definitely a priority, oil
within the
combustion process is anethma and
tubes off vents (as many vents as possible!) to a catch can are the way
to go, no doubt about it, and is what I
run for the road, anyway. The one exception to the foregoing was my
'64 MGB with it's '67 5 main bearing
motor running the "flying saucer" intake
manifold mounted PCV valve with
filtered oil filler cap. Worked well.
Yet, I have come to believe for the stock
motor, that crankcase evacuation
is probably more of a good idea
than a bad one, assuming the inlet tract
gets an annual cleansing with carb cleaner along with a steam cleaning
of
the combustion chamber by the introduction of water sprayed through the
carbs at a couple of thousand rpm, to remove "crud" and reduce carbon
build-up
to one extent or another.
If I "had to" by law, then
the early system with the "flying saucer"
PCV valve on the inlet manifold in
conjunction with the filtered cap is personally preferred. The later
system
which includes the carbs makes me
barf for this reason alone, not to mention
the power robbing "air pump" (yeeech).
I'm neutral on the charcoal cannister bit
as long as I don't have to think about it.
But on the whole, I agree with Becker's...
....I am a believer in the KISS principle...
running well vented into a catch can works for me personally...always
has,
still does, and always will.
Have a Happy New Year "down there",
guys. It's summer, after all! Wish I was
there and you were here (freezing YOUR
a$$ off!:).
Cap'n. Bob
'60 :{)
PilotRob@... 27891
Posted on December 28, 2003 08:07 AM
Posted to category(s) Carburetor | Cooling System | Cylinder Head | Engine (external) | Engine (internal) | Exhaust System | Fuel System | Gauges | Intake System | Lubrication System | Miscellaneous | Restoration | Technical Info | Tuning
