Living with Ethanol

How to make blended fuels work with your old car


As if classic car owners didn’t suffer enough with the demise of leaded gas, now we’ve got ethanol to fret over. While gasoline-ethanol blends, originally called gasohol, have been around since 1978, they’re now so prevalent we’re stuck pumping the stuff into our tanks.

A 2009 survey conducted by Hagerty revealed that 91 percent of the respondents were down on the idea of blended gas, and 29 percent reported problems attributable to the use of E10, a 10/90-mix of ethanol and gasoline.

Ethanol does have positive attributes. The government mandates its use because it lowers both greenhouse gas emissions and petroleum imports. Ethanol also boosts octane — good news for muscle car and hot rod owners.

The bad news is that ethanol’s energy density is lower than gasoline, so mileage is slightly poorer with the now-common E10 and the coming E15 (15 percent ethanol) blends. Because ethanol is an aggressive solvent, it can dislodge fuel system deposits, resulting in clogged filters and screens. Its galvanic action can also corrode unprotected steel fuel tanks. Worse, ethanol absorbs water from the air, and it’s hostile to fiberglass, two reasons why boaters hate the stuff. E10 is illegal for aviation use.

To understand what we’re getting into here, Hagerty collaborated with Kettering University on an in-depth E10 study. Some 3,000 hours of testing revealed that ethanol won’t dissolve your carburetor or fuel pump while you watch. As long as an extra measure of preventative care is exercised, classic car owners should be able to survive the blended-fuels era without calamity.

Shrewd preventative maintenance starts by keeping a watchful eye on fuel filters. Because cork, paper, natural rubber, neoprene rubber and some silicone materials are vulnerable to the ill effects of ethanol, when it’s time to overhaul your carburetor, rejuvenate your fuel pump, or service your tank and lines, it’s essential to use modern gaskets, seals, coatings and hose materials compatible with today’s fuel. It’s also a good idea to brush up on your spark plug-reading skills: While modern cars self correct for the slightly leaner fuel-air mixtures inherent with E10, old cars may require carburetor jet changes to run perfectly on this fuel.

Short of constructing your own refinery, there are fuels such as VP Racing Gas that contain no alcohol. VP’s C9 storage fuel guards against gas-water phase separation and jet clogging during winter months. Additives such as Marvel Mystery Oil and Sta-Bil have also earned a devoted following among car collectors. The only way you’ll know what works best in your car is to experiment with the products we’ve listed here.

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