Actually, it is pretty simple; a short chain on the front of the engine drives the intermediate shaft. At the rear of the engine, the intermediate shaft turns long chains that drive the cams. The rear of the IMS is supported by a sealed bearing that is bolted to a flange behind the flywheel; this is the “problem child” as the seals prevent lubrication by the engine oil, but when the seals begin to fail, allow the ultra thin 0-40W engine oil to wash the grease out of the bearing, but not let enough in to cool and properly lubricate the bearing. Over time, the bearing balls start to gall and eventually the assembly fails, allowing the long rear cam chains to go slack while the engine is turning and jump time. As the M96 is and “interference” engine, pistons start hitting valves, and total mayhem takes over………
