TRUCK SERVICE MANUAL
ENGINE
Table 2-18: Thermal Control Settings
Setting With
Setting With
Setting With
160 deg. to 175 deg. F
170 deg. to 185 deg. F
180 deg. to 195 deg. F
Control
[71 deg. to 79 deg. C]
[77 deg. to 85 deg. C]
[82 deg. to 91 deg. C
Used
Thermostat
Thermostat
Thermostat
Open
Close
Open
Close
Open
Close
Thermatic Fan
185 deg. F
170 deg. F
190 deg. F
182 deg. F
Not Used
[85 deg. C]
[77 deg. C]
[88 deg. C]
[83 deg. C]
Shutterstat
180 deg. F
172 deg. F
185 deg. F
177 deg. F
195 deg. F
187 deg. F
[82 deg. C]
[78 deg. C]
[85 deg. C]
[81 deg. C]
[91 deg. C]
[86 deg. C]
Modulating
175 deg. F
185 deg. F
195 deg. F
Shutters Open
[79 deg. C]
[85 deg. C]
[91 deg C]
Check Crankshaft End Clearance (At Clutch
Adjustment)
Table 2-19: Crankshaft End Clearance - Inch [mm]
The crankshaft of a new or newly rebuilt engine must
have end clearance as listed In Table 2-19. A worn
Engine
New
New
Worn
engine must not be operated with more than the worn
Series
Minimum
Maximum
Limit
limit and clearance shown in the same table. If engine is
NH, NT
0.007
0.017
0.022
disassembled for repair, install new thrust rings.
[0.18]
[0.43]
[0.56]
The check can be made by attaching an indicator to rest
against the damper or pulley, Fig. 2-71, while prying
against the front cover and inner part of pulley or
damper. End clearance must be present with engine
mounted in the unit and assembled to transmission or
converter.
Caution: Do not pry against outer damper ring.
Viscosity Recommendations
Lubricant
1. Multigraded lubricating oils may be used in
applications with wide variations in ambient temperatures
Lubricating Oil
if they meet the appropriate performance specifications
and ash content limits shown in Table 3-1. Multigraded
Lubricating oil is used in Cummins engines to lubricate
oils are generally produced by adding viscosity index
moving parts, provide internal cooring and keep the
improver additives to a low viscosity base stock to retard
engine clean by suspending contaminants until removed
thinning effects at operating temperatures. Poor quality
by the oil filters.
Lubricating oil also acts as a
multigraded oils use a viscosity index improver additive
combustion seal and protects internal parts from rust and
which has a tendency to lose its effectiveness after a
corrosion.
short period of use in a high speed engine. These oils
should be avoided.
The use of quality lubricating oil, combined with
2. Oils which meet the low temperature SAE viscosity
appropriate lubricating oil, drain and filter change
standard (0 deg F [- 18 deg C] carry a suffix "W". Oils
intervals, is an important factor in extending engine life.
that meet the high temperature viscosity SAE standard
Cummins Engine Company, Inc. does not recommend
210 deg F [99 deg C)) as well as the low temperature
any specific brand of lubricating oil, The responsibility for
carry both viscosity ratings - example 20-20W. See
meeting the specifications, quality and performance of
Table 3-2.
lubricating oils must necessarily rest with the oil supplier.
Table 3-2: Operating Temperatures Vs Viscosity
Break In Oils
Ambient Temperatures
Viscosity
Special "Break-In" lubricating oils are not recommended
for new or rebuilt Cummins Engines. Use the same
-10 deg. F [-23 deg. C] and below
See Table 3-3.
-10 to 30 deg. F [-23 to -1 deg. C]
10W
lubricating oil as will be used for the normal engine
20 to 60 deg. F [-7 to 16 deg. C]
20 - 20W
operation.
40 deg. F [4 deg. C] and above
30
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