Gordon Arnaut wrote:
For example, most V-8 engines come with a harmonic balancer, even though
they have four power pulses for each crankshaft rotation. That's because
there is enough flex in the crankshaft that the crank can begin to resonate
at some rpm within the operational range.

Actually, V-8s have a harmonic balancer because they would otherwise
have a first order imbalance. The physics explanation is pretty long
and doesn't make a lot of sense anyway, but it's because the
crankpins are 90 degrees apart (inline fours don't have this
imbalance because the pins are in pairs 180 degrees apart, but they
have second order imbalance instead... that is what a pair of balance
shafts cures) and the mass on the ends of those crankpins (rods and
pistons) flinging around are at different distances along the
crankshaft. Also, the harmonic balancer on a V-8 is two weights, one
on each end of the crankshaft. A lot of people don't realize there
are two weights, not just the one on the front of the engine.

Harmonic dampers are a different animal. They will smooth out power
pulses on any engine configuration. Harmonic balancers have nothing
to do with power pulses and everything to do with complicated
vibration of large pieces of metal moving back and forth in different
directions and different places.

I think the terms balancer and damper are confused with each other
because they look almost the same- a big part attached to the front
of the crankshaft to make the engine smoother.