1999 LAND ROVER DEFENDER engine

ENGINE
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DESCRIPTION AND OPERATION CYLINDER HEAD COMPONENTS
The cylinder head components are described below:
Cylinder head
The cylinder head is of aluminium construction. It is not possible to reface the cylinder head if it becomes worn or
damaged. An alloy camshaft carrier is bolted directly to the upper surface of the cylinder head. Two dowels are
included in the cylinder head upper face for correct location of the camshaft carrier.
The EU3 cylinder head has a single internal fuel rail for delivering fuel to the injectors and an external fuel pipe for
returning spill fuel back to the fuel connector block. Therefore, pre EU3 and EU3 cylinder heads are not
interchangeable.
CAUTION: The cylinder head incorporates drillings for the fuel injection system, any
contamination which enters these drillings could cause engine running problems or injector
failure. It is therefore, essential that absolute cleanliness is maintained when carrying out work on
the cylinder head.
The camshaft carrier and cylinder head assembly is attached to the cylinder block by twelve cylinder head
retaining bolts which pass through the camshaft carrier and the cylinder head to secure the assembly to the
cylinder block.
CAUTION: The valve heads, tips of the injectors and glow plugs protrude below the face of the
cylinder head and will be damaged if the cylinder head is stored face down.
The camshaft is located between the cylinder head and the camshaft carrier, and the bearing journals are line
bored between the two components to form a matched pair.
CAUTION: Always fit plugs to open connections to prevent contamination.
The valve guides and valve seat inserts are sintered components which are an interference fit to the cylinder
head. The cylinder head machining also provide the locations for the electronic unit injectors, glow plugs, hydraulic
lash adjusters, finger followers and low pressure fuel rail.
Cooling to the cylinder head is provided by coolant flow through a water jacket machined into the cylinder head.
Drillings through the block provide lubrication channels for pressurised oil supply to cylinder head components
such as the lash adjusters, finger followers, rocker arms and camshaft bearings.
A coolant outlet elbow is fitted to the front LH side of the cylinder head to allow flow of coolant from the cylinder
head back to the radiator. A metal gasket is used to seal the joint between the water outlet elbow and the cylinder
head. A coolant temperature sensor is located in a port in the side of the water outlet elbow for monitoring coolant
temperature.
A stub pipe is connected at the front RH side of the cylinder block above the timing cover which connects a pipe to
supply oil to the vacuum pump. The timing chain tensioner adjuster is screwed in a thread in the cylinder head at a
location on the front RH side of the engine below the oil feed port for the vacuum pump.
An access hole for the camshaft gear is included at the front of the cylinder head which is sealed with a plastic
plug and rubber’O’ring. A press-fit core plug for the chain chest is located on the front face of the cylinder head.
A press-fit core plug for the cylinder head water jacket is located at the rear of the cylinder head and a threaded
brass plug for the water jacket is located on the LH side of the cylinder head beneath the exhaust manifold
assembly.
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12ENGINE
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DESCRIPTION AND OPERATION Fuel connector block
Type A - Non EU3 Models - Engine Serial No. Prefixes 10P to 14P
Type B - EU3 Models - Engine Serial No. Prefixes 15P to 19P
1.Fuel connector block assembly
2.Outlet stub pipe
3.Stub pipe - to fuel cooler4.Fuel temperature sensor
5.Fuel pressure regulator
6.Spill return fuel connection (EU3 models only)
A cast and machined aluminium alloy fuel connector block assembly is located at the rear RH side of the cylinder
head, attached by three flanged bolts. A metal gasket is used to seal the faces between the fuel connector block
and the cylinder head, which must be replaced every time the fuel connector block is removed.
CAUTION: The cylinder head incorporates drillings for the fuel injection system, any
contamination which enters these drillings could cause engine running problems or injector
failure. It is therefore, essential that absolute cleanliness is maintained when carrying out work on
the cylinder head.
CAUTION: The valve heads, tips of the injectors and glow plugs protrude below the face of the
cylinder head and will be damaged if the cylinder head is stored face down.
Camshaft carrier
The cast aluminium alloy camshaft carrier is bolted to the cylinder head by thirteen screws. The camshaft carrier
and cylinder head assembly is attached to the cylinder block by twelve cylinder head retaining bolts which pass
through the camshaft carrier and the cylinder head to secure the assembly to the cylinder block.
The carrier is machined together with the cylinder head to form a matched pair for carrying the camshaft.
Non-return valve
A non-return valve is located at the front, bottom LH side of the cylinder head. The non-return valve prevents oil
from draining from the lash adjusters and is an integral component within the cylinder head and is
non-serviceable.
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ENGINE
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DESCRIPTION AND OPERATION Camshaft
The camshaft is machined from cast steel and is located between the cylinder head and the camshaft carrier and
the six bearing journals are line bored between the two components to form a matched pair. The machined
camshaft has 15 lobes. Ten lobes operate the inlet and exhaust valves through hydraulic lash adjusters and finger
followers which are located below the camshaft. Five larger lobes activate the injector rockers which are located
above the camshaft on the rocker shaft and are used to generate fuel pressure in the EUI injectors.
