THE paper, “Review of Temperatures, Road-Test Engines,”1 presented at the Semi-Annual Meeting of the Society, June 5, 1941, by B. E. Sibley, gave operating temperature data on a fleet of 16 road-test units operated in southern Arizona during August, 1940.
This paper deals with the changes occurring in the five oils used in that test work and with the nature and amount of deposits left in the various engines by the oils.
Results of oxygen-absorption tests and modified Underwood tests of the five oils are given and show the general behavior characteristics that might be expected of the oils in service. Dynamometer stand tests of the same oils in two each of three makes of large production passenger-car engines are described and the oils are rated in order of descending merit, as measured by progressive oil change and final engine condition.
Changes occurring in both oil and engine condition during extensive road tests of these oils are then shown and compared with chemical laboratory and engine-stand test results.