Paul -
Non vented, with him hooking up to manifold vacuum without a
restrictor? Are you sure? I'd have thought vented, otherwise you'd be
pulling a LOT of vacuum.
Chris K.
wizardz wrote:
>
> AAhh... much better...definitely non-vented.
>
> 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: Larry & Sandi Miller <millerls@ado13.com>
> To: spridgets@autox.team.net <spridgets@autox.team.net>
> Date: Monday, January 24, 2000 11:49 AM
> Subject: Re: PCV - to vent or not to vent!
>
> 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@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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