| The resonance dampened by the balanced crank pulley is a 4th order harmonic. The amplitude will be the largest at bearing #1 (front of the engine), and smallest at the rear of the engine. The amplitude of the torsional strains, and thus vibrations, will increase as the distance from the flywheel increases. Think of how much torsional displacement a crankshaft can see while under load. Top fuel engines have actually used an offset cam grind to account for crankshaft torsional strain while under load. The cam offset increases exponentially from the rear of the engine to the front. Depending on the natural frequency and the length of the crankshaft, this amplitude may or may not be enough to damage the crank bearings. Some cars, such as the Porsche 968, have a 4th order harmonic resonance that occurs higher then the redline, so a harmonic balancer on the crankshaft is not needed since the critical rpm is not reached. Our cars have a relatively short and strong crankshaft, this helps to keep the elastic deformations of the crankshaft itself to a minimum. This in turn causes the crankshaft to have a higher natural frequency and smaller vibrational amplitudes then a similarly sized inline 6 for example. It is possible that the 4th order harmonic happens either at or very near to the factory redline. So a car that doesn’t spend any amount of time near the critical RPM won’t see the negative affects from the non-balanced pulley. Most cars that rev that high consistently enough for the 4th order harmonic to be a significant factor will most likely need a rebuild from wear/failure caused by other factors first anyway. So I guess to answer your question, the wear pattern of your bearings in my opinion is not consistent with what would be expected due to the non-balanced pulley. I would expect bearing #1 to have the most wear, and bearing #6 to have the least. But in the end, opinions are like a.... :)
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