What's the best possible air/fuel mixture? 14.7:1 by weight, known as a "Stoichiometric" mixture. Its only byproducts are CO2 and water vapor, since the carbon atoms in the gas are all converted into CO2, and the hydrogen becomes H2O. Combine CO2 and water vapor in the crankcase from blowby, and you get carbonic acid. (Add a little sugar and caramel color and you get Coca-Cola). If that acidic vapor isn't purged by some type of crankcase vent system, it eats bearings.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!