tech: engine balancing - why dont our engines have balancer shafts?

[roccolister@hotmail.com (Craig Williams)]

AFAIK,

A balancing shaft is purely to make the engine feel smooth in the cpassanger 
compartment. My Saab has 2 counter-balance shafts spinning off of the cam 
belt, and yes the engine is butter smooth. As far as I'm concerned, it's 
just wasted HP being sucked up by more rotating mass.

-- Craig


>From: Ron Pieper <rapieper@yahoo.com>
>To: Allyn <amalventano1@comcast.net>, audley wilson 
><amwilson@andrew.cmu.edu>,  scirocco list <scirocco-l@scirocco.org>
>Subject: Re: tech: engine balancing - why dont our engines have balancer 
>shafts?
>Date: Mon, 15 Apr 2002 16:45:25 -0700 (PDT)
>
>IIRC, that technology belonged to Mistubishi, and I assume that they
>licensed it, and for some reason VW didn't/couldn't do it.  That's
>right off the top of my head...facts are welcome here...
>
>Ron
>
> > <amalventano1@comcast.net>
> > > wrote:
> > >
> > > >     As the topic states, why dont our engines use balancer
> > shafts? To
> > > > perfectally balance a 4 cylinder engine, you must eliminate the
> > 2nd order
> > > > force generated by the pistons unequal opposition (piston near
> > bottom
> > > > moves less than piston near top - for a given crankshaft
> > rotation).
> > > > The big reason i am asking this is because our engines dont seem
> > all too
> > > > vibration prone as compared to an engine that employs a balancing
> > shaft
> > > > (i.e. the 2.0 DSM engines).     Now before some of you try to
> > think up a
> > > > way to add balancing shafts to our engines, realize that to
> > eliminate the
> > > > 2nd order force, a balancing shaft must rotate at twice the speed
> > of the
> > > > crank.
> > > >     Another wrench to throw in the works is that the balancer on
> > my talon
> > > > was 1:1 driven from the crank, but had internal gearing such that
> > the
> > > > balancer spun at half the speed (i.e. just like the cams).
> > > >
> > > > Allyn Malventano, ETC(SS), USN
> > > > 87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
> > > > 86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7)
> > > > 87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles,
> > original
> > > > clutch, driveshafts, wheels :)
> > > >
> > > >
> > > >
> > > > _______________________________________________
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> > >
> > >
> > >
> > >
> >
> >
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>
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