Re: [FWDLK] Harmonic Balancers

[David Homstad <Dhomstad@xxxxxxxxxxx>]

Not all engines have dampers. The engines I am most familiar with are the 56
Dodge V8s. Only the 315 Poly 4 bbl and the D500 engine had a damper. The
270/315 Poly 2 bbl engines (the most common) did not have a damper; they
only had a pulley attached to the hub at the front of the crankshaft. In
later years, dampers were more common and probably on all engines.

The rubber between the inner and outer parts of the damper is designed to
have a consistency or hardness that dampens crankshaft vibrations at the
frequencies that the engine operates at. Any vibration is bad. At certain
frequencies, the energy causing of a vibration can be added to existing
vibrations to make the amplitude grow. This is called a resonance frequency.
This is like pushing someone on a swing. If you time each push to add energy
to the swing, the height of the swing grows. If the amplitude grows too
large, it can be damaging. The rubber damper absorbs energy like applying
friction to the swing. After many years and lots of heat, the rubber may
harden, making it ineffective at dampening or likely to fracture.

Dave Homstad
56 Dodge D500

-----Original Message-----
From: Forward Look Mopar Discussion List
[mailto:L-FORWARDLOOK@xxxxxxxxxxxxx]On Behalf Of Dave Stragand
Sent: Tuesday, January 22, 2002 9:40 AM
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Subject: Re: [FWDLK] Harmonic Balancers (was: Savannah's Day Out, Part II)

All internal combustion engines (with the possible exception of Wankel
rotaries, I'm not sure) have some type of damper/balancer
(interchangable terms).

If yours was bad, the engine would shimmy/shake quite a bit.  Picture
your engine.  Lots of things moving up & down, thus back and forth.
That's linear motion.  A balancer helps keep rotational motion/inertia
in the engine.  That's the "balancing" part.

In addition, every time an engine fires (and every time it goes under
compression), it puts a bit of torsional twists on the crankshaft.  The
balancer helps keep that twist in check, much like a shock absorber.
That's the "dampening" part.  It smoothes out the engine's balance
immensely.  If you've ever seen an engine run without a balancer, it
looks like some kind of demon-possessed machine that's trying to jump
free of the vehicle, truly scary.

Most balancers consist of an inner and outer ring, with a rubber ring
holding them together (although some, such as those made by FluidDampr,
use a thick liquid as a binder).  The rubber absorbs the shock, while
the heavy inner and outer steel rings provide the needed inertia
necessary for both balacing and dampening.

On most engines, the balancer is located at the front of the engine, on
the end of the crankshaft.  The main pulley is usually bolted directly
onto it.  It also usually has the timing mark on it, as it does on all
of our engines from 55-61.

-Dave

-----Original Message-----
From: Ron Waters [mailto:ronbo97@xxxxxxxxx]
Sent: Tuesday, January 22, 2002 9:47 AM
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Subject: Re: [FWDLK] Savannah's Day Out, Part II


Here's a question from one of us engine-technology-challenged folks : Do
all
our late 50s Mopars have harmonic dampers or only some of them ?  Is
this
the same thing as a harmonic balancer ?  How would I know if mine was
bad ?
Where in the engine is this creature located ? And one more...do the
301/318/326 late 50s small V8s have one ?

Thanks in advance,

Ron