The Effects of Oil Additives in the Ball Rust Test

The Ball Rust Test (BRT), a corrosion bench test developed for evaluating the rust preventing qualities of crankcase motor oils, is being proposed as a replacement for the ASTM Sequence IID engine test. Details of this bench test are described in the paper “Development of the Ball Rust Test - A Bench Test Replacement for the Sequence IID Engine Test.” In this paper, a good correlation was established between rust performance in the BRT versus the IID engine test rust rating for a variety of oils. Following the development of the BRT, a comprehensive study was conducted using this bench test to define the effectiveness of oil additive type and concentration on rust inhibition. This paper summarizes these results and offers insight into effective rust control in a corrosive environment.

High-base metallic sulfonates were found to be most effective at preventing rust primarily due to preservation of alkalinity. Effects of other additives, such as low-base detergents and dispersants, on rust prevention in the BRT are also reported. These findings are similar to previously published additive effects on rusting in short-trip service tests.