Gasoline Ethanol Blends and the Classic Auto
(Renewable Fuels Association) The ongoing effort to alter gasoline to minimize its impact on the environment and reduce U.S. dependence on foreign crude oil has refocused attention on fuel quality issues. The increased use of ethanol, now in well over 90 percent of the nation’s gasoline, has prompted questions and sometimes raised concerns with the antique auto community. For the owner of a classic automobile that question is whether today’s fuels will work in yesterday’s automobiles.
Owners of classic vehicles have unique considerations: the vehicle’s fuel system may differ significantly from that of modern cars; the vehicle usually is not driven often and is stored for long periods; and the vehicle probably operates rich at specified air/fuel settings compared to modern cars. In the case of “muscle cars,” the compression ratio may dictate the use of very high octane gasoline and, if the valve seats are not hardened, the effect of unleaded gasoline with, or without ethanol, on exhaust valve seats may be an issue.
Editor’s note: If you don’t own a classic car, but just want a fairly simple explanation of things like octane, fuel oxygenates, phase separation, engine knock, fuel volatility, compression ratios, winter grades and summer grades, enleaning, etc., that are important in understanding how fuels and engines work together, this is a good, relatively quick, read, along with the Petroleum Production, Distribution and Discussion of the use of Ethanol Blended Gasoline paper.