Aasco flywheel is here.

[thstone]

I am having a LWFW (and new clutch) installed right now. Should be done by tomorrow.

After reading through this thread (and others), there is no way that removing the DMFW and installing a LWFW can cause crankshaft failure. No how, no way. All production engines are factory balanced to the degree necessary (along with the proper design considerations such as bearing placement and type) to ensure proper and sufficient engine balance.

No engine is in perfect balance, no matter how much time and effort you put into it. Some engines can be in better balance than others but meeting the engine balance criteria to ensure long-term engine reliability is easily met by standard design and production methods.

Harmonics are a red herring in this discusion. Harmonics have very little energy unless a forcing function is driving at one of the harmonic frequencies. Yes, this can happen to a really old bridge in high winds but can't happen in a modern engine because the only forcing function in an engine is the cylinders firing which create the primary or fudamental frequency.

Beyond that, there's nothing in an engine (analogous to the wind in the bridge example) that would drive a harmonic with sufficient energy to cause catastrophic failure of the engine.

The DMFW is meant to reduce minor engine vibration from being transmitted to the body and interior (as part of NVH control), not to keep the engine from self destructing.