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Perkins L4 Diesel engines are vertical four-stroke
Power Units. They are entirely of British design
and manufacture and embody the results of
experience gained in the production of Diesel
engines over a period of many years.
Crankshaft and Main Bearings.
The crankshaft is made from an alloy steel
stam ping, with hardened main and crankpin
journais. The crankshaft runs in three pre-finished
replaceable shell hearings, which are lead bron ze
lined and indium flashed.
The materials and workmanship throughout are
of the highest class. Most parts are guaranteed
interchangeable, jigs being used everywhere in the
course of manufacture, and all parts pass through
a system of thorough inspection where they are
checked to the closest limits. Each engine is
subjected to stringent tests before leaving the
Works.
Connecting Rods.
The connecting rods are of alloy steel ., H "
section stampings with replaceable steel shell big
end bearings, which are lead bronze lined and
indium flashed.
Pistons.
The pistons are flat topped.
They are of light
aluminium alloy with ample metal in the crown to
carry off the heat of combustion.
Three com.
pression rings of which ODe is of laminated steel,
and ODe scraper ring are fitted above the gudgeon
pin.
There is ODe scraper ring below that pin.
The gudgeon pins are of the fully floating type.
General.
The Perkins lA Diesel, with which tbis man ua I
is concerned, is a Cour cylinder unit. having a
bore and stroke of 4* in. (107.95 mm) and 4i In.
(120.65 mm) respectively.
Cylinder Block.
The cylinder block and crankcase comprise a
one-piece high duty alloy iron casting.
Centri-
fugal cast iron wet liners are fitted, which are
flanged at the top end and fitted with sealing rings
at the lower end.
Timing Drive.
The camshaft and fuel pump are gear driven,
the timing case being a separate casting secured
to the front end of the cylinder block.
Provision
is made for mounting a gear drive on the timing
case meshing with the timing gear train, for driving
a hydraulic pump or uther low power auxiliary.
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Cylinder Head.
The cylinder head is an alloy iron casting,
secured to the cylinder block by a large number
of weU spaced through studs. The overhead
valves are operated by push rods from flat faced
tappets in the cylinder block, the rocker assembly
being mounted on top of the cylinder head. The
whole assembly is enclosed in a light alloy die cast
cover. All valves are of special alloy steel, the
inlet being larger to ensure maximum volumetric
efficiency. The spherical combustion chamber is
formed half in the head and half by a detachable
steel cap.
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Lubrication.
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Lubrication is high pressure force reed thrOUgh-
out the engine. The pump, a gear type, is secured
to the cylinder block and is driven by spiral gears
from the camshaft. It is fully capable of main-
taining an adequate pressure at all running speeds.
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FoeI Injection Equipment.
The unit type fuel pump is fiange mounted
on the timing case.
The atomisers are two hole type fitted in an
accessible position on top of the cylinder head ;
ODe spray is directed into the combustion chamber
and the other into the cylinder, ensuring easy
starting.
Camshaft.
The low level camshaft is situated in the offside
of the cylinder block and is supported by three
hearings.
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