Cylinder Bore Wear

Abstract

The author has been responsible for the design of engines for a motor car in which the life of the cylinder bore over a period of ten years and a total of eight million engines is 12,000 miles per 0·001 inch wear. The factors contributing to this result are as follows: (1) thermostatically controlled cooling for water at a minimum temperature of 145 deg. F., preferably 160 deg. F.; (2) crankcase ventilation to eliminate the effects of blow-by in the oil sump; (3) adequate oil supply to cylinder bores; (4) complete control of the lubricant at the piston rings, not at the source of supply of the oil; (5) control of gas blow-by at the rings; (6) leanest possible mixture ratios for general operating conditions; (7) close attention to the type of fuel used to ensure that it is properly vaporized; (8) a uniform hot metal temperature; and (9) an accurate spark advance mechanism. All these factors are discussed by the author in detail, special attention being paid to the testing of piston rings in the laboratory, the correct use of thermostats, and crankcase scavenging.