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The Effect of Low Lead Gasolines and Some Aftermarket Lead Substitutes on Exhaust valve Seat Wear
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Abstract
In 1985 the U.S. Environmental Protection Agency instituted regulations which have ultimately limited the lead content of leaded gasolines to 0.1 grams of lead per gallon. There is currently very little test work on the potential for exhaust valve seat recession while running an engine with a cast iron head without hardened exhaust valve seats on gasoline at this lead level. Therefore, we have examined valve seat recession from low lead fuels.
The test program described here evaluates test conditions and additives which can affect exhaust valve seat recession in mid-1960s vintage heads. Cylinder heads produced after the early 1970s had induction hardened exhaust valve seats and were not susceptible to exhaust valve seat recession. Specifically, tests were run in which lead, air/fuel ratio and engine hardware (valve rotators) were varied and evaluated for contribution to the valve recession process. Tests were conducted on fuels which contained lead at 0, 0.05, 0.1, 0.2 and 0.5 grams per gallon to show the effect of low lead fuels on valve recession. Two proprietary aftermarket additives were also evaluated as potential replacements for lead.
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Citation
Croudace, M. and Wusz, T., "The Effect of Low Lead Gasolines and Some Aftermarket Lead Substitutes on Exhaust valve Seat Wear," SAE Technical Paper 872076, 1987, https://doi.org/10.4271/872076.Also In
References
- Environmental Protection Agency “Regulation of Fuels and Fuel Additives; Gasoline Lead Content; Final Rule and Supplemental Notice of Proposed Rulemaking” Federal Register 50 45 9836 9408 March 7 1985
- Environmental Protection Agency “Regulation of Fuel Additives; Banking of Lead Rights; Final Rule.” Federal Register 50 63 13116 13128 April 2 1985
- Doelling R. P. “Engine's Definition of Unleaded Gasoline” SAE Paper No. 710841
- Kent W. L. Finnigan F. T. “Effect of Some Fuel and Operating Parameters on Exhaust Valve Seat Wear” SAE Paper No. 710368
- Giles W. S. “Valve Problems with Lead-Free Gasoline” SAE Paper No. 710368
- Felt A.E. Korley R. V. “Engine and Effects of Lead-Free Gasoline” SAE Paper No. 710367
- Pahnke A. J. Bethany W. E. “Role of Lead Antiknocks in Modern Gasoline” SAE Paper No. 710842
- Schoonveld G. A. Riley R. K. Thomas S. P. Schiff S. “Exhaust Valve Recession With Low Lead Gasolines” SAE Paper No. 861550