SEBU8191-01 29
Maintenance Section
Refill Capacities
In addition to t
he new tests, API CH-4 oils have
tougher limits for viscosity control in applications that
generate high soot. The oils also have improved
oxidation res
istance. API CH-4 oils must pass an
additional test (piston deposit) for engines that use
aluminum pistons (single piece). Oil performance is
also establi
shed for engines that operate in areas
with high sulfur diesel fuel.
All of these
improvements allow the API CH-4
oil to achieve optimum oil change intervals. API
CH-4 oils are recommended for use in extended oil
change inte
rvals. API CH-4 oils are recommended
for conditions that demand a premium oil. Your
Perkins dealer or your Perkins distributor has specific
guideline
s for optimizing oil change intervals.
Some commercial oils that meet the API
classifica
tions may require reduced oil change
intervals. To determine the oil change interval, closely
monitor the condition of the oil and perform a wear
metal ana
lysis.
NOTICE
Failure to follow these oil recommendations can cause
shorten
ed engine service life due to deposits and/or
excessive w ear.
Total Base Number (TBN) and Fuel Sulfur
Levels
for Direct Injection (DI) Diesel
Engines
The To
tal Base Number (TBN) for an oil depends on
the fuel sulfur level. For direct injection engines that
use distillate fuel, the minimum TBN of the new oil
must b
e ten times the fuel sulfur level. The TBN is
defined by “ASTM D2896”. The minimum TBN of the
oil is 5 regardless of fuel sulfur level. Illustration 25
demo
nstrates the TBN.
g00799818
Illustration 25
(Y) TBN by “ ASTM D2896”
(X) Percentage of fuel sulfur by weight
(1) TBN of new oil
(2) Change the oil when the TBN deteriorates to 50 percent of
the original TBN.
Use the followi
ng guidelines for fuel sulfur levels that
exceed 1.5 percent:
•
Choose an oil w
ith the highest TBN that meets one
of these classifications: EMA DHD-1 and API CH-4.
•
Reduce the oi
l change interval. Base the oil
change interval on the oil analysis. Ensure that the
oil analysis includes the conditio n of the oil and a
wear metal a
nalysis.
Excessive piston deposits can be produced by an oil
withahighT
BN. These deposits can lead to a loss
of control of the oil consumption and to the polishing
of the cylinder bore.
NOTICE
Operating Direct Injection (DI) diesel engines with fuel
sulphur levels over 0.5 percent will require shortened
oil chang
e intervals in order to help maintain adequate
wear protection.
Table 9
Percentage of Sulfur in
the fuel
Oil change interval
Lower than 0.5 Normal
0.5to1.0
0.75 of
normal
Greater than 1.0 0.50 of normal
Lubricant Viscosity Recommendations
for D irect Injection (DI) Diesel Engines
The correct SAE viscosity grade of oil is determined
by the minimum ambient temperature during
cold engine start-up, and the maximum ambient
temperature during engine operation.
Refer to Table 10 (minimum temperature) in order
to determine the required oil viscosity for starting a
cold engine.
Refer to Table 10 (maximum temperature) in order
to select the oil viscosity for engine operation at the
highest ambient temperature that is anticipated.
Generally, use the highest oil viscosity that is
available to meet the requirement for the temperature
at start-up.
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