An overbased metal detergent grease comprising at least one of polyalkylene glycol and/or an acid having at least one of both a nitrogen and a sulfur atom. The grease has improved extreme pressure performance as measured by the Standard Test Method for Measurement of Extreme-Pressure Properties of Lubricating Grease (Four-Ball Method), ASTM D2596.

Methods of making an overbased metal detergent grease comprising using at least one of polyalkylene glycol and/or an acid having at least one of both a nitrogen and a sulfur atom. Methods of lubricating mechanical components using the grease comprising contacting the mechanical component with the grease. Mechanical components can include gears, drivetrain elements, bearings, hinges, or combinations thereof.

A method for improving wear control of a steel surface lubricated with a lubricating oil through the generation of thick tribofilms. The method includes: (i) using as the lubricating oil a formulated oil, the formulated oil having a composition comprising at least one lubricating oil base stock as a major component; and at least one lubricating oil additive, as a minor component; and (ii) forming a tribofilm on the steel surface. In time-step tribofilm formation measurements of the lubricating oil by a mini-traction machine (MTM) at constant slide-to-roll ratio (SRR), the saturation traction coefficient (f.sub.s), which correlates to tribofilm thickness on the steel surface, is greater than about 0.11. In the method of this disclosure, elongation of timing chain due to wear of chain link pins is less than about 0.07%, as determined by Ford Chain Wear (FCW) test conducted in accordance with ILSAC GF-6 specification. The lubricating oils are useful in internal combustion engines.

A method for improving wear control of a steel surface lubricated with a lubricating oil through the generation of thick tribofilms. The method includes: (i) using as the lubricating oil a formulated oil, the formulated oil having a composition comprising at least one lubricating oil base stock as a major component; and at least one lubricating oil additive, as a minor component; and (ii) forming a tribofilm on the steel surface. In time-step tribofilm formation measurements of the lubricating oil by a mini-traction machine (MTM) at constant slide-to-roll ratio (SRR), the saturation traction coefficient (f.sub.s), which correlates to tribofilm thickness on the steel surface, is greater than about 0.11. In the method of this disclosure, elongation of timing chain due to wear of chain link pins is less than about 0.07%, as determined by Ford Chain Wear (FCW) test conducted in accordance with ILSAC GF-6 specification. The lubricating oils are useful in internal combustion engines.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an overbased sodium detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, including sulfonate detergents with a metal ratio of at least 5.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an overbased sodium detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, including sulfonate detergents with a metal ratio of at least 5.

A metal-containing detergent, suitable for use as a lubricant additive, in the form of a concentrate in oil in which a basic metal-containing material is maintained in dispersion or solution in the oil by a gemini surfactant system comprising, or being derivable or derived from, a double bond-unsaturated carboxylic acid having 8 to 30 carbon atoms, the double bond or bonds of which being functionalized to carry polar groups across or on the double bond or bonds and the carboxylic acid group or groups thereof being functionalized to become an amide or ester group carrying at least one alkyl group having 4 to 20 carbon atoms.

A metal-containing detergent, suitable for use as a lubricant additive, in the form of a concentrate in oil in which a basic metal-containing material is maintained in dispersion or solution in the oil by a gemini surfactant system comprising, or being derivable or derived from, a double bond-unsaturated carboxylic acid having 8 to 30 carbon atoms, the double bond or bonds of which being functionalized to carry polar groups across or on the double bond or bonds and the carboxylic acid group or groups thereof being functionalized to become an amide or ester group carrying at least one alkyl group having 4 to 20 carbon atoms.

A metal-containing detergent, suitable for use as a lubricant additive, in the form of a concentrate in oil in which a basic metal-containing material is maintained in dispersion or solution in the oil by a gemini surfactant system comprising, or being derivable or derived from, a double bond-unsaturated carboxylic acid having 8 to 30 carbon atoms, the double bond or bonds of which being functionalized to carry polar groups across or on the double bond or bonds and the carboxylic acid group or groups thereof being functionalized to become an amide or ester group carrying at least one alkyl group having 4 to 20 carbon atoms.

A metal-containing detergent, suitable for use as a lubricant additive, in the form of a concentrate in oil in which a basic metal-containing material is maintained in dispersion or solution in the oil by a gemini surfactant system comprising, or being derivable or derived from, a double bond-unsaturated carboxylic acid having 8 to 30 carbon atoms, the double bond or bonds of which being functionalized to carry polar groups across or on the double bond or bonds and the carboxylic acid group or groups thereof being functionalized to become an amide or ester group carrying at least one alkyl group having 4 to 20 carbon atoms.

Disclosed is a lubricating oil composition which comprises: (a) a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100 C. in a range of about 2 to about 50 mm.sup.2/s, (b) an overbased metal salt of an alkyl-substituted phenate detergent, wherein the alkyl group is derived from an isomerized normal alpha olefin having from about 10 to about 40 carbon atoms per molecule and having an isomerization level (I) of the normal alpha olefin of from about 0.1 to about 0.4 in an amount to provide at least 1000 ppm of calcium, (c) one or more magnesium-containing detergents having about 100 to about 1000 ppm of magnesium, based on the total weight of the lubricating oil composition, and (d) one or more zinc dialkyl dithiophosphate compounds derived from a primary alcohol.