Engine Rust - Measurements by a New Technique Shed Light on Why Lubricated Parts Rust 630157
An electric corrosometer was applied to improve speed and precision of automotive engine rust measurements. Studies of the relationship of rusting rates to engine operating conditions and fuel variables led to the identification of important rust-promoting factors in an engine.
Sulfur and halogens in the fuel and moisture condensation on cylinder walls were found to cause major corrosive effects.
A mechanism involving condensation of acidic moisture on the cylinder wall during the high pressure (power) stroke and transport of this moisture in the oil film past the piston rings and through the oil circulating system to the site of rusting accounts for the large effects of induction air humidity as well as effects of other variables on engine rusting tendencies.