LAND ROVER DISCOVERY 1999 Workshop Manual

ENGINE - V8
12-2-6 DESCRIPTION AND OPERATION
Description
General
The V8 petrol engine is an eight cylinder, water cooled unit having two banks of four cylinders positioned at 90 degrees
to each other. The engine comprises five main castings - two cylinder heads, cylinder block, timing cover and the oil
sump, all of which are manufactured from aluminium alloy.
NAS market vehicles from 03 model year receive a 4.6 litre version of the V8 engine to replace the previous 4.0 litre
version.
Cylinder heads
The cylinder heads are fitted with replaceable valve guides and valve seat inserts with the combustion chambers
formed in the head. Each cylinder head is sealed to the cylinder block with a gasket. The exhaust manifolds are bolted
to the outside of each cylinder head whilst the inlet manifolds are located in the centre of the 'Vee' and are bolted to
the inside face of each head. Inlet and exhaust manifolds are sealed to the cylinder heads by means of gaskets.
Each cylinder has a single inlet and exhaust valve. The exhaust valves are of the 'carbon break' type, a recess on the
valve stem prevents a build-up of carbon in the valve guide by dislodging particles of carbon as the valve stem moves
up and down the guide. Inlet and exhaust valve stem oil seals are fitted at the top of each valve guide. Valve operation
is by means of rocker arms, push rods and hydraulic tappets. Each of the rocker arms is located on a rocker shaft
which is supported by means of pedestals bolted to the cylinder heads. A spring, positioned on either side of each
rocker arm, maintains the correct relative position of the arm to its valve stem. The rocker arms are operated directly
by the push rods which pass through drillings in the cylinder heads and cylinder block. The bottom end of each push
rod locates in a hydraulic tappet operated by the single, chain driven camshaft.
The rocker covers are bolted to the cylinder heads and are sealed to the heads by a rubber gasket. Stub pipes for
crankcase ventilation hose connections are fitted to each rocker cover, the pipe in the right hand cover incorporates
an oil separator. The engine oil filler cap is situated in the right hand cover.
Cylinder block and camshaft
The cylinder block is fitted with cast iron cylinder liners which are shrink fitted and locate on stops in the block. The
camshaft is positioned in the centre of the cylinder block and runs in one piece bearing shells which are line bored
after fitting. Camshaft end-float is controlled by a thrust plate bolted to the front of the cylinder block. A timing gear,
chain driven by the crankshaft timing gear is bolted to the front of the camshaft.
Crankshaft and main bearings
The crankshaft is carried in five main bearings. The upper main bearing shell locations are an integral part of the
cylinder block casting. The lower main bearing caps are bolted to the cylinder block on either side of the upper bearing
shell locations with an additional bolt being inserted into each cap from either side of the cylinder block. The rear
main bearing cap carries the crankshaft rear oil seal and is sealed to the cylinder block by means of cruciform shaped
seals in each side of the cap. Number four main bearing cap carries the stud fixing for the oil pick-up pipe. Lower
main bearing shells are plain whilst the upper shells have an oil feed hole and are grooved. Crankshaft end-float is
controlled by the thrust faces of the upper centre shell. The crankshaft timing gear is located on the front of the
crankshaft by means of a Woodruff key which is also used to drive the gear type oil pump. The flywheel/drive plate
carries the crankshaft position sensor reluctor ring and is dowel located and bolted to the flywheel.
Timing cover
The timing cover is bolted to the front of the cylinder block and is sealed to the block with a gasket. The disposable,
full flow oil filter canister is screwed on to the timing cover which also carries the oil pressure switch, oil pressure relief
valve and crankshaft front oil seal. The gear type oil pump is integral with the cover which also has an internal oilway
to direct oil from the oil cooler to the filter.
NOTE: Oil coolers are only fitted to vehicles up to VIN 756821.

