US Patent 7906469 Lubricating oil compositions

Lubricating oil compositions having a sulfated ash content of no more than 1.0 mass %, which contain a major amount of oil of lubricating viscosity, a minor amount of calcium salicylate detergent, an amount of a magnesium-based detergent providing the lubricating oil composition with at least 200 ppm of magnesium, an amount of a sulfur-containing molybdenum compound providing the lubricating oil composition with at least 20 ppm of molybdenum, and at least one nitrogen-containing dispersant providing the lubricating oil composition with at least 0.9 mass % nitrogen, which compositions provide improved top ring wear protection in internal combustion engines.