Recent changes in design and performance requirements associated with the trend to higher power outputs have accentuated wear problems in modern engines and have stressed the need for development of suitable lubricants to prolong the useful life of these engines.
The need for better motor oils has necessitated the development of better wear tests for predicting lubricant performance. Wear is determined directly by physical measurements of worn parts, and indirectly by measurement of material worn off a radioactive engine component. Both of these general methods are necessary for a comprehensive evaluation of modern engine lubricants.
This paper describes several laboratory test techniques used in determining wear in both single-cylinder and multi-cylinder engines and their applicability to specific wear problems affecting lubricant development. Piston ring, piston pin, and valve train wear under various operational conditions are discussed.