3Com Caterpillar Commercial Diesel Engine SEBU6251-06 - Manual (Page 18)

18
Maintenance Section
Fuel Specifications
Fuel Heaters
The fuel cloud point is related to problems with
fuel filters. The heater heats the fuel above the
cloud point before the fuel enters the fuel filter. This
prevents wax from blocking the filter. Fuel can flow
through pumps and lines at temperatures below the
cloud point. The cloud point is often above the pour
point of a fuel. While the fuel can flow through these
lines, the wax in the fuel can still plug the fuel filter.
In some engine installations, small modifications
can prevent problems that are caused by the cloud
point. One of the following changes can prevent
problems in many conditions: a change in the
location of fuel filters and/or supply lines and the
addition of insulation. In extreme temperatures,
heating of the fuel may be required to prevent the
filters from plugging. There are several types of fuel
heaters that are available. The heaters use either
engine coolant or exhaust gas as a heat source.
These systems may prevent filter waxing problems
without the use of de-icers. These systems may be
ineffective when the fuel contains a large amount
of dirt or of water. Use of a fuel heater can help
eliminate some cold weather problems. A fuel
heater should be installed so that the fuel is heated
before flowing into the fuel filter.
Note: Only use fuel heaters that are controlled
by thermostats or use fuel heaters that are
self-regulated. Do not use fuel heaters in warm
temperatures.
Select a fuel heater that is mechanically simple, yet
adequate for the application. The fuel heater should
also prevent overheating of the fuel. Disconnect the
fuel heater or deactivate the fuel heater in warm
weather. An unacceptable loss of fuel viscosity
and engine power will occur if the fuel supply
temperature is allowed to become too hot.
For additional information on fuel heaters, see your
Caterpillar dealer.
De-Icers
De-icers lower the freezing point of the moisture in
the fuel. De-icers are not generally needed when
fuel heaters are used. If you experience trouble,
consult your fuel supplier for recommendations of
a compatible commercial de-icer.
i01111474
Fuel Recommendations
SMCS Code: 1250; 1280
Diesel engines have the ability to burn a wide
variety of fuels. These fuels are divided into two
general groups. The two groups are called the
preferred fuels and the permissible fuels.
The preferred fuels provide maximum engine
service life and performance. The preferred fuels
are distillate fuels. These fuels are commonly called
diesel fuel, furnace fuel, gas oil, or kerosene.
The permissible fuels are crude oils or blended
fuels. Use of these fuels can result in higher
maintenance costs and in reduced engine service
life.
Diesel fuels that meet the specifications in Table 7
will help to provide maximum engine service life
and performance. In North America, diesel fuel that
is identified as No. 1-D or No. 2-D in “ASTM D975”
generally meet the specifications. Table 7 is for
diesel fuels that are distilled from crude oil. Diesel
fuels from other sources could exhibit detrimental
properties that are not defined or controlled by this
specification.
Table 7
Caterpillar Specifications for Distillate Diesel Fuel
Specifications Requirements ASTM
Test
Aromatics 35% maximum “D1319”
Ash 0.02% maximum (weight) “D482”
Carbon Residue
on 10% Bottoms 0.35% maximum (weight) “D524”
40 minimum (DI engines)
Cetane Number
35 minimum (PC engines)
“D613”
Cloud Point
The cloud point must
not exceed the lowest
expected ambient
temperature. -
Copper Strip
Corrosion No. 3 maximum “D130”
10% at 282

C (540

F)
maximum
Distillation
90% at 360

C (680

F)
maximum
“D86”
Flash Point legal limit “D93”
(continued)