I worked on many 2 cycle detroit and also 4 cycle and the only thing I have ever put in them is Rotella 15w40. It works real good and has not failed me yet. But in rental equiptment they tend to tear it up and the oil gets changed early for some reason or anouther. But it works good. New and old they all seam to work. Rotella Has a high zinc content as well. Thats my experiance with it. Good luck.
