ASTM D6891 Standard Test Method for Evaluation of Automotive Engine Oils in the Sequence IVA Spark-Ignition Engine
1. Scope
1.1 This test method measures the ability of crankcase oil to control camshaft lobe wear for spark-ignition engines equipped with an overhead valve-train and sliding cam followers. This test method is designed to simulate extended engine idling vehicle operation. The Sequence IVA Test Method uses a Nissan KA24E engine. The primary result is camshaft lobe wear (measured at seven locations around each of the twelve lobes). Secondary results include cam lobe nose wear and measurement of iron wear metal concentration in the used engine oil. Other determinations such as fuel dilution of crankcase oil, non-ferrous wear metal concentrations, and total oil consumption, can be useful in the assessment of the validity of the test results.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.2.1 Exceptions - Where there is no direct SI equivalent such as pipe fittings, tubing, NPT screw threads/diameters, or single source equipment specified.
1.3 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. See Annex A9 for specific safety precautions.
2. Referenced Documents
2.1 ASTM Standards:
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)
D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)
D381 Test Method for Gum Content in Fuels by Jet Evaporation
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
D525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)
D3525 Test Method for Gasoline Diluent in Used Gasoline Engine Oils by Gas Chromatography
D4485 Specification for Performance of Active API Service Category Engine Oils
D5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
D5844 Test Method for Evaluation of Automotive Engine Oils for Inhibition of Rusting (Sequence IID) (Withdrawn 2003)
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
2.2 API Standard:
API 1509 Engine Oil Licensing and Certification System
2.3 SAE Standards:
SAE J183 Engine Oil Performance and Engine Service Classification
SAE J254 Instrumentation and Techniques for Exhaust Gas Emissions Measurement
2.4 ASME Standard:
B46.1 Standard for Surface Texture (Surface Roughness, Waviness, and Lay)
2.5 JASO Standard:
M 328-95 Valve-train Wear Test Procedure for Evaluating Automobile Gasoline Engine Oils
2.6 CEC Standard:
CEC-L-38-A-94 Peugeot TU-3M/KDX Valve-train Scuffing Wear Test
3. Terminology
3.1 Definitions:
3.1.1 blowby, n - that portion of the combustion products and unburned air/fuel mixture that leaks past piston rings into the engine crankcase during operation.
3.1.2 calibration test stand, n - a test stand on which the testing of reference material(s), conducted as specified in the standard, provided acceptable results.
3.1.2.1 Discussion - In several automotive lubricant standard test methods, the ASTM Test Monitoring Center provides testing guidance and determines acceptability.
3.1.3 reference oil, n - an oil of known performance characteristics, used as a basis for comparison.
3.1.3.1 Discussion - Reference oils are used to calibrate testing facilities, to compare the performance of other oils, or to evaluate other materials (such as seals) that interact with oils.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 assessment length, n - the length of surface over which measurements are made.
3.2.2 break-in, n - initial engine operation to reach stabilization of the engine performance after new parts are installed in the engine.
3.2.3 cam lobe wear, n - the sum of the wear determined at the following locations (nose is zero location): (1) 14 cam degrees before the nose, (2) 10° before the nose, (3) 4° before the nose, (4) at the nose, (5) 4° after the nose, (6) 10° after the nose, (7) 14° after the nose.
3.2.4 cam nose wear, n - the maximum linear deviation of a worn nose profile from the unworn profile; the nose is the high lift point on the particular cam lobe.
3.2.5 flushing, n - the installation of a fresh charge of lubricant and oil filter for the purpose of running the engine to reduce and eliminate remnants of the previous oil charge.
3.2.5.1 Discussion - Flushing may be carried out in an iterated process to ensure a more thorough process of reducing previous oil remnants.
3.2.6 reference line, n - a deduced, leveled, straight line drawn on the profilometer graph, from the front unworn average edge of a cam lobe to the rear unworn average edge of that cam lobe.
3.2.7 valve-train, n - a mechanical engine subsystem comprised of the camshaft, the rocker arms, hydraulic lash adjusters, the poppet valves, and valve-springs.
3.2.8 waveness total , n - the maximum excursion of the worn surface as graphically measured normal to the reference line.
