Quote:
Originally Posted by order99
Regarding the two-stroke...all the research i'm doing lately (rebuilding an antique chainsaw motor with hand tools for the experience) indicates that Ethanol blends can damage the motor. Since your personal experiences suggest otherwise, i'd be interested in all the details, gory and otherwise...any issues with proper mixing of gas/oil/ethanol, maximum safe and most efficient dosages,effects on power, possibility of timing/detonation issues, effect on emissions etc etc.
The subject of my inexperienced (and therefore possibly gruesome) experiment is a late 1950-something Rolan 'Heavy Hauling' chainsaw made in Sweden, probably 40cc to 50cc with a broken starting spring and the chain installed backwards-quite possibly the reason I snagged it for $2.00!  If I don't turn this lovely antique into twisted metal through my own incompetence I intend to ditch the blade and create a small, potent portable plant that I can bolt to a generator, lightweight recumbent trike platform and/or tiny personal watercraft...or just watch it spin... |
When pure ethanol started to be used in Brazilian cars, the most usual caution was to coat the internal parts of the carburettor with 2 lays of chrome to prevent them to rust, and even in 4-stroke engines some folks started to add 2% of oil in the gasoline (due to the locally-mandated ethanol blend) to protect the carburettor's needle. And 4-stroke engines were a different animal, since due to the absence of either leadtetraethyl or lately MTBE, valve seat inserts had to be hardened, while this issue didn't affect 2-stroke since there is no valvetrain at all. And even before ethanol became mainstream for cars back here, it was already widely used for kart-racing.
The oil blends in ethanol and gasoline are usually different, with more oil added to the gasoline than to the ethanol due to the consumption in volume for each fuel, higher on ethanol, thus using basically the same amount of oil regardless the fuel in use. 5 to 7% in volume is the most efficient blend of oil, altough some newer synthetic oils allow a lower blend, around 2 to 3%. Castor-based oils mix more homogeneously with the ethanol than petroleum-based ones.
When you quote timing and detonation issues, I presume you're talking about ignition timing. It's usually advanced a few degrees due to the lower flame spreading speed in the ethanol than in gasoline. But depending on how much the compression is raised, in an engine with individual displacements below 250cc for each cylinder, it's not much an issue.