Actually Dan, on the Spitfire engines, there is no PVC valve between the
valve cover and the end of the hose. The only thing that could be
interpreted as a PCV valve was on the Mk3 engine and it was built on top of
the intake manifold. So routing it to a catch bottle rather than to the
carb intake will not cause any back pressure in the crankcase.
To carry the issue even further, crankcase pressure can be further reduced
by installing a breather in the block and tying it into the same catch
bottle that you can use to capture any oil mist given off at the valve cover
breather. This is normally done at the fuel pump port when an electric fuel
pump is installed.
From: email@example.com [mailto:firstname.lastname@example.org]
On Behalf Of Dan Canaan
Sent: Friday, September 30, 2005 9:47 AM
To: James Catalan
Subject: Re: Hose to nowhere on valve cover
Crankcase breather / ventilation hose. It should go back to the carbs or
intake manifold depending on your setup. This is also the location of PCV
(Positive Crankcase Ventilation) valves. If you plug it, you could
pressurize the crankcase and you'll find you have oil leaks where you
never thought possible. Vented, it just relieves the pressure and vents a
bit of oily vapor. The best place is to route it back to your intake
where the vapor can be burned with the fuel.
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