I just looke at my crankshaft today and the same type of holes are present: are from factory balancing until proven otherwise (impossible to prove).
Yup and say you were to balance the crank to a finer tolerance than the factory and drill those holes a little deeper, how could this be proven, what if the factory balanced your crank better than someone elses ?
It's all up to the machinest, had my tyres balanced the other week, didn't seem right above *0 mph, took the car back, 20gms out at the front and 60gms at the back. Same place, same machine different operator !!!!
Yup and say you were to balance the crank to a finer tolerance than the factory and drill those holes a little deeper, how could this be proven, what if the factory balanced your crank better than someone elses ?