If you've been walking the planet for any time at all, you're familiar with the energy challenges we've been facing since the mid-'70s. Prior to 1974, gasoline was plentiful and cheap as we pumped it into our classics at 23 cents per gallon. Some of you remember gas wars, when service stations priced gasoline so low that they nearly paid us to pump it. When I came of age, you could fill your tank and cruise all night for $4 bucks.
All that cheap and plentiful gasoline went away in the winter of 1973-'74, when the Arab Oil Embargo doubled fuel prices overnight. Many gas stations ran out. We faced long lines and waited hours to get gas. Some states initiated odd/even license plate days (last number) where you were only permitted to buy gas on your day. Unfortunately we didn't see the energy crisis coming, but when it arrived, it was a sobering event.
For 35 years, we've had it drummed into our heads to be less dependent on foreign oil, yet we're still in denial, as we continue to pump petroleum into our automobiles. To reduce consumption of crude and improve exhaust emissions, oil companies have whipped up all kinds of different gasoline cocktails through the years. One such additive is ethanol; you've no doubt seen the signs on the pumps advising that the fuel contains 10 percent ethanol.
Before ethanol, the oil companies oxygenated fuel with MTBE (methyl tertiary-butyl ether), a chemical compound that comes from a reaction between methanol and isobutylene. It is quite volatile with a high evaporation rate. However, when it was learned MTBE was hazardous to ground water supplies the EPA mandated alternatives, such as ethanol.
So aside from obviously using less petroleum, why mix ethanol with gasoline? Ethanol, also called ethyl alcohol or grain alcohol, adds oxygen to reduce air pollution. Available heat energy from ethanol also makes it a good octane enhancer. As such, we can bump the compression ratios a little higher to achieve more power, without detonating an engine to death. That's the good news.
The bad news is the detrimental side effects of ethanol in gasoline when used in older cars. Ethanol is especially hard on classic cars, with their rubber fuel hoses, rubber fuel pump diaphragms, carburetor float needle valves, cork and rubber gaskets, galvanized fuel tanks and fuel lines, and other related components. Some owners have even reported problems with phenolic carburetor floats. Ethanol also tends to be hard on die-cast carburetor bodies, which calls for close inspection of the metal carb parts, because ethanol and zinc don't get along well. Although ethanol probably won't harm your carburetor's metal parts, there's always some element of risk, depending on your carburetor's metallurgy.
Another known ethanol issue is water retention. Like brake fluid, ethanol likes to retain more water then gasoline. Because ethanol tends to be hard on rubber and cork components, you can wind up with leaks and bits of rubber in the fuel system, which can cause a sticking float and plugged passages. This is why visually inspection of fuel bowls is important from time to time.
While the jury remains out on the adverse effects of pumping E10 (90-percent gasoline and 10-percent ethanol) into our classics, E85 (85-percent ethanol and 15-percent gasoline) should never be used in a classic car.
In the good old days of high-octane leaded fuel, it was easy to overlook the inspection of fuel system components, as these items deteriorated slowly, requiring only periodic maintenance. However because ethanol accelerates the deterioration of vintage fuel system components, preventative maintenance is required on a regular basis. Neglect them today and it can bite you, with fuel leakage and/or the potential for fuel-related fires, which have become a problem with the older fuel systems on our classic cars.
Regular Preventative Maintenance for Vintage Carburetors
Because there isn't a carburetor kit designed for today's harsher fuels, you must inspect and service your fuel system more often than you used to. All fuel system rubber parts should be inspected frequently, and replaced annually at a minimum. Below is a list of inspection checks, which should be done every six months.
- Inspect the carburetor externally for fuel leaks (accelerator pump and power valve).
- Look for leakage around the throttle shaft.
- Remove the air horn and inspect both float and needle valve.
- Examine carburetor internals for evidence of leakage from a sticking float.
- Inspect throttle plates for evidence of fuel dribbling.
- Work the throttle and check accelerator pump shot quality.
Fuel filler hoses seem to be more resistant to ethanol fuel and today's fuel additives because we haven't seen them break down nor heard any complaints from our readers about them. However, we suggest regular inspection and replacement.
If your Mustang has its original fuel tank, we suggest replacement with a galvanized tank designed to stand up to ethanol fuels. Scott Drake Enterprises has introduced a line of stainless steel fuel tanks for classic Mustangs. They are impervious to all kinds of fuels and additives.
Stainless steel fuel line is resistant to all kinds of fuels and additives, making your fuel system exceptionally safe against ethanol fuels. Where possible, run 100-percent stainless fuel line from tank to carburetor. Use stainless steel braided fuel hose and industrial grade clamps where you can't.
When authenticity is important, you want original equipment fuel hoses. However, you must change fuel system hoses as inspection warrants. If authenticity isn't important, opt for high-pressure fuel injection hose instead, which will fit your 5/16- or 3/8-inch fuel lines and will stand up to today's fuels. Although conventional worm-gear clamps are normally used, we suggest heavy-duty industrial clamps in the interest of safety.
Because ethanol burns more quickly, yielding less heat energy, carburetor jetting may have to change depending on where you live. Because we have to throw more ethanol at the engine to get the same amount of heat energy, jetting may need to be richer.
Float Needle Valve
Don't be surprised if you need to replace the float needle valve every six to 12 months. Frequency depends on kit quality and material used.
Several companies build ethanol-ready carburetors (meaning E10, not E85) fitted with components designed to endure today's ethanol fuels. This may be a good option for your daily driver or weekend cruiser.
Sta-Bil Fuel Stabilizer now comes in a new and improved formula for those with weekend cruisers that collect a lot of garage dust. It reduces gum and varnish deposits, and controls water retention caused by ethanol. Sta-Bil is available at Auto Zone.