compression ratio LAND ROVER DISCOVERY 2002 User Guide

ENGINE MANAGEMENT SYSTEM - TD5
18-1-32 DESCRIPTION AND OPERATION
Turbocharger
1Exhaust gas from manifold
2Studs to exhaust manifold
3Turbocharger cast iron housing
4Wastegate valve linkage
5Exhaust gas out to front exhaust pipe
6Compressed intake air
7Fresh intake air
8Turbocharger aluminium alloy housing
9Wastegate valve vacuum port
The Td5 engine utilises a Garrett GT20 turbocharger with an electronically controlled wastegate modulator to improve
engine performance. The turbocharger uses the engine's exhaust gas to spin a turbine at very high speed. This
causes inlet air on the other side of the turbine to be drawn in through the turbocharger intake for compression. The
inlet air is carried round by the vanes of the compressor and then thrown out under centrifugal force from the
turbocharger's outlet duct. This compression of air enables a greater quantity of air to be delivered to the inlet manifold
via an intercooler. Combustion is improved through better volumetric efficiency. The use of a turbocharger improves
fuel consumption and increases engine torque and power. Exhaust noise is also reduced due to the smoothing out of
exhaust pulsations.
The rear cast iron body of the turbocharger housing connects to a port on the exhaust manifold at the LH side of the
cylinder head by three studs and nuts. The interface between the exhaust manifold and the turbocharger housing is
separated by a metal gasket. The exhaust outlet of the turbocharger is located at the bottom of the turbocharger cast
iron housing; it is connected to the exhaust system front downpipe and is attached by three studs and nuts. The
interface between the turbocharger housing and the exhaust front pipe is separated by a metal gasket.
The front casing of the turbocharger is constructed from aluminium alloy and is connected to the air inlet duct by a
metal band clip. The compressed air outlet is connected to the intercooler by a metal pipe which has rubber hose
extensions at each end attached by metal band clips.

FUEL DELIVERY SYSTEM - TD5
19-1-8 DESCRIPTION AND OPERATION
The five injectors are located in the cylinder head, adjacent to the camshaft, with the nozzle of each injector protruding
directly into the cylinder. Each injector is sealed into the cylinder head with an 'O' ring and a copper washer and
secured with a clamp and bolt.
Each injector is operated mechanically by an overhead camshaft and rocker and electrically by a solenoid controlled
by the ECM. Each injector is supplied with pressurised fuel from the pump via the regulator housing and internal
drillings in the cylinder head.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.
The solenoid housing is secured to the injector body with two cap screws and is a sealed unit with a two pin electrical
connector on its top face.
The injector body is machined from a forging. The body has a machined central bore which locates the push rod. A
thread on the outer diameter provides the attachment for the nozzle cap nut. The body also provides attachment for
the solenoid housing.
The injector push rod is operated from the rocker and cam assembly by a socket. The push rod is located in the
housing bore and retained in its extended position by a push rod return spring. The powerful spring ensures that the
push rod socket is always in contact with the rocking lever and the cam.
The lower part of the injector housing locates the spring loaded nozzle. The nozzle is retained in the housing by a
nozzle cap nut which is screwed onto the housing. The nozzle cap nut has four holes around its circumference which
connect to the fuel return drilling in the cylinder head. The injector housing has ports located above the nozzle cap
nut which connect with the fuel delivery drilling in the cylinder head. An 'O' ring seals the injector in the machined
location in the cylinder head and a copper washer seals the injector from the combustion chamber.
The injectors are supplied with pressurised fuel from the fuel pump, via the pressure regulator housing and internal
drillings in the cylinder head. Each injector sprays fuel directly into the cylinder at approximately, 1500 bar (22000
lbf.in
2) on pre EU3 models and 1750 bar (25500 lbf.in2) on EU3 models, atomising the fuel and mixing it with intake
air prior to combustion.
The camshaft and rocker arrangement depresses the push rod which pressurises the fuel within the injector. When
the injector is required to inject fuel into the cylinder, the ECM energises the solenoid which closes a valve within the
solenoid housing. The closure of the valve stops the fuel entering the return line to the pump, trapping it in the injector.
The compression of the fuel by the push rod causes rapid pressurisation of the fuel which lifts the injector nozzle,
forcing the fuel into the cylinder at high pressure. The ECM controls the injection timing by altering the time at which
the solenoid is energised and the injection period by controlling the period for which the solenoid is energised.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

