well so much for the "Kontrolierte Qualitat" on those fasteners.

You did tourque it properly right?

Indeed some of the benefits of thread rolling (compressive pre-stress for example) are lost if it is done before heat treating but some remains such as improved grain orientation and the lack of cut grains. Fatigue strength of the rolled threads is much better if the rolling is done after heat treating but this wears out the rolling dies sooner so it is done only on the highest performance fasteners. It is not routine practice with typical 12.9 class strength fasteners. Cheers, Jim

Wrong bolt lenght. The bolts that use the 9 hole crankshaft use less torque that the 6 bolts crankshafts. The bolts that correspond to the 9 hole crankshaft is short compare to the flywheel bolt used on the 6 hole crankshaft.