Just walked in to this discussion.
Does all this mean that I should re-plumb the vacuum
on my '72 1275 with SUs? My vacuum also runs off the
manifold. Is tehre a way to take it off the carbs?
Haynes, Mark wrote:
> Manifold vacuum decreases as your throttle plate opens. The dizzy wants full
> advance at full throttle. if you use carb vacuum,the dizzy gets an
> appropriate indication of the engines running demands otherwise, you get
> less advance at full throttle, and more at idle . just the reverse of what
> you relly want.
> Mark Haynes
> '62 Sprite XSP motor
> > -----Original Message-----
> > From: Richard Shipman [SMTP:email@example.com]
> > Sent: Wednesday, August 04, 1999 7:28 AM
> > To: John MacDonald
> > Cc: firstname.lastname@example.org
> > Subject: Re: Timing the 1275 ? (vac. advance with a sidedraft)
> > I don't understand... If the vacuum advance on my '74 Midget works with
> > manifold vacuum, why won't manifold vacuum work with other
> > configurations??
> > Richard
> > '74 Midget
> > '68 MGBGT
> > '58 Morris Minor
> > >Variable vacuum. At the manifold it is 100% vacuum providing 100%
> > advance
> > >all the time. Just before the throttle plate it is variable.
> > >
> > >>Can anyone explain to me why my '74 Midget with SU's has a simple vacuum
> > >>advance fitting right on top of the intake manifold and yet so much care
> > >and
> > >>attention is being taken to locate the vacuum pick-up at a specific
> > point
> > >on
> > >>a sidedraft weber??
> > >>
> > >>What am I missing??
> > >>