The camshaft sprocket is driven via a Duplex chain connected to the crankshaft sprocket at a speed ratio of 2:1.
The camshaft sprocket is fixed to the front end of the camshaft by three bolts.
Camshaft lubrication is by splash and channel fed via pressurised oil flowing through galleries in the cylinder head.
Rocker shaft and rocker arms
Type A - Non EU3 Models - Engine Serial No. Prefixes 10P to 14P
Type B - EU3 Models - Engine Serial No. Prefixes 15P to 19p
1.Rocker arm adjusting screw
2.Rocker shaft
3.Rocker arm
4.EUI pin and roller assembly
5.Roller pin retention slug6.Camshaft lobe
7.Injector spring
8.Injector push-rod
9.Adjusting nut
The hollow rocker shaft is located in the camshaft carrier in six fixed mountings which sit above the camshaft. Six
bolts are used to lock the rocker shaft to the camshaft carrier. The front rocker shaft bearing has a ring dowel
located at the front rocker shaft mounting of the camshaft carrier for rocker shaft alignment. Two circlips hold each
rocker arm in position at the relevant positions on the rocker shaft.
CAUTION: The rocker shaft from a pre EU3 engine must not be fitted to an EU3 engine. This is
because the stroke of the EU3 injector has increased which requires the rocker to articulate over a
larger angle.
The camshaft end of each rocker arm features a roller which is free to rotate about a pin which passes through
two webs in the rocker arm, the roller pins are held in place by an interference fit retention slug passing through a
hole in the front web of each rocker arm.
To correctly function against the higher loads of the EU3 engine the geometry of the contact between the injector
pushrod and rocker arm adjusting screw has been modified. Both designs of adjusting screw are separately
available, with the EU3 version identified by an engraved dimple on the slotted end.
Rocker shaft and rocker arm lubrication is by splash and channel fed via pressurised oil flowing through galleries
in the cylinder head and through the rocker shaft.
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12ENGINE
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DESCRIPTION AND OPERATION Inlet and exhaust valves
The inlet and exhaust valves are mounted directly above the engine block cylinders.
Each valve is a forged and ground solid one-piece head and stem which is hardened by heat treatment. The
stems are chrome-plated then ground for improved heat transfer, wear resistance and smooth operation. It is not
possible to recut the valve’s face angle, but the valves can be lapped to their seats using grinding paste.
The valve springs are made from spring steel and are of the parallel single-coil type. The bottom end of the spring
rests on the flange of a spring seal which has a centre bore that locates on a recess ground into the lower valve
stem. The top end of the spring is held in place by a spring cap which is held in position at the top end of the valve
stem by split taper collets. The taper collets have grooves on the internal bore that locate in grooves ground into
the upper stems of the valves.
The valve seats and valve guides are sintered and are an interference fit into the cylinder head. The valve seats
and guides are non-serviceable.
Finger followers and lash adjusters
1.Valve stem
2.Finger follower
3.Lash adjuster plunger4.Oil supply hole
5.Lash adjuster body
The valves are operated through finger followers and lash adjusters, actuated by the camshaft lobes. When the
camshaft lobe presses down on the top of a finger follower roller mechanism, the respective valve is forced down
opening the inlet or exhaust port.
The lash adjuster body contains a plunger and two chambers for oil feed and pressurised oil. Pressurised oil is
supplied to the lash adjusters via the oil galleries in the cylinder head and through a hole in the side of the lash
adjuster body. The oil passes into a feed chamber in the lash adjuster then through to a separate pressure
chamber via a one way ball valve. Oil flow from the pressure chamber is determined by the amount of clearance
between the lash adjuster outer body and the centre plunger, oil escapes up the side of the plunger every time the
lash adjuster is operated, the downward pressure on the plunger forcing a corresponding amount of oil in the lash
adjuster body to be displaced. When the downward pressure from the camshaft and finger follower is removed
(i.e. after the trailing flank of the camshaft lobe has passed), oil pressure forces the lash adjuster’s plunger up
again. This pressure is not sufficient to effect the valve operation, but eliminates the clearance between the finger
follower and top of the valve stem.
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ENGINE
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DESCRIPTION AND OPERATION Timing chain guides
1.Hydraulic tensioner
2.Adjustable tensioner arm
3.Duplex timing chain4.Camshaft sprocket
5.Fixed tensioner arm
6.Crankshaft sprocket
The crankshaft sprocket to camshaft sprocket timing chain is held taut by a tensioner arm acting on the slack side
of the chain. The tensioner is automatically adjusted by means of an hydraulically operated tensioner adjuster.
The drive side of the chain has a plastic guide attached to the front face of the cylinder block. The fixed guide is
attached to the front of the engine block by two bolts. The tensioner arm is fixed to the front of the cylinder block
by a single pivot bolt which allows the tensioner arm to pivot about its axis.
