Cap'n,
That is an interesting and comprehensive description of your (car's)
pcv system.
Just wondering why it is necessary to extract from the fuel-pump
monting plate position as well as the timing gear cover? Don't they
both in effect draw pressure from the same space - i.e. the crankcase?
What's the advantage of the dual system?
Guy
PS - serious this time Bob, - honest - no catches here!!
----- Original Message -----
From "Robert E. Shlafer" <PilotRob at webtv.net>
To: "Phil Profili" <Phil.Profili@cptii.com>
Cc: <BlkBT7@aol.com>; <spridgets@autox.team.net>
Sent: 10 May 2002 03:14
Subject: RE: Rear Main Seals
> As far as an engine PCV set-up, yes.
>
> It is designed to run with an otherwise
> closed crankcase with the possible
> exception of a small hole in the filtered
> oil filler cap, as specified (or not) for the
> original application.
>
> The above having been said, the otherwise "vented" (through
breathers -
> no PCV system)
> crankcase is a purely "open" system.
>
> My new Rivergate engine is "open
> crankcase". It has no PCV system.
> It has a 1/2" breather on the valve
> cover and another 3/4" breather fabricated
> over the hole used by the old mechanical
> fuel pump. It has the Rivergate rear engine plate incorporating a
real
> oil seal.
>
> It is a tuned 1293 "tailored" for low pressure supercharging
(Judson)
> running
> a static CR of 8.3-1 (aluminum head).
> The engine has just done 500 miles and
> is now being pushed to 4,500rpm every
> now and then....it still has a tendency
> to run on the warm side (not fully broken
> in as yet) but, absolutely no oil leaks thus
> far; absolutely none.
>
> The oil filler cap also has a small,
> calibrated orifice.
>
> All "holes" for beathing are filtered, including the calibrated hole
in
> the oil
> filler cap.
>
> The PCV set-up (a la '67 timing case
> cover to intake manifold through diaphragm equipped "valve") works
> best. The carbs are out of the PCV
> "loop" (unlike later emissions applications)
> and are thus, spared contamination by
> crankcase gasses. The crankcase
> vapors are literally "sucked" out of the
> crankcase through "calibrated orifices"
> into the intake manifold to be equally
> distributed to all cylinders in proportions
> that are cleanly combustible. Crankase
> pressure (against oil seals) is minimized
> accordingly.
>
> This particular "early" PCV set-up is
> a "friend" of the engine, unlike later
> set-ups which contaminated the carbs.
> with all sorts of crankcase vapor "junk",
> eventually "gumming up" their works. Of
> course, the priority at this point was
> cleaner air through more complete
> combustion, not performance or even
> economy.
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