ENGINE - V8
DESCRIPTION AND OPERATION 12-2-7
Oil sump
The oil sump is bolted to the bottom of the cylinder block and the timing cover and is sealed to both components with
a one piece gasket. A removable baffle to prevent oil surge is fitted in the sump. The oil pick-up pipe and strainer
assembly is positioned within the sump and is attached at the pick-up end to a stud screwed into number four main
bearing cap and at the delivery end to the oil pump. The oil drain plug is located in the bottom of the sump and is
sealed with a washer.
Pistons and connecting rods
Each of the aluminium alloy pistons has two compression rings and an oil control ring. The pistons are secured to the
connecting rods by semi-floating gudgeon pins. Each gudgeon pin is offset by 0.5 mm (0.02 in). The top of each piston
is recessed, the depth of recess determining the compression ratio of the engine. Plain, big-end bearing shells are
fitted to each connecting rod and cap.

ENGINE - V8
12-2-8 DESCRIPTION AND OPERATION
Lubrication
A - To oil cooler, B - From oil cooler
NOTE: The oil cooler is only fitted to vehicles up to VIN 756821.
1Rocker shaft assembly
2Hydraulic tappet
3Oil pump4Oil filter element
5Oil pick-up pipe and strainer
6Oil pressure switch

ENGINE - V8
DESCRIPTION AND OPERATION 12-2-9
Oil is drawn from the sump through a strainer and into the oil pump via the oil pick-up pipe. Pressurised oil from the
pump passes through the oil cooler (if fitted) mounted in front of the radiator and returns to the full flow oil filter
element. Oil from the filter passes into the main oil gallery and through internal drillings to the crankshaft where it is
directed to each main bearing and to the big-end bearings via numbers 1, 3 and 5 main bearings. An internal drilling
in the cylinder block directs oil to the camshaft where it passes through further internal drillings to the hydraulic
tappets, camshaft bearing journals and rocker shafts. Lubrication to the pistons, small ends and cylinder bores is by
oil grooves machined in the connecting rods and by splash.
Oil pressure switch
The oil pressure warning light switch registers low oil pressure in the main oil gallery on the outflow side of the filter.
Whilst the engine is running and oil pressure is correct, the switch is open. When the ignition is switched on or if oil
pressure drops below the pressure setting of the switch, the switch closes and the low oil pressure warning lamp
located in the instrument pack will illuminate.
Hydraulic tappets
1Clip
2Pushrod seat
3Inner sleeve
4Upper chamber5Non-return ball valve
6Spring
7Outer sleeve
8Lower chamber
The hydraulic tappet provides maintenance free, quiet operation of the valves. This is achieved by utilizing engine oil
pressure to eliminate the clearance between the rocker arms and valve stems. When the valve is closed, engine oil
pressure present in the upper chamber, passes through the non-return ball valve and into the lower chamber. When
the cam begins to lift the outer sleeve, the resistance of the valve spring, felt through the push rod and seat, causes
the tappet inner sleeve to move downwards inside the outer sleeve. This downwards movement closes the non-return
ball valve and increases the pressure in the lower chamber sufficiently to ensure that the valve is fully opened by the
push rod. As the tappet moves off the peak of the cam, the non-return ball valve opens thereby allowing the pressure
in both chambers to equalize. This ensures that the valve will be fully closed when the tappet is on the back of the
cam.
Crankcase ventilation
A positive crankcase ventilation system is used to vent crankcase gases to the air induction system. Gases are drawn
from the left hand rocker cover to a tapping in the throttle body. An oil separator is incorporated in the hose connection
stub pipe in the right hand rocker cover, gases from this connection are drawn to a tapping in the inlet manifold.

+ EMISSION CONTROL - V8, DESCRIPTION AND OPERATION, Crankcase Emission Control System.

ENGINE - V8
ADJUSTMENTS 12-2-11
ADJUST ME NTS
Engine oil pressure check
$% 12.90.09.01
Check
1.Remove oil pressure switch.

+ ENGINE - V8, REPAIRS, Switch - oil
pressure.
2.Connect pressure check kit LRT-12-052C
adaptor and gauge to oil pressure switch
position on timing gear cover.
3.Check and if necessary top up engine oil.
4.Run engine at idle speed and check that oil
pressure is within limits given.

