European Activity Concerning Engine Oil Viscosity Classification-Part II

This paper is a follow-up to Part 1 of the review on European work in the field of engine oil viscosity relevant to the revision of SAE J 300 classification.

The European activity covers both low and high temperature aspects and is coordinated within C.E.C., Investigation Groups IGL-8 and IGL-9 respectively.

The IGL-8 activity is well under way and results have already been generated in three main areas:

• the replies of the European engine builders to the SAE Questionnaire on low temperature practices and experience have indicated that there is quite a scatter in the low temperature viscometric requirements of different engines similar to that shown in the U.S.A.
• the Borderline Pumping Temperatures determined with four ASTM pumpability reference oils on eight different European engines have shown a wide spectrum of engine sensitivity although the average results are similar to the data generated by ASTM.
• regarding metrication of SAE J 300, European opinion expressed through the C.E.C. National organisations is strongly of the opinion that the 15W grade should be incorporated into the main body of the table and that minimum viscosity values should be assigned to the W grades in order to avoid confusion.

The IGL-9 work on high temperature aspects has concentrated on the viscosity measurements of seven multigrade oils in laboratory apparatus at different temperatures and rates of shear, and the results look encouraging. The next immediate step will concern engine testing of the same reference oils in an attempt to generate information on the behaviour of these lubricants in several high temperature engine performance areas. The completion of this work is necessary before attempting any correlation between practical experience and oil viscosity characteristics as defined in one or more laboratory test methods.