Thanks for all the info guy's. I know this has been discussed before but I
can never remember.
I should have posted this info in my original message.
The PCV hookup is going to be a tube from the timing cover connected to a
tube from the valve cover routed into the intake manifold through a stock
1275 Spridget PCV.
Larry Miller
----- Original Message -----
From "Chris Kotting" <ckotting at iwaynet.net>
To: "wizardz" <wizardz@maxinter.net>
Cc: "Larry & Sandi Miller" <millerls@ado13.com>; <spridgets@autox.team.net>
Sent: Monday, January 24, 2000 7:46 AM
Subject: Re: PCV - to vent or not to vent!
> Paul -
>
> I was under the impression that Larry was using a Weber set-up, where
> the vent line goes to a fitting on the air cleaner, rather than the carb
> itself. Since the air cleaner fitting generates much less vacuum than
> the carb fitting, I would still use a non-vented cap. Otherwise, ite
> seems to me that there wouldn't be enough vacuum in the crankcase to
> keep the car from piddling in the driveway. <grin>
>
> I used to run a Fiat X-1/9 that has a similar set-up from the factory
> (downdraught Weber, PCV plumbed to the air cleaner) that ran a
> non-vented cap.
>
> Chris
>
> wizardz wrote:
> >
> > hmmm.... I think a bit of clarification is in order here.
> >
> > Yes...as Chris reiterated, the whole point is to keep a slight
> > vacuum on the crankcase (lower end) . This helps to keep the oil
> > inside the crank and not leaking out through the rear crank journal
> > AS WELL AS to recirrculate blow-by gases to be burned in the intake.
> >
> > Depending on model year, some breather systems use a carbon
> > canister that also vents the gas tank and the valve cover
> > (via a restrictive orifice).
> >
> > The timing chain cover breather (lower end) either went through
> > a PCV valve directly into the top of the intake manifold, or was
> > routed via a Y pipe directly into the side of the carbs.
> >
> > This carb side port is 'ported vacuum' that is to say it's on the
> > 'atmospheric' side of the throttle plate. The high vacuum is only
> > applied if and when the throttle is opened. Even then, the port
> > (usually plumbed with something like a 1/4" diameter hose)
> > still only breathes through a small diameter restrictor hole into
> > the carb throat.
> >
> > Early models without the carbon canister, or vent pipe on the
> > rocker cover, used the PCV valve to the manifold with 'vented' cap.
> > Remember, you're pulling only a slight vacuum, you don't want full
> > manifold vacuum in the crank. The idea was to also pull
> > piston ring blow-by gases back into the intake to reduce acidic
> > build up in the oiling systems.
> >
> > Later models using the Y pipe to the carbs, the carbon canister,
> > and having the breather pipe on the rocker cover used a non-vented cap.
> >
> > Paul Tegler wizardz@toad.net http://www.teglerizer.com
> > OBie - '73 BGT - daily driver
> > http://www.teglerizer.com/mgstuff/ob_description.htm
> > Punkin' - '78 Spitfire - corner ripping screamer
> > http://www.teglerizer.com/triumphstuff/spit78.htm
> > Lil' Greenee - '73 RWA Midget - lady killer
> > http://www.teglerizer.com/midgetstuff/index.html
> >
> > Paul Tegler wizardz@toad.net http://www.teglerizer.com
> > OBie - '73 BGT - daily driver
> > http://www.teglerizer.com/mgstuff/ob_description.htm
> > Punkin' - '78 Spitfire - corner ripping screamer
> > http://www.teglerizer.com/triumphstuff/spit78.htm
> > Lil' Greenee - '73 RWA Midget - lady killer
> > http://www.teglerizer.com/midgetstuff/index.html
> >
> > -----Original Message-----
> > From: Chris Kotting <ckotting@iwaynet.net>
> > To: Larry & Sandi Miller <millerls@ado13.com>
> > Cc: spridgets@autox.team.net <spridgets@autox.team.net>
> > Date: Monday, January 24, 2000 8:09 AM
> > Subject: Re: PCV
> >
> > NON-vented. Regardless of how you plumb it, a vented cap will render
> > the PCV ineffective. (The function of a PCV system is to keep the
> > crankcase at slightly less than atmospheric pressure, a vented cap keeps
> > the crankcase at atmospheric pressure.)
> >
> > Chris Kotting
> > ckotting@iwaynet.net
> >
> > Larry & Sandi Miller wrote:
> > >
> > > I'm installing a PCV on the 1275 this week.
> > >
> > > Should I use a vented or non-vented cap?
> > >
> > > Larry Miller
>
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