TM 5-3895-359-14&P
LUBRICATING OILS FOR DETROIT DIESEL ENGINES
perform differently after this reformulation. A close working
DIESEL LUBRICATING OILS
relationship with the lube oil manufacturer should be
maintained so that any reformulation can be reviewed and
All diesel engines require heavy-duty lubricating oils. Basic
decision made as to its affect on continued satisfactory
requirements of such oils are lubricating quality, high heat
performance.
resistance, and control of contaminants.
COLD WEATHER OPERATION
LUBRICATING QUALITY. The reduction of friction and wear
Two important considerations relate to satisfactory operation
by maintaining an oil film between moving parts is the primary
under cold ambient temperature conditions. These are: (1)
requisite of a lubricant. Film thickness and its ability to
the ability to crank the engine fast enough to secure starting,
prevent metal-to-metal contact of moving parts is related to oil
and (2) providing adequate lubrication to internal wearing
viscosity. The optimums for Detroit Diesel engines are SAE
surfaces during starting and warm-up. Once started and
40 or 30 weight.
warmed up, external ambient temperatures have little effect
on internal engine temperatures.
Both cold weather
HIGH HEAT RESISTANCE.
Temperature is the most
considerations can be adequately met through proper lube oil
important factor in determining the rate at which deterioration
selection and the use of auxiliary heat prior to starting.
or oxidation of the lubricating oil will occur. The oil should
Auxiliary heat can be used in the form of jacket water and oil
have adequate thermal stability at elevated temperatures,
pan heaters, hot air space heaters applied to engine
thereby precluding formation of harmful carbonaceous and/or
compartments, or some combination of these.
ash deposits.
Proper oil selection and oil heat can assure lubricant flow
The piston and
CONTROL OF CONTAMINANTS.
immediately upon starting. Improper oil selection and oil heat
compression rings must ride on a film of oil to minimize wear
may result in starting with cold oil congealed in the oil pan,
and prevent cylinder seizure. At normal rates of consumption,
and little or no oil flow for lubricating internal parts once the
oil reaches a temperature zone at the upper part of the piston
engine has started.
where rapid oxidation and carbonization can occur. In
addition, as oil circulates through the engine, it is continuously
Proper oil selection and jacket water heating can assure
contaminated by soot, acids, and water originating from
cranking capability by maintaining an oil film on cylinder walls
Until they are exhausted, detergent and
and bearing surfaces in a condition which provides low
dispersant additives aid in keeping sludge and varnish from
friction, and hence, less cranking effort to achieve cranking
depositing on engine parts. But such additives in excessive
speeds necessary for reliable starting. Improper oil selection
quantities can result in detrimental ash deposits. If abnormal
and jacket water heating may result in congealed oil films on
amounts of insoluble deposits form, particularly on the piston
cylinder walls and bearing surfaces, which result in high
in the compression ring area, early engine failure may result.
friction loads and more cranking effort than is available, thus
preventing sufficient cranking speeds to assure reliable
Oil that is carried up the cylinder liner wall is normally
starting.
consumed during engine operation. The oil and additives
leave carbonaceous and/or ash deposits when subjected to
LUBE OIL SPECIFICATIONS
the elevated temperatures of the combustion chamber. The
Detroit Diesel Allison lubricant recommendations are based
amount of deposits is influenced by the oil composition,
on general experience with current lubricants of various types
additive content, engine temperature, and oil consumption
and give consideration to the commercial lubricants presently
rate.
available.
OIL QUALITY is the responsibility of the oil supplier. (The
RECOMMENDATION
term "oil supplier" is applicable to refiners, blenders, and
Detroit Diesel 2-cycle engines have provided optimum
rebranders of petroleum products, and does not include
performance and experienced the longest service life
distributors of such products).
operating with lubricating oils meeting the following ash limits,
zinc requirements, oil performance levels, viscosity grades,
There are hundreds of commercial crankcase oils marketed
and evidence of satisfactory performance.
today. Obviously, engine manufacturers or users cannot
completely evaluate the numerous commercial oils. The
Sulfated Ash Limit (ASTM D-874)
selection of a suitable lubricant in consultation with a reliable
The sulfated ash content of the lubricant shall not exceed
oil supplier, observance of his oil drain recommendations
1.000% by weight, except lubricants that contain only barium
(based on used oil sample analysis and experience), and
detergent-dispersant salts where 1.5% by weight is allowed.
proper filter maintenance will provide the best assurance of
Lubricants having a sulfated ash content between 0.55% and
satisfactory oil performance.
0.85% by weight, have a history of excellent performance in
Detroit Diesel engines. Lubricants having a sulfated ash
It should be noted that lube oil manufacturers may
content exceeding 0.85% by weight, are prone to produce
reformulate an oil while maintaining the same API
greater deposit levels in the piston ring grooves, exhaust valve
classification, or may reformulate to a new API classification
faces and seats.
and continue the brand name designation. For example, SE
oils being reformulated to SF letter code classification may
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