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.

Ford's 6.2L Boss engine was supposed to be the future of its larger engines. Instead, it's now known for a slew of problems ...

I bought a 1969 Chevrolet Chevelle SS 396 recently and want to know if unleaded gas will harm my engine. Also, will using regular unleaded instead of high-octane unleaded hurt? I’d rather use the less ...

Valve seat wear or "sinkage" or "recession" was observed in eight engines run on unleaded fuel. Detailed studies of valve seat wear were undertaken in a 302 cu in. V-8 engine run for 10-1/4 hr at WOT ...

General Motors's Active Fuel Management (AFM) technology utilizes hydraulic valves, solenoids, and advanced software to shut down half of the cylinders in a V8 or V6 engine to save fuel. The system ...

Does your engine need a valve adjustment? It depends on the age, condition and brand of vehicle you’re driving. Due to the popularization of roller-follower valve train designs that reduce friction ...

Evan Williams is an automotive journalist and mechanical engineering technologist with more than a decade of experience in the industry. He has written for the Toronto Star and AutoTrader Canada and ...