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RE: Tach drive

To: "Sprites (E-mail)" <spridgets@autox.team.net>
Subject: RE: Tach drive
From: "Webster, David" <David.Webster@smec.com.au>
Date: Thu, 21 Oct 1999 09:50:50 +1000
Reply-to: "Webster, David" <David.Webster@smec.com.au>
Sender: owner-spridgets@autox.team.net
Sorry to butt in, but I wanted to point out that you need a pulley with 4x
the circumference, not 4x the diameter. That means you'll need an 8" dia.
pulley - not 16.

by the way - what exactly is a 'jackshaft'?

Dave Webster

64 sprite
58 Holden (GM)
64 Vespa

-----Original Message-----
From: Ron Soave [mailto:soavero@yahoo.com]
Sent: Thursday, October 21, 1999 6:05 AM
To: Chris Kotting
Cc: Hanna, Mark; 'spridgets@autox.team.net'
Subject: Re: Tach drive


probably why they used gears, huh?

--- Chris Kotting <ckotting@iwaynet.net> wrote:
> Pardon the interruption, but I think you may run
> into a problem with
> this plan:
> 
> If the generator turns 4x for every turn of the
> tachometer cable, then
> to get the same effect via a direct drive off of the
> belt with a
> jackshaft, that pulley would have to be 4x the size
> of the generator
> pulley.  
> 
> A jackshaft pulley >>smaller<< than the generator
> would give a
> rotational speed >>faster<< than the generator.
> 
> The generator pulley is, what, about 4 inches?  You
> got room under there
> for a 16" jackshaft pulley?
> 
> Chris Kotting
> ckotting@iwaynet.net
> 
> Ron Soave wrote:
> > 
> > That would be a nice solution.  The reduction
> ratio in
> > the gearbox is 4:1, the generator output shaft
> turns 4
> > times for every one turn of the tach cable.
> > 
> > --- "Hanna, Mark" <mhanna@ball.com> wrote:
> > > Hi Ron ,
> > > My car will have an alternator. I would like to
> use
> > > the stock Bugeye tach. I
> > > was thinking of driving the tach directly from a
> > > jack shaft attached to an
> > > appropriately sized pulley.  Say 1/3rd the
> diameter
> > > of the main crank
> > > pulley. This way I would not need a gear box. Or
> do
> > > I have this backwards ,
> > > i.e. the tach has to turn 3 times as fast as the
> > > crank ? I haven't spent any
> > > time on the problem yet. I will be very
> interested
> > > in what you come up with
> > > .
> > > Mark Hanna
> > > AN5
> > >
> > > > -----Original Message-----
> > > > From:       Ron Soave [SMTP:soavero@yahoo.com]
> > > > Sent:       Wednesday, October 20, 1999 9:58
> AM
> > > > To: spridgets@autox.team.net
> > > > Subject:    Tach drive
> > > >
> > > > List,
> > > > I have been working with a machinist in town
> to
> > > try to
> > > > come up with gears to replace those in a
> generator
> > > > tach reduction gearbox (it a 4:1 ratio).  What
> we
> > > are
> > > > trying to do is find spur gears from, say,
> Berg or
> > > > Boston Gear, that can be modified to work. 
> Has
> > > anyone
> > > > done this research before?
> > > >
> > > > This was spurred by a failure of my gearbox. 
> The
> > > box
> > > > is an aftermarket item from "a major LBC part
> > > > distrbutor" (begins with M, rhymes with
> "Toss")
> > > with
> > > > potmetal gears.  Several teeth just kind of
> > > sheared
> > > > off, and the machinist said the quality of the
> > > metal
> > > > on the gears was "expletive deleted."  The
> > > machinist
> > > > basically felt the entire box could be
> hand-made
> > > with
> > > > high quality for what the aftermarket places
> > > charge.
> > > > If this ends up being the case, you'll be the
> > > first to
> > > > know.
> > > >
> > > >
> > > > =====
> > > > Ron Soave
> > > > "You Are What You Remember"
> > > > 1960 Bugeye
> > > > 1972 BGT
> > >
> > 
> > =====
> > Ron Soave
> > "You Are What You Remember"
> > 1960 Bugeye
> > 1972 BGT
> 


=====
Ron Soave
"You Are What You Remember"
1960 Bugeye
1972 BGT

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