1971-02-01

Valve Problems with Lead Free Gasoline 710368

Use of lead free gasoline results in severe exhaust valve recession in light duty engines. Recession proceeds 10-20 times faster than with leaded fuel, and occurs on the integral cylinder head seats. A wear model is proposed which identifies parameters contributing to recession. Engine tests showed valve seat angle and cylinder head seat hardness and/or structure to be most significant in reducing seat wear. Coatings, wider seats, and improved valve train stability all show plus effects but were insufficient by themselves to stabilize wear rates. Wide seats, use of seat inserts, and lower seat angles resulted in shortened valve burning life in engines run with leaded gasoline. Induction hardened cylinder head seats reduced wear with no effect on valve durability.

SAE MOBILUS

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

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
JOURNAL ARTICLE

Prediction of Wear Loss of Exhaust Valve Seat of Gasoline Engine Based on Rig Test Result

2018-01-0984

View Details

TECHNICAL PAPER

The Effect of Some Fuel and Operating Parameters on Exhaust Valve Seat Wear

710673

View Details

TECHNICAL PAPER

Influence of Low Lead Fuels on Exhaust Valve Performance

710674

View Details

X