
Workshop Manual, TPD 1350, issue 3
63
13
New 1000 Series
Piston and connecting rod
assemblies
13
General description
The pistons used in the New 1000 Series engines
have a "Fastram" combustion chamber in the top of
the piston (A). The piston (B) for engine types AR and
AS has two recesses in the top face for the valves.
The combustion chamber is designed to give an
efficient mix of fuel and air.
The pistons and connecting rods are matched to the
relevant cylinder.
The pistons have two compression rings and an oil
control ring. The groove for the top ring has a hard
metal insert to reduce wear of the groove. The piston
skirt has a layer of graphite to improve the wear
characteristics.
Axial location of the fully floating gudgeon pin is by
circlips. The gudgeon pin is off-centre to reduce the
noise level.
Piston cooling jets are fitted in the cylinder block to
spray lubricating oil onto the inner surface of the
pistons.
Note: Engine types AR and AS have only one cooling
jet fitted to spray the number one piston.
The correct piston height is important to ensure that
the piston does not contact the cylinder head and to
ensure the efficient combustion of fuel.
The piston height is controlled by the length of the
connecting rod. In the factory there are six length
grades of connecting rods and one piston are used to
obtain the correct piston height.
To obtain the different grades, the small-end bush is
machined off-centre. The amount that the bush is off-
centre gives the different length grades.
In service, a partially finished small-end bush is
available, which can be fitted to the original
connecting rod and machined to obtain the correct
length grade
, see operation 13-10
. Specialist
equipment and personnel with the correct training are
needed to machine the partially finished small-end
bush. Connecting rod kits are also available with the
small end bush fitted and machined to obtain the
correct connecting rod grade. For further information
refer to your nearest Perkins distributor.
Continued
A
A0071
B
A0071
Purchased from www.WorkshopManuals.co.uk
Содержание New 1000 Series
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