SEVEN HUNDRED tons of iron, estimated by the authors to be worn annually from the cylinder bores of American automotive engines, cause an annual engine repair bill believed to exceed $1,000,000,000. A large part of this wear is due to corrosion, particularly in severe service such as gasoline-powered delivery vehicles or stationary diesel installations.
Test results indicate that wear rates can be materially reduced by the use of crankcase lubricating oils containing high concentrations of alkalinity. The authors also present examples of radiochemistry research. Radiotracers are used to prove that oil consumed by the engine carries with it the iron debris which it contained at the moment of consumption.
Investigations conducted in the laboratory disclosed that corrosion in the cylinder zone is influenced by three factors of about equal importance: (1) high load can cause critical conditions of corrosion; (2) corrosive wear is rapidly accelerated under low cylinder temperatures; and (3) fuel in which the sulfur content has been raised to 1.0% is a wear promoter. But the tests also disclosed that high wear attributable to any or all of these conditions may be reduced by the use of lubricating oils possessing high concentrations of alkalinity.