1.1 These test methods cover the performance of engine oils intended for use in certain diesel engines. They are performed in a standardized high-speed, single-cylinder diesel engine by either the 1K (0.4 % mass fuel sulfur) or 1N (0.04 % mass fuel sulfur) procedure.3 The only difference in the two test methods is the fuel used. Piston and ring groove deposit-forming tendency and oil consumption are measured. Also, the piston, the rings, and the liner are examined for distress and the rings for mobility. These test methods are required to evaluate oils intended to satisfy API service categories CF-4 and CH-4 for 1K, and CG-4 for 1N of Specification D4485. 1.2 These test methods, although based on the original Caterpillar 1K/1N procedures,3 also embody TMC information letters issued before these test methods were first published. These test methods are subject to frequent change. Until the next revision of these test methods, TMC will update changes in these test methods by the issuance of information letters which shall be obtained from TMC (see Annex A15). 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3.1 Exception—Where there is no direct SI equivalent such as screw threads, national pipe threads/diameters, tubing size, or single source equipment specified. Also Brake Specific Fuel Consumption is measured in kilograms per kilowatthour. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements appear throughout the text. Being engine tests, these test methods do have definite hazards that shall be met by safe practices (see Annex A16 on Safety Precautions). 1.5 The following is the Table of Contents: