Steve, Tym, et Listers,
Oh boy, let's get technical!! It looks like we've got two issues going
here, balancing and vibration damping, that are getting a bit mixed up.
The Ford Windsor and many other motors are externally balanced. This is
probably done because of space limitations inside the motor, although I
believe it is possible to internally balance most engines if you think it
is important. (Some people apparently do.) The usual procedure for
balancing your Windsor motor is to use the flywheel and harmonic balancer
(a.k.a., vibration damper) as the external balancing components. But, just
as the primary function of the flywheel is not to balance the engine,
neither is it the primary function of the harmonic balancer. In fact,
internally balanced engines also have external harmonic balancers
(vibration dampers) on the front of the crankshaft. The reason they are put
there is to reduce the torsional strain on the crankshaft that results from
the the torque stresses transmitted to the connecting rod journals, which
are opposed by the torque of the drive shaft. In other words, the
crankshaft is like a spring that twists as you accelerate or decelerate.
Now, if you applied the torsional force steadily, or only change it slowly,
there would be no need for a harmonic balancer. But this is not how we use
our engines, so vibration dampers are used reduce or dampen the torsional
oscillations of the crankshaft caused by rapid changes in applied torque.
This reduces the chances of breaking a crank when quickly increasing or
decreasing throttle, shifting gears, etc. There are also "harmonic" effects
produced by the firing of the cylinders which can set up resonances with
the crankshaft at certain rpms. I think it is fairly obvious that a heavier
harmonic balancer can do this job better, which is why the HiPo damper is
bigger than the standard one. There are also some pretty fancy aftermarket
dampers that I guess work pretty well too.
As far as what is best for your engine, it sure wouldn't hurt to use the
heavier HiPo damper even if you don't plan on running it hard. But,
regardless of how hard you plan to run it, I would strongly urge anyone
rebuilding an engine to have it professionally balanced. I think the last
time I had it done (ca. four years ago) it ran me about $150, maybe a
little less. Oh yes, that silly little counterweight that's supposed to go
on the camshaft has been sitting in a box of parts in my garage the past
twenty-five years. I've long since quit worrying about.
Tym, I would suggest you either get a HiPo damper or perhaps try one of the
aftermarket devices such as the Fluidamper (Vibratech, Inc. Fluidamper 537
East Delavan Avenue Buffalo, New York 14211 716-895-5404). Of course, if
you don't have $150 to spend on balancing your motor, then take Steve's
advise. ;-)
So, there's my two cents worth on the subject, so TTFN,
Bob
At 03:22 PM 7/24/99 -0700, Steve Laifman wrote:
>MWood24020@aol.com wrote:
>
> > In a message dated 7/24/99 4:46:08 AM Pacific Daylight Time,
> tym@mediaone.net
> > writes:
> >
> > << I need a harmonic balancer from a 289.
> > Does anyone have one they're willing to part with? >>
> >
> > Tym-
> > Last I checked (about 3-4 years ago!), the 289 hi-po dampeners were still
> > available.
> > Mike
>
>Mike,
>
>Unsure that he wanted the Hi Po version, from his e-mail. There are
>differences,
>even in a stock balancer, amongst the weight balance. I believe that 3 bolt
>versions were 28 oz and 4 bolt versions were 50 oz, with the flywheel and
>crank
>balance to match.
>
>
>The Hi-Po version is not necessarily a good thing, even though it looks
>"Boss".
>There were additional weights inside the timing chain cover, and a thinner
>timing
>chain to allow it. Many have had these internal weights removed and the
>entire
>engine re-balanced to be correct., Is it worth it?
>
>Steve
>
>
>--
>Steve Laifman < Find out what is most >
>B9472289 < important in your life >
> < and don't let it get away!>
>
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>
Robert L. Palmer
UCSD, Dept. of AMES
619-822-1037 (o)
760-599-9927 (h)
rpalmer@ucsd.edu
rpalmer@cts.com
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