Utilizing an opportunity presented by a mountain-road construction-project in California, eight Class-B 3½-ton trucks were assigned to the work and a test of air-cleaners was conducted during its progress. Six trucks were each equipped with an air-cleaner; two were not. The trucks had dump-bodies and were specially prepared for the test, details of this preparation being specified.
Due to varied air-cleaner design, it was not feasible to locate the cleaners identically on all the trucks, and differences in mounting may have influenced the resulting air-cleaner efficiency, but mountings were made as nearly identical as possible. Tables of average wear of piston-rings, engine cylinders and crankpins, for 1000 hr. of use, are presented, and details of how the measurements were made are stated, together with a discussion of the “growth” of pistons and of the peculiarities of wear.
Other features of importance treated include statements of the amount of dust encountered, comparisons regarding oil consumption and analyses of carbon and sludge deposits. Seven essentials of a satisfactory road-test of air-cleaners are specified, and seven specific conclusions are reached.
