Function of the "intermediate shaft"?

[hooper4s]

Just wondering what the heck this thang does?

[nick49]

The intermediate is a jack shaft of sorts that runs from the front of the motor to the rear, below and parallel to the crankshaft. It is driven by the crankshaft and drives the overhead camshafts. The Porsche motors are unique, I think, in that one bank is driven from the front of the intermediate shaft and the other from the rear. As I understand it, the early M96 motors suffered from intermediate shaft bearings that were undersized, and many motors had shafts breaking or other related failures. Later, as a factory fix, much larger bearings were used to support this shaft. The replacement motor that was fitted to my '99 996 has the larger bearings as by the tech that did the install.