Flat tappet cam life

[rdorman]

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."

[rdorman]

I also asked Ed specifically about the 5W-40 rotella T synthetic that I currently use. Here is his reponse:

"Shell Rotella T Synthetic Oil has not yet been reformulated for API CJ-4, though we expect to release the reformulation in the next couple of months. At the current time, Shell Rotella T Synthetic Oil SAE 5W-40, in the API CI-4 Plus/SL formulation, contains approximately 1600 ppm, or 0.16%, zinc."