Coping Without Leaded Gas


| October/November 1992



HC 89, Box50B, Eden, Texas 76837

If you own a gasoline engine manufactured before 1974, it probably was designed to use leaded gasoline.

Since 1986, EPA regulations have reduced the amount of lead that a refiner can add to gasoline by 91%, from 1.1 grams per gallon to 0.1 gpg. That leaves older and industrial-type engines, such as those used by many farmers, without protection against valve damage.

However, some gasoline engines made as early as 1971 were built with hardened valves and valve seats that are not affected by unleaded fuel. And most vehicle engines made after 1974 have hardened valves.

Engines designed to run on leaded gas have soft valve seats, specially designed for use with leaded fuel. These engines were designed to use leaded gas to lubricate exhaust valves. The lead is most important when an engine is running at high speed under a heavy load.

Even leaded fuel that meets the new requirements is getting harder to find. To avoid stiff penalties and fines for exceeding the EPA's standard, many refiners are keeping lead in gasoline blends well below the permitted level. In fact, only traces of lead are present in many 'leaded' fuels, making some companies' leaded and unleaded products virtually identical.