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The paper describes increased bearing capacity from 1918 to 1956 based on New Departure Laboratory endurance test results and shows an increased capacity trend up to about 1946 at which time the optimum steel cleanliness of 52100-51100 steel was obtained by an air melting practice. The paper describes further advance in bearing capacity by the use of vacuum melting practices and also indicates that optimum cleanliness has not been consistent due to inability to control the process to the degree required for ball bearing steels.

Compression ratios ranging from 4:1 to 16:1 have been investigated in a special single-cylinder engine, as have quench or squish areas from 0 to 50 per cent piston coverage at each compression ratio. The following conclusions can be drawn from this work: 1. As compression ratios are increased, gains are subject to the law of diminishing returns. This is true of brake horsepower, as well as indicated power and thermal efficiency. At higher compression ratios, the only thing still increasing rapidly is the fuel antiknock requirement. 2. Quench area, in the range investigated, had no effect on power or thermal efficiency. 3. Quench area does have large and important effects on fuel antiknock requirements and engine severity. Fuel sensitivity, under certain conditions, can be a real asset instead of a liability. 4.

The John Deere Waterloo Tractor Works, as manufacturers of farm tractors, does not manufacture oil seals. We rely on the manufacturers of oil seals for design assistance. After establishing the initial design, laboratory and field tests are required for verification. One of the seal applications is on the crankshaft which must keep crankcase and transmission lubricants separated. Reliability and long life are imperative. Alertness as to the effect of detail changes on seal life is necessary to maintain long service life. The front wheel bearing seals may be subjected to submersion in water and mud. Packing, lip and face type seals have been tested with the face type proving the most rugged, although the most costly of the three types. A problem of design and space which was encountered in a hydraulic pump was overcome by design changes in the seal and in the pump. Constant vigilance on assembly methods and tool maintenance is a requirement to keep quality level high.

The results of a survey of spark plug fouling in 193 late-model passenger cars of four popular makes showed that approximately one-third of the spark plug sets were fouled sufficiently to cause at least a 20 percent decrease in vehicle performance. While the vehicle models and number of cars involved are limited and do not completely represent the car population nor types of service, the survey did provide a sample of the three main price classes of cars. The results indicate that a considerable amount of spark plug fouling exists in vehicles driven in city and city-suburban service. Recognition of spark plug fouling by car owners varied with car make. Dynamometer and road-test procedures have been devised for studying various factors affecting spark plug fouling. Careful control of test variables has produced acceptable correlation between these procedures.