Wärtsilä 32 Product Guide

Wärtsilä 32 - Product Guide
7. Lubricating Oil System
7. Lubricating Oil System
7.1 Lubricating oil requirements
7.1.1 Engine lubricating oil
The lubricating oil must be of viscosity class SAE 40 and have a viscosity index (VI) of minimum 95. The
lubricating oil alkalinity (BN) is tied to the fuel grade, as shown in the table below. BN is an abbreviation of
Base Number. The value indicates milligrams KOH per gram of oil.
Table 7.1 Fuel standards and lubricating oil requirements
Category
Fuel standard
Lubricating oil BN
A
ASTM D 975-01,
BS MA 100: 1996
CIMAC 2003
ISO8217: 1996(E)
GRADE NO. 1-D, 2-D
DMX, DMA
DX, DA
ISO-F-DMX, DMA
10...30
B
BS MA 100: 1996
CIMAC 2003
ISO 8217: 1996(E)
DMB
DB
ISO-F-DMB
15...30
C
ASTM D 975-01,
ASTM D 396-04,
BS MA 100: 1996
CIMAC 2003
ISO 8217: 1996(E)
GRADE NO. 4-D
GRADE NO. 5-6
DMC, RMA10-RMK55
DC, A30-K700
ISO-F-DMC, RMA10-RMK55
30...55
D
CRUDE OIL (CRO)
30...55
F
LIQUID BIO FUEL (LBF)
10...20
BN 50-55 lubricants are to be selected in the first place for operation on HFO. BN 40 lubricants can also
be used with HFO provided that the sulphur content of the fuel is relatively low, and the BN remains above
the condemning limit for acceptable oil change intervals. BN 30 lubricating oils should be used together
with HFO only in special cases; for example in SCR (Selective Catalyctic Reduction) installations, if better
total economy can be achieved despite shorter oil change intervals. Lower BN may have a positive influence
on the lifetime of the SCR catalyst.
Crude oils with low sulphur content may permit the use of BN 30 lubricating oils. It is however not unusual
that crude oils contain other acidic compounds, which requires a high BN oil although the sulphur content
of the fuel is low.
It is not harmful to the engine to use a higher BN than recommended for the fuel grade.
Different oil brands may not be blended, unless it is approved by the oil suppliers. Blending of different oils
must also be approved by Wärtsilä, if the engine still under warranty.
An updated list of approved lubricating oils is supplied for every installation.
7.1.2 Oil in speed governor or actuator
An oil of viscosity class SAE 30 or SAE 40 is acceptable in normal operating conditions. Usually the same
oil as in the engine can be used. At low ambient temperatures it may be necessary to use a multigrade oil
(e.g. SAE 5W-40) to ensure proper operation during start-up with cold oil.
7.1.3 Oil in turning device
It is recommended to use EP-gear oils, viscosity 400-500 cSt at 40°C = ISO VG 460.
An updated list of approved oils is supplied for every installation.
70 Product Guide W32 - 1/2013