CLUTCH - TD5
33-1-8 DESCRIPTION AND OPERATION
The dual mass flywheel is used to insulate the gearbox from torsional and transient vibrations produced by the engine.
The flywheel comprises primary and secondary flywheels with the drive between the two transferred by a torsional
damper which comprises four coil springs. The springs are located in the inside diameter of the primary flywheel. Two
of the springs are of smaller diameter and fit inside the larger diameter springs.
The primary flywheel locates the ring gear and is attached to the crankshaft flange with eight bolts. The two pairs of
coil springs are located in a recess in the flywheel between two riveted retainers. A roller bearing is pressed onto the
central boss of the primary flywheel and retained with a riveted plate. The bearing provides the mounting for the
secondary flywheel.
The secondary flywheel comprises two parts; an outer flywheel which provides the friction surface for the clutch drive
plate and an inner drive plate which transfers the drive from the primary flywheel, via the coil springs, to the outer
flywheel. The two components of the secondary flywheel are secured to each other with rivets. The inner drive plate
is located between the two pairs of coil springs and can rotate on the ball bearing in either direction against the
combined compression force of the four coil springs. Under high torque loading conditions the secondary flywheel can
rotate in either direction up to 70
° in relation to the primary flywheel.
The operating face of the secondary flywheel is machined to provide a smooth surface for the drive plate to engage
on. Three dowels and six studs and nuts provide for the location and attachment of the pressure plate.
Pressure plate
1Leaf spring
2Drive plate
3Pressure plate
4Cover
5Diaphragm
6Rivet

CLUTCH - V8
DESCRIPTION AND OPERATION 33-2-9
The drive plate is of the spring centred type and is sandwiched between the pressure plate and the flywheel. The drive
plate has a splined hub which engages with the splines on the primary drive shaft from the gearbox. The hub is located
in an inner plate which contains six compression damper springs. A spring retainer plate and a disc adaptor are
secured together with stop pins which limit the angular deflection of the disc adaptor. Engine power is transmitted from
the disc adaptor to the damper springs. The damper springs then transfer the power to the retainer plate and the hub.
Friction washers are located between the hub, retainer plate and disc adaptor and provide further damping.
A spring steel plate is riveted to the disc adaptor and provides the attachment surface for the drive plate friction
material. The friction material comprises discs which are secured with rivets to each side of the plate. The rivets are
installed through recessed holes in the disc and emerge in recessed holes in the opposite disc. The drive plate is 267
mm (10.5 in) diameter and has a friction material manufactured from APTEC T385.

FRONT SUSPENSION
60-4 DESCRIPTION AND OPERATION
Description
General
The front suspension comprises two dampers and coil springs, two radius arms, a Panhard rod and an anti-roll bar.
The front axle provides the location points for the dampers, springs, radius arms and the Panhard rod.
The anti-roll bar assembly is an essential part of the front suspension. On vehicles without Active Cornering
Enhancement (ACE) a conventional 'passive' anti-roll bar is fitted. On vehicles fitted with the ACE system, a thicker
diameter anti-roll bar, known as a torsion bar, is used with an actuator at one end.

