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An Overhead Cam Wear and Valvetrain Dynamics Study
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English
Abstract
A 22 hour engine test was developed to evaluate the effects of fuels, lubricants, and valvetrain dynamics on the wear of OHC 2.3L engine camshafts and finger followers. Procedures include a break-in to improve test repeatability and a test sequence to allow single-shift operation. A surface analyzer capable of measuring cam lobe wear profiles to micro-inch accuracy provided a quantitative wear comparison.
A pure mineral oil, as expected, resulted in higher camshaft wear than using a fully formulated SF lubricant. Cam and follower wear increased significantly when ethanol replaced gasoline as fuel. The combination of ethanol, mineral oil and heavy duty valve springs was selected to increase test severity for hardware discrimination.
The average wear of the intake lobes was greater than the exhausts. Kinematic analysis and visual inspection of the valve train mechanism revealed differences in the relative motion and contact stress pattern. Insufficient hydrodynamic oil film, long duration of high contact stress and entrapment of abrasive particles appear to cause increased wear. Methods to reduce cam wear are suggested.
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Citation
King, E. and Chul, G., "An Overhead Cam Wear and Valvetrain Dynamics Study," SAE Technical Paper 892149, 1989, https://doi.org/10.4271/892149.Also In
References
- Chui, G. K. Baker, R. E. “Lubrication Behavior in Ethanol-Fueled Engines” 4th Symposium on Alcohol Fuels Guaraja, Brazil October 1980
- Chui, G. K. King, E. T. Groff, W. P. “Modified Sequence V-D Test with Two Engines Using Alcohol Fuels” SAE Paper 830239 1983
- Chui, G. K. King, E. T. Pedrys, F. “Evaluation of Lubricants For Methanol-Fueled Engines” Proceedings Fifth International Alcohol Fuel Technology Symposium II Auckland, New Zeland May 13-18 1982
- Chaibongsai, S. et al Paramins Technology Division; “Development of an Engine Screening Test to Study Effects of Methanol Fuel on Crankcase Oils” SAE Paper 830240 1983
- Marbach, H. W. et al Southwest Research Institute “The Effects of Alcohol Fuels and Fully Formulated Lubricants on Engine Wear” SAE Paper 811199 1981
- Ryan, T. W. III et al “The Mechanism Leading to Increased Cylinder Bore and Ring Wear in Methanol Fueled S.I. Engines” SAE Paper 811200 1981
- Baisley, W. H. Edwards, C. F. “Wear Characteristics of Fleet Vehicles Operated on Methyl Alcohol” SAE Paper 811202 1981
- Baisley, W. H. Edwards, C. F. “Emission and Wear Characteristics of an Alcohol Fueled Fleet Using Feedback Carburetion and Three-Way Catalysts” 4th Symposium on Alcohol Fuels Guaraja, Brazil October 1980
- Naman, T. M. Streigler, B. “Engine and Field Test Evaluation of Methanol as an Automotive Fuel” SAE Paper 831703 1983
- Dyson. A. “Kinematics and Wear Patterns of Cam and Finger Follower Automotive Valve Gear” Triboiogy International June 1980
- Morgan, J. A. Stojeck, D. J. “European Ford 4 Cylinder In-Line Single OHC Engines” Institute of Mechanical Engineers Conference Publication 19 1973
- Miorali, M. Chiarottino. A. “Engine Valve Train WeanPerformance of Synthetic and Mineral Oils” SAE Paper 811226 1981
- Staron, J. T. “1.6L/2.3L Valve Train Friction” Ford Worldwide Technical Exchange Seminar, Engine Friction AEEO June 1982
- Staron, J. T. Willermet, P. A. “An Analysis of Valve Train Friction in terms of Lubrication Principles” SAE Paper 830165 February 1983
- Muller, R. “Der Einfluss der Schmiervoerhaltnisse am Nockentrieb” MTZ 1966 27 58
- Purmer, P. D. van den Berg, W. “Measurement of Camshaft Wear - Wear & Kinematics of Overhead Camshafts” KONINKLIJKE/SHELL-LABORATORIUM Amsterdam Shell Research B.V.
- Bell, J. C. Colgan, T. A. “Pivoted-Follower Valve Train Wear: Criteria & Modeling” Shell Research LTD., Thornton Research Centre P.O. Box 1, Chester CH1 3SH STLE-ASME Triboiogy Conference Fort Lauderdale October 1989