ASTM D 8256a:2024

1.1 This test method is commonly referred to as the Sequence VH test, and it has been correlated with the Sequence VG test. The Sequence VG test was previously correlated with vehicles used in stop-and-go service prior to 1996, particularly with regard to sludge and varnish formation. 3 It is one of the test methods required to evaluate oils intended to satisfy the API SN, SN Plus performance category. 1.2 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.2.1 Exception- Where there is no direct SI equivalent such as screw threads, national pipe threads/diameters, tubing size, or specified single source equipment. 1.3 A table of contents follows: Section Scope 1 Referenced Documents 2 Terminology 3 Summary of Test Method 4 Significance and Use 5 Apparatus (General Description) 6 Apparatus (The Test Engine) 7 Sequence VH Test Engine 7.1 Required New Engine Parts 7.2 Reusable Engine Parts 7.3 Specially Fabricated Engine Parts 7.4 Special Engine Measurement and Assembly Equipment 7.5 Miscellaneous Engine Components-Preparation 7.6 Solvents and Cleaners Required 7.7 Assembling the Test Engine-Preparations 7.8 Assembling the Test Engine-Installations 7.9 Engine Installation on the Test Stand 7.10 Engine Fluids (Supply/Discharge Systems) 8 Intake Air 8.1 Fuel and Fuel System 8.2 Engine Oil and Engine Oil System 8.3 Coolants 8.4 Measurement Instrumentation 9 Temperatures 9.1 Pressures 9.2 Flow Rates 9.3 Fuel Consumption 9.4 Speed and Torque 9.5 Exhaust Gas 9.6 Humidity 9.7 Miscellaneous Laboratory Equipment 10 Test Stand Calibration 11 Test Procedure 12 Pre-Test Procedure 12.1 Engine Operating Procedure 12.2 Periodic Measurements and Functions 12.3 Special Maintenance Procedures 12.4 Diagnostic Data Review 12.5 End of Test Procedure 12.6 Interpretation of Test Results 13 Parts Rating Area-Environment 13.1 Sludge Ratings 13.2 Varnish Ratings 13.3 Clogging 13.4 Sticking 13.5 Used Oil Analyses 13.6 Assessment of Test Validity ...

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