Kohler SFGLD480 Operation & Maintenance Manual page 244

An increase in the content of any metal indicates wear or damage of an engine component. The metal present in
oil can identify the engine part concerned. For example:
An increase in the content of lead and copper should lead to an inspection of the bearings, bushings...
-
- An increase in the iron content should bring about an inspection both of the cylinder liners and of the timing
gears.
A higher content of aluminium may be caused by an incipient peeling of the piston material.
-
- The presence of silicon is, generally, due to poor filtering of inlet air; however, in biogas applications, this
element originates in the gas fuel itself.
For all those reasons, in determining the oil service life, it will be necessary to implement an analysis program that
provides information on the oil performance tendency or specific details on its evolution.
Initially and until the oil change frequency has been fixed, it is advisable to take oil samples for subsequent
analysis by a specialist laboratory every 100h. Depending on the test results, sampling intervals may then
change. Based on our knowledge and experience, for natural gas fuelled engines, we would recommend
sampling oil at least at the oil's half-life and at oil change.
The high limits of acceptability of an oil for natural gas, biogas or biomass gas engines have been established
from a database obtained through the use of the lubricant in real operating conditions and tests of waste oil.
These are the properties to be analyzed and their high limits of acceptability:
Property
Viscosity
TBN
TAN
pH
Oxidation
Nitration
Water content
Insoluble substances
Metals
Silicon
Chlorine
* Reaching this limit before the time interval specified in the oil servicing Instruction Sheet will probably be due to
a poor quality of the gas.
The frequency of analysis and the test results determine the oil changing requirements in each individual case.
When altering the oil change intervals, bear in mind not only the test results, but also the engine condition and
operating temperature. If oil and water temperatures are kept within the manufacturer-specified range, in
particular during lengthy periods of operation at low load, the probability of corrosive vapor condensation will be
minimized. This, in turn, will reduce the TBN depletion rate and consequently increase the time oil can be used.
PRODUCT INFORMATION
IO-G-M-25-001e
GAS-FUELED ENGINE OIL SERVICING INSTRUCTIONS
Oil from natural gas engines
+ - 25%
-50% fresh oil
+2 mgKOH/g fresh oil
4,5
20 Abs/cm
20 Abs/cm
Max. 0.5%
Max. 1.0%
Fe<100 ppm
Cu<40 ppm
Cr<25 ppm
Sn< 25ppm
Al<20ppm
Pb<40ppm
Na<40ppm
Si< 30 ppm
INDEX
G
Oil from landfill or digester gas engines
+ - 25%
-50% fresh oil
+2 mgKOH/g fresh oil
4,5
20 Abs/cm
20 Abs/cm
Max. 0.5%
Max. 1.0%
Fe<100 ppm
Cu<40 ppm
Cr<25 ppm
Sn< 25ppm
Al<20ppm
Pb<40ppm
Na<40ppm
Si<75, provided it comes from the gas *.
< 800 ppm
5.2.4
DATE
Dep.2
January 2015
O&M_2.002211.810_A_10_2016
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