Was thinking about marvel mystery oil


Well-Known Member
TCP in it is good for cleaning engine valves, used to be in better grades of gasoline, and
I add it to aircraft fuel when I have to burn 100 octane "low lead" which may be lower
that the old 145 octane aircraft fuel but is still high in lead, and the lead goops the exhaust valve
stems on engines designed for 80 octane (no lead, always). After one very successful
off-airport emergency landing due to stuck exhaust valves because of 100 LL fuel, I am
very cognizant of this issue. So, TCP is for the valves, not sure if it has any benefits in cleaning

IIRC, it is also an extreme pressure lubricant, good for normal flat lifter camshafts. It's
absence in oil today (to protect catalyst) has pushed the switch to roller lifters on most
modern cars.

Last edited: