Abstract: Disclosed herein is a trunk piston engine lubricating oil composition comprising (a) a major amount of an oil of lubricating viscosity; (b) one or more carboxylate-containing detergents comprising a salt of an alkyl-substituted hydroxyaromatic carboxylic acid, wherein at least about 50% of the alkyl moiety of the alkyl-substituted hydroxyaromatic carboxylic acid comprises C26+ alkyl groups derived from one or more normal alpha olefins; and (c) one or more zinc dithiophosphates in an amount of about 0.02 to about 0.12 wt. % in terms of phosphorus content.

Abstract: Disclosed herein is a neutral or overbased salt of a sulfurized alkylhydroxyaromatic compound obtained by the process comprising the steps of (a) sulfurizing an alkylhydroxyaromatic compound derived from alkylation of a hydroxyaromatic compound with one or more olefins comprising C9 to C18 oligomers of monomers selected from propylene, butylene or mixtures thereof to provide a sulfurized alkylhydroxyaromatic reaction product; (b) removing any unsulfurized alkylhydroxyaromatic compound from the sulfurized alkylhydroxyaromatic reaction product of step (a) to obtain a sulfurized alkylhydroxyaromatic compound substantially free of the unsulfurized alkylhydroxyaromatic compound; and (c) neutralizing the sulfurized alkylhydroxyaromatic compound of step (b) to provide a salt of the sulfurized alkylhydroxyaromatic compound, wherein the overbased salt of the sulfurized alkylhydroxyaromatic compound contains less than about 2% by combined mass of the unsulfurized alkylhydroxyaromatic compound and its unsulfurized metal