TM 5-3820-245-14&P
LUBRICATING OILS FOR DETROIT DIESEL ENGINES
reformulation. A close working relationship with the lube oil
DIESEL LUBRICATING.OILS
manufacturer should be maintained so that any reformulation
GENERAL CONSIDERATIONS
can be reviewed and decision made as to its affect on
continued satisfactory performance.
All diesel engines require heavy-duty lubricating oils Basic
requirements of such oils are lubricating quality, high heat
COLD WEATHER OPERATION
resistance, and control of contaminants
Two important considerations relate to satisfactory operation
under cold ambient temperature conditions These are (1 )'the
LUBRICATING QUALITY. The reduction of friction and wear
ability to crank the engine fast enough to secure starting, and
by maintaining an oil film between moving parts is the primary
(2) providing adequate lubrication to internal wearing surfaces
requisite of a lubricant. Film thickness and its ability to prevent
during starting and warm-up Once started and warmed up,
metal-to-metal contact of moving parts Is related to oil
external ambient temperatures have little effect on Internal
viscosity The optimums for Detroit Diesel engines are SAE 40
engine temperatures Both cold weather considerations can be
or 30 weight
adequately met through proper lube oil selection and the use
of auxiliary heat prior to starting Auxiliary heat can be used in
HIGH HEAT RESISTANCE.
Temperature is the most
the form of jacket water and oil pan heaters, hot air space
important factor in determining the rate at which deterioration
heaters applied to engine compartments, or some combination
or oxidation of the lubricating oil will occur The oil should have
of these.
adequate thermal stability at elevated temperatures, thereby
precluding formation of harmful carbonaceous and/or ash
Proper oil selection and oil heat can assure lubricant flow
deposits
immediately upon starting. Improper oil selection and oil heat
may result In starting with cold oil congealed in the oil pan, and
CONTROL OF CONTAMINANTS.
The piston and
little or no oil flow for lubricating internal parts once the engine
compression rings must ride on a film of oil to minimize wear
has started.
and prevent cylinder seizure At normal rates of consumption,
oil reaches a temperature zone at the upper part of the piston
Proper oil selection and jacket water heating can assure
where rapid oxidation and carbonlzation can occur In addition,
cranking capability by maintaining an oil film on cylinder walls
as oil circulates through the engine, It is continuously
and bearing surfaces in a condition which provides low friction,
contaminated by soot, acids, and water originating from
and hence, less cranking effort to achieve cranking speeds
Until they are exhausted, detergent and
necessary for reliable starting Improper oil selection and jacket
dispersant additives aid In keeping sludge and varnish from
water heating may result in congealed oil films on cylinder
depositing on engine parts. But such additives in excessive
walls and bearing surfaces, which result in high friction loads
quantities can result in detrimental ash deposits If abnormal
and more cranking effort than is available, thus preventing
amounts of insoluble deposits form, particularly on the piston
sufficient cranking speeds to assure reliable starting.
In the compression ring area, early engine failure may result
LUBE OIL SPECIFICATIONS
Oil that is carried up the cylinder liner wall is normally
consumed during engine operation The oil and additives leave
Detroit Diesel Alllson lubricant recommendations are based on
carbonaceous and/or ash deposits when subjected to the
general experience with current lubricants of various types and
elevated temperatures of the combustion chamber. The
give consideration to the commercial lubricants presently
amount of deposits is Influenced by the oil compositon,
available.
additive content, engine temperature, and oil consumption
rate.
RECOMMENDATION
Detroit Diesel 2-cycle engines have provided optimum
OIL QUALITY is the responsibility of the oil supplier. (The
performance and experienced the longest service life
term "old supplier" is applicable to refiners, blenders, and
operating with lubricating oils meeting the following ash limits,
rebranders of petroleum products, and does not include
zinc requirements, oil performance levels, viscosity grades,
distributors of such products) There are hundreds of
and evidence of satisfactory performance.
commercial crankcase oils marketed today Obviously, engine
manufacturers or users cannot completely evaluate the
Sulfated Ash Limit (ASTM D-874)
numerous commercial oils The selection of a suitable lubricant
The sulfated ash content of the lubricant shall not exceed
In consultation with a reliable oil supplier, observance of his oil
1.000% by weight, except lubricants that contain only barium
drain recommendations (based on used oil sample analysis
detergent-dispersant salts where 1.5% by weight is allowed
and experience), and proper filter maintenance will provide the
Lubricants having a sulfated ash content between 0 55% and
best assurance of 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 reformulate
content exceeding 0.85% by weight, are prone to produce
an old while maintaining the same API classification, or may
greater deposit levels in the piston ring grooves, exhaust valve
reformulate to a new API classification and continue the brand
faces and seats.
name designation. For example, SE oils being reformulated to
SF letter code classification may perform differently after this
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