For a
number of years we have been occasionally faced with an oil
economy problem in a propane or other gaseous fuel engine. There
have been many discussions directed at ring types: "you
can't use chrome", or "you can't use moly"; plain
compression rings are all that will work, etc. The popular theory
was that dry fuel does not have "fuel wash" as does
gasoline, so the rings will not "seat".
A
common field fix that has evolved from this is the use of
Bon Ami, an abrasive cleaning agent. It is either induced
through the carburetor or made into a slurry and spread on
the O.D. face of the piston ring. This is not a recommended practice of Hastings Manufacturing Company.
It is not recommended by any other internal engine parts manufacturer
we're aware of.
The introduction of any abrasive into
an engine ends up with the abrasive in the engine's lube oil
and creates uncontrollable, greatly accelerated wear on every
surface of the engine.
Hastings
Manufacturing Company conducted seven (7) dynamometer tests
to determine oil economy trends of gasoline versus gaseous fuels.
The parameters of the tests were:
1)
Cylinders deglazed with a flex-hone and thoroughly cleaned
between tests.
2) Good engine assembly procedures,
as outlined in "Service Tips for the Automotive Mechanic"
were utilized.
3) Tests 5, 6, and 7 used moly, chrome,
and plain compression rings, respectively. The test data shows
all ring types gave acceptable levels of oil economy.
The same levels of oil economy were
attained simply by following good, clean shop practices.
