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Subject: PCV
From: Richard Lancaster <>
Date: Mon, 07 Oct 1996 13:37:32 -0400
I also have a 67 B, and rattled on about this almost a year ago.  
The thing is supposed to bring up the vapors from inside the engine
and burn them thru the intake to prevent those vapors from getting
into the atmosphere.  
Now, several things must work for that to happen.  First, if your
line comes off the front inspection plate, that plate should have a
trap filled with something (wire?) to stop most of the oil vapors
from being sucked up.  Second, the PCV has a very thin rubber
diaphram in it.  If you don't get it installed just right or it has a
small hole, its busted.  And the metal springy cover over it must be
lined up with the snap wire holder that keeps pressure on the top
over the rubber.  

The PCV has a metering section to it, that reduces the size of the
hole before it goes into the input manifold.  If its been rounded out
or broken out by someone, then it draws too much air and gets oil up
there.  Finally, or first actually, the oil filler cap MUST be vented
with this setup...that is where the atmospheric or clean air is drawn
into the engine by the vacuum created at the inspection plate....and
the process continues.  (See Moss catalog for the three different
types of oil filler caps.)

Check the oil filler cap has a small side hole and a small
filter (cotton fibers?) built into it, and if the hole is blocked or
someone gives you a non-vented cap, that is your problem.  Also, the
thing does NOT suck vapors up at idle, or it would probably stall
out, the rubber seal in the PCV only opens up at higher pull or
vacuum when above an idle.  And to see if its working at all right,
take off the oil filler cap at idle, and put your hand over the
filler cap.  It should suck on your hand a bit and almost stall, or
stall out.  If it is doing that, at least you know that the basic
flow is right...good luck!!!
||Randy Lancaster               | Tel:202-482-4487        ||
||National Telecommunications   | Fax:202-482-4396        ||
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||Department of Commerce, USA   | 1967 MGB # 128,471      ||
||Heaven: home brew, driving an MG, but remember...its not||
||a leak, its a British flow through lubrication system!  ||

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