Comp Cams has put out a tech service bulletin concerning the increasing events of cam lobe failure in recent times. Part of their analysis of the failures is that the forced reduction of magnesium and zinc in modern oils has reduced the lubricity of the new oils. (Modern engines use roller cams) They recomend the use of Rotella T for cam breakin claiming that the diesel or HDEO's contain higher concentrations of these elements resulting in increased scuff protection for the cam lobes. I would appreciate any comments on this subject.