Search Results

The development of an improved Reciprocating Viscometer for use in predicting low temperature cranking characteristics of engine oils is described. Correlations between full-scale engine viscosities and viscosities determined using the Reciprocating Viscometer are included along with repeatability and reproducibility data obtained at 0 F and -20 F in an ASTM round-robin evaluation. Results show that this viscometer can predict the low temperature cranking characteristics of engine oils.

STUDY of the foaming of engine oil by the CLR Group on Foaming has led to the development of what is called antifoam agents, which, when added to the oil, eliminate foaming under most conditions. These inhibitors of foam, the authors report, have no detrimental effect on the oil. Nonfoaming engine oils are now available for the Army and Navy; and, as far as can be determined, complaints from foaming of Army and Navy specification engine oils have now been eliminated.

This paper discusses the major difficulties experienced in the operation of two-cycle engines. For the most part two-cycle engines operate under full load for sustained periods, thus developing high engine temperatures which promote deposit formation in engines. Problems analyzed are spark plug failure, preignition, engine wear, and rust and corrosion. The paper describes test procedures used to investigate these problems, as well as illustrating how the difficulties could be minimized by use of properly formulated additive-containing oils.

ONE of the simplest and cheapest methods yet devised to augment cutting tool life, and at the same time increase cutting speeds, is described in these two papers by the authors, who pioneered in developing the novel hi-jet system, which substitutes a fine, forced jet of oil for the customery flood type of lubrication during cutting operations. In Part I, Mr. Pigott reviews the improvements resulting from applying cutting liquids in the hi-jet manner. He compares the results with those obtained under the former system. He also describes the adaptations of various recording instruments and other improvements developed during the running of hi-jet tests. In Part II, Mr. Colwell describes many practical applications of hi-jet. Mr. Colwell considers the method to mark a revolutionary advance in the art of removing metal. He points out that the combination of cooling plus oil vapor lubrication supplies the factor which has produced superior results.

Combined efforts by oil companies and engine manufacturers have improved the overall efficiency and performance of two-cycle gasoline engines. One striking trend has been toward the use of leaner oil-fuel mixtures to accomplish lubrication. The use of less oil reduces smoking and air pollution (important in two-cycle automotive engine operation), reduces engine port deposits, preignition, and cost of operation. Experience has shown that the composition of the oil becomes increasingly important as its concentration in the fuel is reduced. Lean mixtures of some conventional oils are not satisfactory, and with all oils some lower concentration is reached where serious problems are encountered, such as lack of lubrication, increased engine wear, and decreased engine cleanliness.

RESULTS of a laboratory study of some of the factors causing wear, scuffing, and spalling in passenger-car engines, with emphasis on the lubricating oil variables involved, are reported in this paper, which is part of the Symposium on Cam and Tappet Wear. The tests show that piston-ring and valve-lifter wear and spalling of some valve-lifter materials seem to be greater with low-viscosity oils such as SAE 5W-20 and 10W. Certain antiwear lubricating oil additives reduce valve-lifter and ring wear but may increase spalling of chilled iron lifters. However, using an oil with good antiwear properties for engine break-in will not prevent future lifter wear if the engine is operated with an oil of poor antiwear characteristics.