THE PRESENT PAPER covers the results obtained in a second survey of fuel-line temperatures. Road tests were made on a large number of 1931 cars operated under various specified conditions, and fuel temperatures were measured in each case at several points in the fuel-feed system. On the average, no material improvement over the 1930 models was found. Individual models had been improved considerably, while others had become worse. This unchanged situation may be due, in part, to the fact that the results of the 1930 survey were not available in time so that full advantage could be taken of the conclusions in designing the 1931 models.
Reasonable protection for most of the 1931 cars as regards fuel cannot be obtained in hot weather if they are run on gasolines having a Reid vapor pressure higher than 7 lb. per sq. in. The production of such a product not only makes difficult the meeting of the requirements necessary for easy engine starting during some seasons of the year but, in addition, materially curtails the available supply of suitable gasoline. The problem of eliminating vapor lock would be greatly simplified in the case of forthcoming models if these cars were equipped with well-designed fuel-feed systems; in fact, such a change in design is the only way of eliminating a large percentage of the vapor-lock troubles. The problem is not very difficult from the design standpoint, and some of the 1931 cars have satisfactory fuel systems. Effective installation of the line leading from the gasoline tank to the fuel-pump, and changes in the position and in the method of lubrication of the fuel-pump, appear to be the two major points involved in solution of the problem.