EFFECT OF ENGINE OIL ZINC DITHIOPHOSPHATE (ZDP) ADDITIVE TYPE ON CAM AND LIFTER WEAR IN TAXI SERVICE

The major phosphorus-containing compounds in engine oil are zinc dithiophosphates (ZDP's), which act both as antioxidants and antiwear agents. To reduce engine oil phosphorus concentrations without compromising engine durability, and thereby reduce phosphorus poisoning of emission control devices, an optimum ZDP mixture should be used. A 160,000-km taxi test was conducted to determine the relative camshaft and lifter wear protection provided by several ZDP's and ZDP mixtures. Wear protection was poorest with aryl ZDP's (which are thermally stable, as determined by differential scanning calorimetry (DSC)), intermediate with long-chain primary alkyl ZDP's (which are thermally unstable), and best with short-to-medium chain secondary or short-chain primary alkyl ZDP's (which are of intermediate thermal stability). Sequence IIID test results on analogs of the field test oils correlated fairly well with taxi test results; sequence V-D test results did not correlate as well.

  • Availability:
  • Supplemental Notes:
    • Reprinted from SP-558 Lubricant and Additive Effects on Engine Wear. Fuels and Lubricants Meeting San Francisco, California, October 31-November 3, 1983.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • Smolenski, D J
    • Kabel, R H
  • Publication Date: 1983

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 16 p.
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00387430
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: SAE 831760 Reprint, HS-036 787
  • Files: HSL, USDOT
  • Created Date: Aug 30 1984 12:00AM