NOTE: The adjustable tensioner arm is not interchangeable between pre-EU3 and EU3 vehicles
due to a change in geometry on the EU3 version.
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12ENGINE
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DESCRIPTION AND OPERATION CAMSHAFT COVER COMPONENTS
The camshaft cover cover components are described below:
Camshaft cover
The camshaft cover is cast from aluminium alloy and is fixed to the camshaft carrier / cylinder head assembly by
thirteen bolts. The cover has spacers and sealing washers inserted into each of the thirteen bolt holes.
A breather hose is connected to a port at the top of the camshaft cover by means of a hose clip which vents
crankcase gases back to the air intake via a breather valve in the air intake tract, located forward of the
turbocharger in the flexible air intake duct.
A rubber seal is fitted between the camshaft cover and camshaft carrier.
An oil filler aperture is included in the top of the camshaft cover, which is sealed with a plastic cap with integral
rubber seal.
CAMSHAFT TIMING CHAIN COMPONENTS
The timing chain cover and timing chain components are described below:
Timing chain cover
The timing chain cover is cast and machined aluminium alloy and is attached to the cylinder head by a bolt at the
RH top of the cover and by a stud and nut at the LH top of the cover. Eight screws are used to attach the timing
chain cover to the front of the engine block. The timing cover is located to the cylinder block front face by two
dowels.
A viscous fan is attached to an idler pulley at the front of the engine block. The fan bearing is located on a shaft
and held in place by a circlip and a bearing flange, the inner race of the fan bearing is an interference fit on the
shaft. The fan idler pulley is attached to the bearing hub by three bolts and the fan itself is secured to the pulley
and bearing shaft by a left-hand threaded nut.
The front of the crankshaft passes through a hole in the lower part of the timing cover. An oil seal is pressed into a
recess in the front of the timing cover to seal the interface between the front of the crankshaft and the timing
cover.
A stub pipe is fitted to the front RH side of the timing cover which is used to attach the oil drain pipe from the
vacuum pump by means of a hose and spring clip.
Timing chains
The timing chain between the camshaft and crankshaft sprockets is a duplex type, each chain having 56 links.
The timing chain is contained between a fixed plastic guide and an hydraulically adjustable plastic tensioner arm
which are attached to the front of the engine block.
To cope with the higher injection loads of the EU3 engine, the timing drive between the camshaft and crankshaft
has been upgraded. This requires thicker chain links to be used, therefore the individual pre EU3 and EU3
components are not interchangeable.
To distinguish between the two timing chains the links are different colours. A pre EU3 chain has blue links. An
EU3 chain has bronze links.
The oil pump timing chain is a single type and traverses the oil pump sprocket and the rear crankshaft sprocket.
The timing chains are oil lubricated, with oil being provided by a chain lubrication jet and from oil flow returning
back to the sump from the cylinder head. An oil hole is included at the front left hand side of the cylinder head
which supplies oil from the cylinder head oil galleries.
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ENGINE
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DESCRIPTION AND OPERATION Tensioner adjuster
1.Oil supply hole
2.Tensioner adjuster body3.Tensioner adjuster plunger
4.Sealing ring
The tensioner adjuster is hydraulically operated, oil enters the adjuster from the pressurised oil supply flowing
through the cylinder head to operate a plunger which pushes against a pivoting plastic tensioner arm. The lateral
movement in the tensioner arm causes the timing chain to tension and consequently compensation for chain
flutter and timing chain wear is automatically controlled. The adjuster is located at the front right hand side of the
cylinder head, just above the timing chain cover and below the vacuum pump oil feed port. The adjuster body is
threaded and screws into a tapping in the cylinder head. Holes are contained in the adjuster body to receive oil
from the cylinder head galleries, the oil pressure is used to force the plunger out of the adjuster body to press the
tensioner arm against the timing chain and so using the oil trapped in the adjuster body to act as a damper.
The internal damping of the hydraulic tensioner is tuned for each application. This means that pre-EU3 and EU3
components are not interchangeable.
Drive train sprockets
The camshaft sprocket has a double row of teeth which locate with the duplex timing chain. The sprocket is fitted
to the camshaft by three bolts.
The oil pump sprocket is located on the front of the oil pump housing by a single retaining bolt. The sprocket has a
single row of teeth which locates with the oil pump drive chain.
The crankshaft sprocket contains three rows of teeth, the rear row locates on the single oil pump chain and the
front two rows locate with the duplex timing chain. The crankshaft sprocket has a slot in its internal diameter which
locates with the Woodruff key on the crankshaft. The front of the crankshaft sprocket has a timing mark.
As a consequence of thicker chain links being used on EU3 vehicles, the thickness of the camshaft and crankshaft
sprocket teeth has been reduced. Individual pre-EU3 and EU3 components are therefore not interchangeable.
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12ENGINE
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DESCRIPTION AND OPERATION CYLINDER BLOCK FLOW
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