Lubricant compositions for reducing timing chain stretch

A method for reducing timing chain stretch in an engine comprising a step of lubricating said timing chain with a lubricating oil composition comprising:

• a major amount of a base oil;
• and
• a minor amount of an additive package including:
• a) at least one overbased calcium detergent in an amount sufficient to provide 1000 ppm to 1800 ppm by weight of calcium to the total weight of the lubricating oil composition,
• b) at least one borated dispersant,
• c) a metal dialkyl dithiophosphate, and;
• d) at least one oil soluble molybdenum compound;
• wherein the lubricating oil composition has a TBN value of at least 7.5 mg KOH/gram lubricating oil composition, determined using the method of ASTM-2896, at least 80 ppm of molybdenum based on a total weight of the lubricating oil composition, a weight ratio of total calcium in the lubricating oil composition to total molybdenum in the lubricating oil composition of less than 8.4;
• and a weight ratio of nitrogen from the dispersant in the lubricating composition to total boron in the lubricating oil composition of from 2.6 to 3.0, wherein the lubricating oil composition has a ratio of total ppm of boron in the lubricating oil composition to the TBN of total detergent in the lubricating oil composition of from 50 to 63, and the lubricating oil composition is capable of reducing the timing chain stretch in an engine to 0.09% or less, as measured by the Ford Chain Wear Test over 216 hours.

A method for reducing timing chain stretch in an engine comprising a step of lubricating said timing chain with a lubricating oil composition comprising:

• a major amount of a base oil;
• and
• a minor amount of an additive package including:
• a) at least one overbased calcium detergent in an amount sufficient to provide 1000 ppm to 1800 ppm by weight of calcium to the total weight of the lubricating oil composition,
• b) a borated dispersant that is a reaction product of an olefin copolymer, a succinic anhydride, and at least one polyamine, and wherein the borated dispersant is post-treated with an aromatic carboxylic acid, an aromatic polycarboxylic acid, or an aromatic anhydride wherein all carboxylic acid or anhydride groups are attached directly to an aromatic ring, and with a non-aromatic dicarboxylic acid or anhydride having a number average molecular weight of less than 500,
• c) a metal dialkyl dithiophosphate, and;
• d) at least one oil soluble molybdenum compound;
• wherein the lubricating oil composition has a TBN value of at least 7.5 mg KOH/g of the lubricating oil composition, determined using the method of ASTM-2896, at least 80 ppm of molybdenum based on a total weight of the lubricating oil composition, a weight ratio of total calcium in the lubricating oil composition to total molybdenum in the lubricating oil composition of less than 8.8;
• and a weight ratio of nitrogen from the dispersant in the lubricating composition to total boron in the lubricating oil composition of from 2.6 to 3.0, and the lubricating oil composition is capable of reducing the timing chain stretch in an engine to 0.09% or less, as measured by the Ford Chain Wear Test over 216 hours.