AndreasPassat· PassatWorld Elder
It basically boils down to the cam sprocket not being loose on the bank 1 camshaft. With the cam sprocket being loose (by loose I mean just enough to turn on the tapered portion of the camshaft). When the camshafts have their static timing set to the timing marks on the cam caps and the static timing on the belt set by the marks on the crankshaft pulley relative to the marks on the plastic cover, then the diamond shaped keys will be exactly horizontal. Basically it allows you a finite adjustment that retarding or advancing the belt by one tooth can't achieve.