As the dreaded torsional damper is usually used to damp the dreaded Harmonic Vibrations , there could be some merit in a isolastic Flywheel . Though itd be rotationally iso howsited .
this is alledgedly part of it .
Straight Eight cranks suffered HARMONIC problems, which is where a torsional damper comes in .The hamonic bit means forces overlap multiplying or cumulative loadings .
Which is where if some silly ass puts the counterweight flanks in some silly position, its started the prgressive rotational enterprise which the fireing impulses add to .
Increaseing the power output .

And the rate of rotation is more constant .
Some type chucked a B.M.E.P. ( pressure guage ) on a cylinder and recorded the figures at ea degree of rotation .It varys considerably, even immensly ( on a single Cyl ) from
the Max. + to slightly Neg. pressure ( in the combustion chamber ).thus the acceleration of the crank through each rotation is not constant .
The'Harmonic ' problem is if as the force from one peak input travles along the shaft , it coincides with the next ( at its source perhaps ) Doubling the transmitted strain / impulse
at that point in the material .
thus flywheel mass is part of a equation in loadings ( rotationally ) in the parrallel crank pin two ( main ) bearing crank assembly . As In if there is a impusle at the Rt. crankpin , transfered in part to a
non perpendicular rotational ( sideways force at flywheel / crank centre ) coincideing through loadpath ( crank material ) with the next impuse from the left crankpin , the ragged helical pattern of
strain is not passed advantageously as regards the materil ( crankwaeb ) .
Fudge .