Crank bolt to hold damper

Mike69cuda said
There is no vibration path through a helicoil. If the engine is balanced properly there is no vibration to transmit.

Please forgive me for being insistent, but unfortunately, that is wholly missing the actual vibration that is of concern. The vibration IS there. It is not the crank rotating assembly vibration that we think of with an imbalance. It is a high frequency torsional (twisting) vibration within the crank itself.

The whole point of the damper's elastomer (or fluild) is to absorb that vibration and keep the crank from reaching a high frequency resonance that can break it. The damper bolt is cranked to a high torque value to hard-couple the damper hub to the crank, and the vibrational enenrgy flows through the crank snout, the threaded connection, into the damper hub and to the elastomer. The damper ring work as a stable, constant speed rotating mass against which the elastomer or fluid is anchored so it can do its work of 'damping' these vibrations..... which is why it is called a damper!

Please read here:
Harmonic Dampeners: Why They Fail, What to Look For
https://www.klmperformance.com/coll...-balancers-crankshaft-damper-vibration-damper

There is lots of other info on this matter on the www.