Harmonic balancers are not really about balance but "absorbing" the twisting harmonics of a crankshaft.The longer the crank,the worse it can be. Some 4 cylinder engine have no dampers.Dave mentions the early Chevy V-8's with no actual damper.I guess the theory is the short forged crank and somewhat lightweight parts didn't need one.Or GM cheaped out...........
Denny,on a 235 type damper the only place you can see the rubber is two small holes.Have you drilled out the rivets to separate the pieces to have a look? I did out of boredom and it's a very thin disc of rubber like material.It looked ok but who knows if the material has the same properties engineers designed into it after a million cycles and 60 years.
In simple terms,I am simple,lol,the rubber separates the hub on the crank to the heavy interia piece.The harmonics are turned into heat from the "wiggling" action allowed by the rubber.
The roadway isn't littered with broken 235 cranks so perhaps it's not a big issue for the way these engines are used.
