Development of the PV-2 Engine Deposit and Wear Test-An ASTM Task Force Progress Report 872123

An ASTM Task Force was formed in 1979 to improve the discriminatory abilities for engine sludge deposits and valve train wear of the ASTM Sequence V-D test. Several statistically designed programs were conducted to identify procedural and hardware items to achieve the stated objectives. The 2.3 liter, four cylinder test engine was updated with electronic fuel injection and high swirl combustion chamber technology. Of the parameters evaluated, increased test length, adjustments of temperatures and control of the rocker cover temperature had the greatest impact on increased test severity.

A procedure has been developed that better discriminates between known good and poor engine oils. Field correlation has been improved and expanded to include European experience. An extensive program has been planned to establish field correlation and test precision.

THE AMERICAN SOCIETY OF TESTING AND MATERIALS (ASTM) D02.B0.01 SEQUENCE V-D SURVEILLANCE PANEL was directed by the ASTM Oil Classification Panel to improve the Sequence V-D test discrimination at the time this test was accepted for the American Petroleum Institute (API) SF category. The Surveillance Panel established the Sludge and Wear Task Force to improve discriminatory capabilities with respect to engine sludge deposits and valve train wear. Lacking the required severity in these two areas, it was necessary to pursue means to modify the Sequence V-D procedure (1)* to obtain a severity level which would better discriminate between field oils. Since 1979, nine programs have been conducted in an effort to identify test parameters which have the most influence on engine deposits and valve train wear. Appendix A lists the highlights of these programs. This paper reviews the effect that certain parameters evaluated in these programs had on engine deposits and valve train wear. The final form of the PV-2 procedure reported in this paper has not been accepted, either for information or as a standard, for use by ASTM and is subject to change.

An increase in field sludge problems has been reported over the last five years under European driving conditions and severe service in North America (2)(3). European and domestic original equipment manufacturers reported severe sludging with API SF/CC oils using drain intervals as short as 1,000 miles. Oil delivery systems have become blocked with sludge deposits, resulting in camshaft failures. Taxi and police service have shown greater levels of sludge. Results from several European police fleets were alarming. Oils with inadequate performance were being used in field service as shown in Table 1 (4). The need for improved discriminatory abilities of the Sequence V test was evident.

Abbreviations used throughout this paper are summarized at the end of this paper.