Influence of Low Lead Fuels on Exhaust Valve Performance 710674

An extensive series of tests has been completed to evaluate accelerated exhaust valve seat wear which occurs in passenger car engines with lead-free gasoline. Results indicate that the predominate factor contributing to seat recession is vibration induced relative motion between the valve and seat. Engine speed rather than load or temperature showed the greatest influence on accelerated wear. Various combinations of valve head shape including changes in seat angle, seat width, and valve head stiffness were studied. Fixed versus rotated valves, various valve materials, and face coatings and fuel additive evaluations also were made. Reduced valve seat angles and hardened seats showed the greatest reduction in valve seat wear with lead-free gasoline.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 40% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.