User Manual

N40469 Chapter 4
Page 19
Engine uids
Fuel specication
To get the correct power and performance from your
engine, use good quality fuel. The recommended fuel
specication for Perkins engines is indicated below:
Cetane number .........................................45 minimum
Viscosity ...........................2.0/4.5 centistokes at 40
O
C
Density.......................................... 0,835/0,855 kg/litre
Sulphur .................................0.2% of mass, maximum
Distillation ..............................................85% at 350
O
C
Cetane number indicates ignition performance. A
fuel with a low cetane number can cause cold start
problems and affect combustion.
Viscosity is the resistance to ow and engine
performance can be affected if it is outside the limits.
Density: A lower density reduces engine power, a
higher density increases engine power and exhaust
smoke.
Sulphur: A high amount of sulphur (not normally
found in Europe, North America or Australasia) can
cause engine wear. Where only high sulphur fuels
are available, it is necessary to use a highly alkaline
lubricating oil in the engine or to renew the lubricating
oil more frequently, see the table below.
Percentage of sulphur
in the fuel (%)
Oil change interval
<0.5 Normal
0.5 to 1.0 0,75 of normal
> 1.0 0,50 of normal
Distillation: This is an indication of the mixture of
different hydrocarbons in the fuel. A high ratio of
light-weight hydrocarbons can affect the combustion
characteristics.
Low temperature fuels
Special winter fuels may be available for engine
operation at temperatures below 0
O
C. These fuels have
a lower viscosity and also limit the wax formation in the
fuel at low temperatures. If wax formation occurs, this
could stop the fuel ow through the lter.
If you need advice on adjustments to an engine setting
or to the lubricating oil change periods which may be
necessary because of the standard of the available
fuel, consult your nearest Perkins distributor.