way the troughs work in the ZC-52 is to limit the amount of oil
available to be splashed after starting and while the engine is
running. This is done by making the top of the trough higher than
the oil level in the crankcase. A hole allows a small amount of
oil to flow into the trough, the idea being that the rod will splash
out almost all of the oil soon after start. Then, the oil level
is only allowed to rise to where the rod can splash it. This
limited amount of oil is supposed to limit smoking and excess oil
Because the amount of oil splashed around is
limited, Fairbanks-Morse made up a trough to catch oil and funnel it to
the mains. Here is what I've done.
Main bearing collecting troughs.As you can see, the oil is collected and channeled into the main bearing oil holes.
With oil in crankcase.
I was concerned about oil starvation, I raised the oil level to about
1/4" higher than it originally was. This had the "resting" oil
level just slightly above the tops of the dippers (the rods themselves
just barely touched the oil). In an hour of running the engine,
smoking was, I think, slightly decreased.
I then drained
off oil until it was at the original "full" mark on the dip stick and
ran it for about an hour longer. Smoking was slightly decreased
from the last test.
I drained an additional couple of ounces of
oil, bring the level down to about the "low" mark on the dip stick,
which still had the rods dipping about 1/4". When I discontinued
the test run after about another half hour, it was smoking less.
I will have to run the engine for a few more hours to see if it
dries out as the rings re-seat after removing the pistons yesterday.
engine might just be a smoky design. If I cut back the oil much
more, I'm afraid the mains will be starved. At least, it doesn't
appear to be fouling the plugs.