From ED, a chemist at Shell:
"Shell Rotella T Multigrade Oils in the API CJ-4 formulations contain approximately 1200 ppm
zinc. This is down slightly from the typical 1400 ppm
zinc found in the previous API CI-4 Plus formulation. However, in critical applications, such as gasoline engines with flat tappets, push rods, etc., we believe the new formulations still have enough
zinc to provide adequate protection. In diesel engines, the new formulations gave the best protection from wear ever seen in the Shell Rotella T Multigrade product line."