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3.3 General Recommendations
Service experience has shown that the corrosion behavior can vary significantly while
the engine operates at less than 60% CMCR (low load).
If the engine is to be operated at continuous low load (i.e. more than 24 hours of
operation below 60% CMCR) and the sulphur content of the used HFO is more than
2.5% m/m, WinGD strongly recommends the use of a BN 100 cylinder lubricating oil,
as the cylinder oil feed rate cannot be adjusted to adequately compensate for the
lower alkalinity. If you use a cylinder lubricating oil with a BN less than 100, the
permitted maximum feed rate is 1.2 g/kWh (see 7218−1 Cylinder Lubrication and
7218−3 Feed Rate − Adjustment). If the analysis of the piston underside drain oil
shows that an adjustment to a higher feed rate than 1.2 g/kWh is necessary, you must
change to a BN 100 cylinder lubricating oil.
For data about validated cylinder lubricating oils, see paragraph 8.2.
Note: You can use the WinGD Blending on Board package to adjust the base
number of the cylinder lubricating oil. For more data, speak to or send a
message to WinGD.
It is necessary to monitor the residual BN at regular intervals (see paragraph 3.1 and
paragraph 3.2). WinGD recommends the use of an on-board monitoring programme
that, at a minimum, gives you an analysis of the residual BN from the piston
underside drain oil. WinGD also recommends the analysis of the total iron and
chromium content in the piston underside oil. A sudden increase of the iron or
chromium content indicates excessive cold corrosion (see paragraph 3.2).
3.4 Intermediate BN Lubricating Oils
If an intermediate BN cylinder lubricating oil (BN is more than 50 mg KOH/g and less
than 60 mg KOH/g) is used, WinGD recommends the procedures that follow:
D Use an on-board monitoring programme that, at a minimum, gives you an
analysis of the residual BN from the piston underside drain oil. The
recommended intervals for an analysis are:
a) At each bunker change of the HFO (very important if the sulphur content of the
HFO is more than 2.5% m/m).
b) At each change of more than 10% CMCR of the average engine (24 hours).
c) A minimum of one time each week.
CAUTION
For engine operation at less than 60% CMCR (low load) for more
than 24 hours, you must only use intermediate BN lubricating oils
(between BN 50 and BN 60) if the sulphur content of the used HFO
is in the range of 0.5% m/m to 2.5% m/m.
2017−08
Lubricating Oils
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