There some big problems when you start to compare the operation of a car engine to a airplane engine. The operating enviroment, the loads the engine has to substain, even the material the fuel tanks are made of are different.
Around 1972, the auto makers began to design their engines to use a gas/alcohol blend. Auto engines(carbs especially) designed before that time may or may not have problems. I was a BMW, Fiat, VW mechanic working my way through college during that era. I have seen first hand that gasahol distorted plastic carb floats, carb gaskets, and even rubber fuel lines. I have changed clogged fuel filters and fluched fuel lines of mid 1960s cars after the owner decided after 10 years of gasoline use, to switch and try gasahol. The alcohol dissolved some old sludge in the bottom of the tank and plugged the filter Later I taught vocational power mechanics and witnessed gasahols effects on rubber carb diaphrams used in lawn and guarden equipment. I am happy that many of our members have had sucess in using gasahol in their post 1972 autos, I have too. But we need to compare our apples to apples and focus on aviation engines. I have a STC to burn mogas in my Cessna and I use it. I burn a mix of 3 parts mogas (no alcohol) to 1 part 100LL avgas. 100LL avgas contain 4 times the lead content of the 80 octane leaded avgas that is no longer available. This mixture is my effort to duplicate the lead content of the fuel my engine was designed to use. I am attemping to reduce the lead deposits on my spark plugs and other internat engine surfaces. Brant Hollensbe Bhollensbe at mchsi.com West Des Moines, Iowa
