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    ASTM D6750 - 15a

    Standard Test Methods for Evaluation of Engine Oils in a High-Speed, Single-Cylinder Diesel Engine—1K Procedure (0.4 % Fuel Sulfur) and 1N Procedure (0.04 % Fuel Sulfur)

    Active Standard ASTM D6750 | Developed by Subcommittee: D02.B0.02

    Book of Standards Volume: 05.03

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    Significance and Use

    5.1 These are accelerated engine oil tests (known as the 1K and 1N test procedures), performed in a standardized, calibrated, stationary single-cylinder diesel engine using either mass fraction 0.4 % sulfur fuel (1K test) or mass fraction 0.04 % sulfur fuel (1N test), that give a measure of (1) piston and ring groove deposit forming tendency, (2) piston, ring and liner scuffing and (3) oil consumption.

    5.2 The 1K test was correlated with vehicles equipped with certain multi-cylinder direct injection engines used in heavy duty and high speed service prior to 1989, particularly with respect to aluminum piston deposits, and oil consumption, when fuel sulfur was nominally mass fraction 0.4 %. These data are given in Research Report RR:D02-1273.9

    5.3 The 1N test has been used to predict piston deposit formation in four-stroke cycle, direct injection, diesel engines that have been calibrated to meet 1994 U.S. federal exhaust emission requirements for heavy-duty engines operated on fuel containing less than mass fraction 0.05 % sulfur. See Research Report RR:D02-1321.9

    5.4 These test methods are used in the establishment of diesel engine oil specification requirements as cited in Specification D4485 for appropriate API Performance Category oils (API 1509).

    5.5 These test methods are also used in diesel engine oil development.

    1. Scope

    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:








    Referenced documents




    Summary of Test Methods


    Significance and Use





    General Laboratory Requirements



    Test Engine



    Test Engine Accessories and Parts


    Reagents and Materials


    Test Oil Sample Requirements


    Preparation of Apparatus



    Engine Inspection



    Engine Pre-Test Lubrication System Flush



    Engine Pre-Test Measurements and Inspections



    Engine Assembly



    Pressure Testing of Fuel System Assembly


    Calibration of Engine Test Stand



    General Requirements and Frequency of Calibration






    Specified Test Parameters



    Calibration Test Acceptance Criteria



    Action on Rejection of Calibration Test



    Test Numbering



    Reference Oils



    Severity Adjustments


    Engine Operating Procedure



    Engine Run-In



    Cool-Down Procedure



    Warm-Up Procedure



    Operating Conditions and Oil Additions



    Measurement of Oil Consumption



    Sampling Used Oil



    Shutdowns, Lost Time and Off Tolerance Conditions



    Recording of Exhaust Temperature



    Air-Fuel Ratio Measurement



    Recording of Engine Conditions



    Humidity Requirements/Calibration/Measurement


    Inspections, Photographs and Measurements



    Reference to Reporting Form



    Pre-Test Measurements of Engine Parts



    Post-Test Information



    Oil Inspections





    General Directions



    Electronic Transmission of Test Results (Optional)



    Reporting Calibration Test Results


    Precision and Bias







    Specifications for Test Engine and Engine Build

    Annex A1

    Intake Air System Details

    Annex A2

    Exhaust System Details

    Annex A3

    Cooling System Details

    Annex A4

    Oil System Modifications and Instrument Locations

    Annex A5

    Other Pressure and Temperature Measurement Locations

    Annex A6

    Oil Consumption Linear Regression Method

    Annex A7

    Test Fuel Specifications

    Annex A8

    Lubrication System, Flush Apparatus and Procedure

    Annex A9

    Engine Operating Conditions

    Annex A10

    Procedure for Rating Piston and Liner

    Annex A11

    Calculation of Percent Offset and Percent Deviation

    Annex A12

    1K/1N Test Reporting

    Annex A13

    Parts List by Part Number (P/N) and Warranty

    Annex A14

    Role of Test Monitoring Center

    Annex A15

    Safety Precautions

    Annex A16




    Humidity Data

    Appendix X1

    Statistical Equations for Mean and Standard Deviation

    Appendix X2

    Examples of Forms for Reporting

    Appendix X3

    Optional Recording of Oil Pass Limits

    Appendix X4

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D86 Test Method for Distillation of Petroleum Products at Atmospheric Pressure

    D93 Test Methods for Flash Point by Pensky-Martens Closed Cup Tester

    D97 Test Method for Pour Point of Petroleum Products

    D130 Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test

    D235 Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Dry Cleaning Solvent)

    D287 Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method)

    D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)

    D482 Test Method for Ash from Petroleum Products

    D524 Test Method for Ramsbottom Carbon Residue of Petroleum Products

    D613 Test Method for Cetane Number of Diesel Fuel Oil

    D664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration

    D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method

    D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption

    D1796 Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure)

    D2425 Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry

    D2500 Test Method for Cloud Point of Petroleum Products

    D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry

    D3117 Test Method for Wax Appearance Point of Distillate Fuels

    D3524 Test Method for Diesel Fuel Diluent in Used Diesel Engine Oils by Gas Chromatography

    D4485 Specification for Performance of Active API Service Category Engine Oils

    D4737 Test Method for Calculated Cetane Index by Four Variable Equation

    D4739 Test Method for Base Number Determination by Potentiometric Hydrochloric Acid Titration

    D5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)

    D5186 Test Method for Determination of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation Turbine Fuels By Supercritical Fluid Chromatography

    D5844 Test Method for Evaluation of Automotive Engine Oils for Inhibition of Rusting (Sequence IID)

    D5862 Test Method for Evaluation of Engine Oils in Two-Stroke Cycle Turbo-Supercharged 6V92TA Diesel Engine

    D6202 Test Method for Automotive Engine Oils on the Fuel Economy of Passenger Cars and Light-Duty Trucks in the Sequence VIA Spark Ignition Engine

    D6594 Test Method for Evaluation of Corrosiveness of Diesel Engine Oil at 135 C

    D7422 Test Method for Evaluation of Diesel Engine Oils in T-12 Exhaust Gas Recirculation Diesel Engine

    E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

    SAE Standard

    API Standard

    ICS Code

    ICS Number Code 75.100 (Lubricants, industrial oils and related products)

    UNSPSC Code

    UNSPSC Code 15121501(Engine oil)

    Referencing This Standard

    DOI: 10.1520/D6750-15A

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM D6750-15a, Standard Test Methods for Evaluation of Engine Oils in a High-Speed, Single-Cylinder Diesel Engine—1K Procedure (0.4 % Fuel Sulfur) and 1N Procedure (0.04 % Fuel Sulfur), ASTM International, West Conshohocken, PA, 2015,

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