One of the problems, fortunately upgradeable, in the M96 engine is the design of the crankshaft which has an approximate 50mm distance between bearing 7 and the crankshaft seal surface. Additionally the chain that drives the crankshaft is located at the back of the engine (looking toward front of the car). The pressures from these combined forces cause excessive vibrations on the crankshaft.
The picture to the right compares the end of an aircooled crankshaft to the end of a water-cooled (M96) crankshaft. While both crankshafts have a flywheel connected to the end, the M96 motor has has the added forces of chain, a heavy flywheel-clutch combination (42lbs.), and a longer distance from its support bearing. All forces working against a smooth spinning crank.
The picture to the right compares the end of an aircooled crankshaft to the end of a water-cooled (M96) crankshaft. While both crankshafts have a flywheel connected to the end, the M96 motor has has the added forces of chain, a heavy flywheel-clutch combination (42lbs.), and a longer distance from its support bearing. All forces working against a smooth spinning crank.