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PCV Valve summary

To: <healeys@autox.team.net>
Subject: PCV Valve summary
From: "Bluechipracing" <bluechipracing@snet.net>
Date: Sun, 20 Mar 2005 17:25:13 -0500
Here is the info I received in reply to my query about PCV valves....

>From Michael Oritt
I have one of those finned valve covers with a sealed oil filer cap--I drilled
and tapped a hole in the left side and threaded in a brass barbed fitting for
3/8" or so ID hose--the hose goes onto the nipple on the CAB.  I suppose you
could do the same thing connecting onto one of those aircleaners with a nipple
on it to provide the suction to negatively vent the crankcase.
That said, nothing prevents oil leaks like a real oil seal  as opposed to the
stock set up.

>From Steve Gerow via Ken Freese:
The vacuum fitting for the manifold was the hardest to find. The one I
bought (Autozone) is a 3/8" IF to 3/8" hose, fuel line fitting. Don't ask me
what IF means, I'm just copying this off the bubblepack. It is definitely
not a 3/8" pipe thread (it's not tapered). The one I bought didn't have a
gasket surface on it, so I used Hylomar on the threads.
There seem to be a lot of inline PCVs that will work. Look for one with a
3/8" tubing fitting on one side and 1/2" on the other. There should be a
flat metal surface visible inside the 1/2" end--that means the other end is
the vacuum end, which goes toward the manifold. The 1/2" end goes toward the
tee in the valve cover. The rear air cleaner hose inlet then gets plugged.

>From Ed Driver:
Please find attached the photos I mentioned; the valve I used was obtained at
NAPA, the valve type was classified as PCV Type 1 metering CV727C.  If you
can not  find one let me know, I'll pick one up and send it to you.
I can say that this has reduced the oil leaking and to somewhat marginally
improved
the performance at idle.

>From Bob Spidell
Mighta been me (among others).  I fitted a PCV valve when I put K&N filters on
my BJ8
(see attached photo).  I got the "kit" from British Car Specialists ... it's
just a std. PCV valve,
some hose, a fitting for the manifold and a grommet to seal the dipstick tube.
I had to tap the
(usually) plugged boss on the manifold to NPT (1/8", if I recall) to fit the
brass hose adapter.
I had to "step down" the hose from the valve cover "T" ... I used a plastic
heater hose adapter
from a local parts house.
Norm's "design" is to seal the dipstick tube and the hole in the filler cap,
creating a (relatively)
closed system (a normal PCV system will pull filtered air into the valve cover
and suck it
out of the crankcase, this one just sucks ;).
Presumably, the "closed" system helps stop oil from leaking out the rear main,
though I haven't seen
this to be the case.  However, I was getting quite a bit of blue smoke after a
long downhill, closed-throttle
run, and this seems to have diminished significantly.
The RPM went up 100 or so when I first installed the valve.  I attribute this
to the small air
"leak" caused by the PCV valve.  The RPM has since stabilized at about the
original setting.
I enrichened the rear carb a little.
So far, I am quite happy with this setup, especially the K&Ns ;)  I only have
a few hundred
miles on it, but don't expect any problems.

>From Norman Nock
Jim...   lf you have my Tech Talk book check page 98 ... CAUTION . if your
rockers are worn you could start to burn oil ...

Also I got a little help on the archives.....Thanks Ed and -pd-

Plus several additional referrals to to the Tech Talk
http://www.britishcarspecialists.com/tech-tmpl.html

Thanks to all.

Jim




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