Never mind. I didn't realize that the 1275 PCV restricted the total
vacuum. (I should have figured it would, given the way it's plumbed,
but my figurer is overloaded of late...)
Definitely vented cap.
Chris Kotting wrote:
>
> 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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