"Tony Cox" wrote in message nk.net...


Any idea what the additives in 100W+ are, Aaron? I suppose
one day I ought to find out why I'm paying an extra $0.50/qt
over straight 100W. Perhaps that day has come!

The Lycoming anti-wear additive. Used to be TCP (Tri-Cresyl Phosphate)
until a few years ago when it was changed to TPP (Tri-Phenyl
Phosphate) when it became widely known that TCP was an extremely
neurotoxic poison that rapidly absorbs thru your skin. TPP is somewhat
less dangerous than TCP and works almost as well for protecting
against premature lifter/cam lobe wear.

Yes, this is the same TCP or TPP chemical that used to also be used as
a fuel additive to help prevent lead deposits from sticking the
valves, but has become virtually impossible to buy anymore.