>On March 9th, Mike wrote: "...Also, am interested in the thread describing
the
>additives to gasoline and how they do at stopping the smoke on an oil burner
like
>my 70 TR6...."
Neglectiing such causes as poor oil or old, broken-down oil, oil burning
could come from several sources, including valve guides, valve seals, and
piston rings. Worn guides must be replaced Worn valves must be replaced,
usually with guides as well. Slightly worn guides may be knurled, which is a
metal upsetting process which makes the fit around the valve stem tighter, is
cheaper than replacement, and sometimes preferred for lower friction, but
that's a very debatable point. Cracked, hardened, shrunken, or missing valve
seals must be replaced. Piston rings, however, may either be worn or gummed
up with carbon and varnish deposits. Worn rings will pass oil, and must be
replaced. The only hope for a non-surgical resolution to your problems lies
in gummed rings. If the rings and ring grooves are sufficiently caked with
combustion byproducts, varnish from gas & oil oxidation, and plain old
carbon, the rings may stick in the pistons, and not be free to spring out
into full contact with the cylinder walls. Oil additives can in some cases
loosen these deposits sufficiently to permit adequate ring movement and lower
your oil consumption. It's not a sure thing, and it really depends on the
nature and severity of deposits, but it can get better sometimes. I'd tend
to use both an upper cylinder lube (gas additive) and (more importantly) an
oil additive. It's worth a try...
By the way, Tony R. mentioned that Marvel Mystery Oil smells like automatic
transmission fluid. I don't know the compositioin of MMO, but in the
mid-70's Mazdas had pretty severe oil consumption problems and one standard,
factory-recommended procedure was to replace one or two quarts of engine oil
with ATF and run the car for a few weeks. The high solvency of the ATF
sometimes loosened the deposits enough to permit the side seals (like rings
in a piston engine) to move freely and function properly. It worked for me
on a couple of occasions... I've never tried it in a piston engine, both
because I usually tend to run for a wrench imediately and also because I
don't know how adversely the ATF affects boundary layer lubrication in
bearings, etc. Wankels have a different set of needs and may be more
tolerant of oil film strength breakdown. I just haven't found the righrt
place and time to experiment on a "real" engine...
Good luck!
-Karl
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