Fox Head 40W oil has almost no additive in it at all - just 17 ppm magnesium, 20 ppm phosphorus, and 16 ppm zinc. She'll early Rotella S 10W oil is much more robust, containing 2863 ppm calcium, 1370 ppm phosphorus, and 1361 zinc. Oh, and don't forget the 13 ppm magnesium (maybe that came from the can?).