N40469 Chapter 4 Engine fluids Fuel specification To get the correct power and performance from your engine, use good quality fuel. The recommended fuel specification 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 flow 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. 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 flow through the filter. 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. Page 19 Percentage of sulphur in the fuel (%) Oil change interval Normal 0.5 to 1.0 0,75 of normal > 1.0 0,50 of normal