Crankcase blow-by is hot gases that sneak past the piston rings. As of 2007, the U.S. Environmental Protection Agency limits nonmethane hydrocarbons to 0.14 grams per bhp-hr. Blow-by gases are rich in ...

Every engine has some sort of crankcase breathing system. The internal combustion process creates pressure, some of which makes its way past the piston rings-along with fuel vapors-and into the rest ...