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Re: PCV Valve

To: Dean Swanson <d.swanson@earthlink.net>, spridgets@autox.team.net
Subject: Re: PCV Valve
From: "Robert E. Shlafer" <pilotrob@webtv.net>
Date: Sun, 04 Mar 2007 11:07:48 GMT
Either will do the trick, Dean, in terms of crankcase evacuation/pressure 
(prevents
oil leaks, too).

Both inlet and outlet sides of the both PCV systems are "graduated orifices" or 
specifically sized holes.

The early flying saucer intake-manifold mounted PCV valve used the plastic 
filtered oil filler cap as the crankcase air inlet.

Later cars with the carb PCV ports used a
feed from the carbon cannister (fuel system) to a valve cover "takeoff".

Either specific-sized inlet port can be used with either specific-sized outlet 
port.

One thing about some of the PCV-tube equipped SU's.....some later cars also had 
 
SU's with poppet-valves incorporated 
in their butterflies (which allowed extra air
into the intake manifold to clean up combustion emissions under deceleration) 
along with "spring-loaded" needles.

You don't want these, IMHO. 

You want the earlier less "maintenance intensive" PCV-tube equipped models with 
plain butterflies and "fixed"needles. These also are better for driveability 
(IMHO) as without poppet valves, revs drop much
faster on deceleration for "more" and 
more instantaneous compression (engine) braking. Otherwise it takes years for 
the
revs to drop off and brake wear increases
accordingly.

Cap'n. Bob      '60 :{)




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