+ FRONT SUSPENSION, DESCRIPTION AND OPERATION, Description - ACE.
The hydraulic dampers and coil springs provide springing for each front wheel. The long travel dampers, springs and
radius arms provide maximum axle articulation and wheel travel for off-road driving. The front axle is controlled
longitudinally by two forged steel radius arms and transversely by a Panhard rod.
Radius arms
Each radius arm is manufactured from forged steel. Two bushes are pressed into the forward end of the radius arm.
The forward end of the radius arm is located in a fabricated bracket on the axle and secured through the bushes with
two bolts and nuts. A bush is pressed into the rear of the radius arm which is also located in a fabricated bracket on
each chassis longitudinal and secured through the bush with a bolt and nut.
The radius arms prevent longitudinal movement of the front axle and because of their length allow maximum axle
articulation. The stiffness of the bushes in each radius arm also contributes to the vehicle roll stiffness.
Each radius arm has a notch on its lower edge which provides location for the vehicle jack.
Dampers
Two conventional telescopic dampers are used to control body/axle movement. A turret is located on a bracket welded
to the chassis. The upper spring seat has four studs which pass through holes in the bracket and align with
corresponding holes in the turret. Four nuts are screwed onto the studs and secure the turret and upper spring seat
to the chassis.
A fabricated platform is welded to the axle. The platform has two captive nuts which provide for the attachment of the
damper. A lower spring seat is located on the platform. Each spring seat is handed and has a bracket which secures
the ABS sensor harness and the front brake hose.
Each damper is fitted with a bush at its upper end. The bush locates in the top of the turret and is secured with a cross
bolt. The lower attachment point for the damper is also fitted with a bush. This bush has a spindle through its centre
with a hole at each end. The spindle is seated on the lower spring seat and the axle platform and secured with two
bolts. The coil spring is fitted in a compressed state between the upper and lower spring seats and assists the damper
in controlling the body/axle movement. The upper and lower bushes are replaceable items.
Rubber bump stops are fitted to the chassis above each end of the axle. The bump stops are progressive in their
compression and prevent the axle from contacting the chassis in the event of maximum suspension travel being
reached. The bump stops revert to their original shape once the compression load has been removed from them.
The damper functions by restricting the flow of a hydraulic fluid through internal galleries within the damper body. A
chromium plated rod moves axially within the damper. As the rod moves, its movement is limited by the flow of fluid
through the galleries thus providing damping of undulations in the terrain. The damper rod is sealed at its exit point
from the body to maintain fluid within the unit and prevent the ingress of dirt and moisture. The seal also acts as a
wiper to keep the rod outer diameter clean. A plastic shroud protects the rod and slides over the body as the damper
moves. The coil spring aids the damper to extend after being compressed and also aids the damping process.

REAR SUSPENSION
DESCRIPTION AND OPERATION 64-7
Coil springs (vehicles without SLS)
On vehicles without SLS fitted, coil springs are fitted between the rear axle and the chassis in place of the SLS air
springs. Each spring is located at its base by the lower spring seat which is secured to a fabricated platform on the
rear axle with two bolts. The top of each spring is located in the upper spring seat. The upper spring seat comprises
a pressed metal plate with an outer coating of natural rubber bonded to the plate. The upper spring seat is retained
in position by the compression of the spring.
Coil Spring Specifications – Models up to 03 Model Year
The rear coil springs are of the variable rate type and are manufactured from silicon manganese 16.5 mm (0.65 in.)
diameter bar. Each spring has 9 coils and a free length of 385 mm (15.1 in.). The variable rate of the spring is achieved
by the active coils at one end being closer together. The rear coil spring is identified by a purple stripe painted on a
number of coils.
Coil Spring Specifications – Models From 03 Model Year
The introduction of the 03MY vehicle introduced a range of additional rear coil spring fitments. These were introduced
as a package to optimise vehicle trim heights.
The coil springs are manufactured from silicon manganese 16.35 mm (0.64 in.) diameter bar for springs on five seater
models and 16.57 mm (0.65 in.) diameter bar on seven seater models. The following spring data table shows the
colour codes, number of coils and spring free length.
Spring Data
The following table shows spring fitment applicability.
Spring Fitment Applicability
Watts linkage
A Watts linkage is used to ensure that the rear axle remains centrally located. The Watts linkage comprises two
transverse links and a pivot housing. The transverse links and pivot housing allow the rear axle to move vertically
without any transverse movement.
The transverse links are made from fabricated and welded steel. Each transverse link has a bush press fitted into a
housing at one end. The opposite end has a forked bracket with two cross holes.
The pivot housing is made from cast iron. Three bushes are press fitted in the housing, one in the centre and one at
each end.
Colour Code Total No. of Coils Free Length Model
Brown/Orange 8.73 384.7 mm (15.14 in) 5 Seat
Grey/Orange 8.73 392 mm (15.43 in) 5 Seat
Yellow/Grey 8.73 376.6 mm (14.82 in) 5 Seat
Pink/Grey 8.73 400.3 mm (15.75 in) 5 Seat
Blue/Grey 9.10 387.8 mm (15.26 in) 7 Seat
Green/Grey 9.10 395.2 mm (15.55 in) 7 Seat
White/Grey 9.10 380.6 mm (14.98 in) 7 Seat
Left Hand Drive Right Hand Drive
Both Sides RH Side LH Side
Brown/Orange Grey/Orange Yellow/Grey
Grey Orange Pink/Grey Brown/Orange
Blue/Grey Green/Grey White/Grey