Join Date: Sep 2008
Location: Honolulu, HI, USA
Some of BMW's Big Six engines from the 60's through 80's - the M30 - had issues with oil feed to the front-most cam lobe but it didn't show up in 65000 miles as yours apparently has. The weak spot was the front bolt through the oil spray bar would loosen and the bar would lose all pressure, resulting in uneven oil delivery, and a work cam lobe or several if not checked.
Surprising that yours went bad at 65,000, had you had your valves adjusted? That service procedure should have caught the problem.