Safe at the Pump?

E10 won’t stop you from using your collector vehicle, but you’ll have to be more vigilant about fuel system maintenance.

Carburetors didn’t turn to dust. Fuel pumps didn’t grind to a halt. Gaskets and seals didn’t melt into mushy goo. After 1,500 hours of testing six different automobile fuel systems on both E0 (straight gasoline) and E10 (gasoline with 10 percent ethanol) at Kettering University, disaster didn’t reign. When discussing the results of the Hagerty-funded research, Kettering professor Dr. Greg Davis remarked, “We can find no evidence that there is any significant danger to the health of the fuel system components associated with E10.”

To the test

As recounted in the Spring 2009 issue of Hagerty’s, “Ethanol: Demonic or Divine,” the Kettering team devised a set of tests to determine the effects of E10 on fuel system components.

In one set of tests, new or freshly rebuilt pairings of carburetors and fuel pumps were set up to mimic their operation in a vehicle. In another set of tests, sections of the fuel system were ultimately exposed to fuel and allowed to dry. In all cases, two sets of components were tested: one exposed to E0 and another to E10. Fuel systems from six cars were selected: 1948 Flathead Ford, 1958 Volkswagen Beetle, 1962 MG, 1963 Ford Falcon, 1969 Chevrolet Bel Air and 1970 Chrysler New Yorker.

The carburetor-fuel pump combination on the ’62 MG was the first to complete testing. There was some minor particle buildup, gum and tar deposits and minor corrosion visible on the components run on E10. However, at the end of the test, both the carbs and the fuel pumps were flowing fuel without any leaks or reduced performance.

Now, the results are in for the other five fuel systems tested. The most visible change was that several pump and carburetor bodies appeared to be discolored. Upon close examination, the change in hue was simply staining, most likely due to the aging fuel that darkened as the more volatile gases evaporated when remaining fuel oxidized. As with the SU carburetors, several other carburetor components showed some minor gum buildup. At the conclusion of the test, the pumps were still pumping like new and the carburetors were free of leaks or significant particle deposits. It was clear that in the test of both the straight gasoline and E10, seals were constantly swelling when wet and contracting as they dried.

Other effects of E10

With the greater solvency and drying effect of the ethanol, it’s likely that there will be a shorter life cycle of seals used with E10, although at the conclusion of these tests, no damage was visible. As a precaution, fuel systems that haven’t been rebuilt recently or have unknown history should be rebuilt with new seals, gaskets or soft lines made of modern materials, such as Viton and Nitrile, to ensure compatibility of materials with ethanol and to reduce the chance of failure or fire.

Fuel system consultant Michael Harrigan of Zen Fuel LLC agrees that it’s critical to use modern materials and would replace any natural cork or paper gaskets with materials made of Nitrile Butyl Rubber (NBR) and “avoid any type of natural rubber, neoprene rubber or silicone rubber.” Dr. Gary Mead, the technical lead on the E0, E10 and E20 study by Minnesota State University, Mankato, agrees with Harrigan on the avoidance of these rubber components.

Over many years varnishes and sludge build up in fuel systems. As a solvent, ethanol loosens these deposits, which are then carried by fuel flow. As a result, the most common problems owners of old vehicles experience when switching from E0 to E10 consist of blockages of fuel lines, pumps, filters and injectors, especially in vehicles that haven’t had their fuel systems (including the gas tank) cleaned and rebuilt with new soft parts.

However, thanks to ethanol, some of the used parts tested were actually cleaner upon conclusion of the test than when the trials began. When ethanol is first used in an older car, the owner initially may need to change fuel filters more frequently; rubber seals and gaskets may require more frequent replacement.

Zen Fuel’s Harrigan and Minnesota State Mankato’s Mead agree that the fuel systems of many older vehicles should not be jeopardized by E10 – assuming that modern seals, gaskets and lines are used. They assert, however, that ethanol-blended fuel results in leaner-burning combustion than gasoline. The leaner mixture usually increases combustion and exhaust temperatures, which are detrimental to engine durability. That means that when using ethanol-blended fuels, the vehicle should be tuned to prevent a lean mixture and the corresponding damage that may result. This is especially important since many antique and classic cars lack oxygen sensors and cannot compensate for the leaner-burning fuel.

Looking to the future

With this new insight into the effects of E10 on older vehicles, what about higher ethanol blends? According to Dr. Steve Przesmitzki of the Fuels Performance Group of the National Renewable Energy Lab, many government organizations – including the Department of Energy, Environmental Protection Agency and California Air Resource Board, along with auto manufacturers, oil companies and other equipment manufacturers – currently are investigating the use of 15- and 20-percent blends of ethanol in vehicles already on our roads.

In addition to being a solvent that can degrade rubber, ethanol has a much higher electrical conductivity than gasoline and can promote galvanic corrosion and oxidation in a variety and combination of metals. In fuels with low concentrations of ethanol, the Hagerty-funded study showed that these effects are minimal. Although low-level ethanol blended fuels don’t pose immediate and dire threats to many older vehicles, it isn’t yet known what the effects of higher percentages of ethanol will be on vehicles built many years ago.

According to tests funded by the State of Minnesota and conducted by Minnesota State Mankato, neither E10 nor E20 had any detrimental effect on components of new vehicles — as well as those built in the last three decades. However, according to many within the industry, further tests are needed to monitor the long-term effects of ethanol on components in the large number of cars that are more than a few years old.

As both the ethanol industry and many in Washington continue to call for widespread use of E15 or E20, the National Renewable Energy Lab and Oak Ridge National Lab (Department of Energy Labs) are working with industry stakeholders – including the Coordinating Research Council (auto and oil companies) and the American Petroleum Institute – in conducting studies to examine the long-term effect of mid-level ethanol blends on both new cars and those that have already been in service for up to 10 years.

If additional funding can be obtained, there is interest in extending the study to include older vehicles. Przesmitzki is concerned that collector vehicle owners will be able to continue operating their vehicles without unintended damage. He does, however, have an ulterior motive. “If there are problems, I’m the one who will have to fix my mother-in-law’s old MG.”
To see this article in its original format, view the pdf version of the Fall 2009 issue of Hagerty magazine.

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