+ GENERAL DATA, Engine - V8.
5.Switch off ignition.
6.Remove pressure check kit LRT-12-052C.
7.Clean oil spillage.
8.Fit oil pressure switch.

+ ENGINE - V8, REPAIRS, Switch - oil
pressure.
Adjust
1.If engine oil pressure is below figures given,
check condition of oil pump and/or main and
big end bearings.

ENGINE - V8
REPAIRS 12-2-13
REPAIRS
Seal - crankshaft - rear
$% 12.21.20
Remove
1. Automatic gearbox models:Remove
converter drive plate.

+ ENGINE - V8, REPAIRS, Plate - drive
- automatic.
2. Manual gearbox models:Remove flywheel.

+ ENGINE - V8, REPAIRS, Flywheel.
3.Carefully remove oil seal from cylinder block to
avoid damage to seal location or running
surface on crankshaft. Discard seal.Refit
1.Ensure both seal location and running surface
on crankshaft are clean.
2.Lubricate replacement oil seal with engine oil.
3.Lubricate seal guide LRT-12-095 with engine
oil, fit seal guide to crankshaft.
4.Fit oil seal squarely onto crankshaft and
remove seal guide LRT-12-095.
5.Fit seal into location using tools LRT-12-091
and LRT-99-003.
6. Automatic gearbox models:Fit converter
drive plate.

+ ENGINE - V8, REPAIRS, Plate - drive
- automatic.
7. Manual gearbox models:Fit flywheel.

+ ENGINE - V8, REPAIRS, Flywheel.

ENGINE - V8
12-2-14 REPAIRS
Gasket - cylinder head - LH
$% 12.29.02
Remove
1.Remove inlet manifold gasket.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Gasket - inlet
manifold - lower.
2.Noting their fitted order, disconnect ht leads
from spark plugs.
3.Remove bolt securing engine harness to rear
of cylinder head.
4. LH drive models: Remove brake servo heat
shield.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Heat shield -
brake servo - Without Secondary Air
Injection.
5.Remove 8 bolts securing exhaust manifold to
cylinder head, release manifold and collect 2
gaskets.6.Progressively remove 4 bolts securing the
rocker shaft and remove rocker shaft.
7.Remove push rods. Store push rods in their
fitted order.
8. Models with SAI: Using a 9 mm hexagonal
drive bit, remove 2 air injection adapters from
cylinder head; discard adapters.
Note: To release the adapter thread locking
agent and prevent damage to the cylinder
head, remove the adapters by alternately
loosening then tightening slightly. Repeat this
procedure until adapters are removed.
CAUTION: Do not use air tools to remove
adapters.

ENGINE - V8
REPAIRS 12-2-15
9.In the sequence shown, remove 10 bolts
securing the cylinder head to block. Discard the
bolts.
10.Remove cylinder head.
CAUTION: Support both ends of cylinder
head on blocks of wood.
11.Remove cylinder head gasket.
Refit
1.Clean mating faces of cylinder block and head
using suitable gasket removal spray and a
plastic scraper, ensure that bolt holes in block
are clean and dry. Clean mating faces of
cylinder head and exhaust manifold.
CAUTION: Do not use a metal scraper or
machined surfaces may be damaged.
2.Check head and block faces for warping and
pitting. If out of specification, renew head.
3. Models with SAI: Using a 5/8 in x 20 TPI
(threads per inch) UNF tap having a class 2A
thread, remove deposits from secondary air
injection adapter tappings in cylinder head.
CAUTION: Ensure that tap used has 20 TPI.4.Fit cylinder head gasket with the word 'TOP'
uppermost.
CAUTION: Gaskets must be fitted dry.
5.Carefully fit cylinder head and locate on
dowels.
6.Lightly lubricate new cylinder head bolt threads
with clean engine oil.
7.Noting that bolts 1, 3 and 5 are longer than the
remainder, fit cylinder head bolts and tighten in
the sequence shown to 20 Nm (15 lbf.ft) then
90° , and finally a further 90° .
CAUTION: Do not tighten bolts 180° in one
operation.
8. Models with SAI: Fit new air injection adapters
and using a 9 mm hexagonal drive bit, tighten
to 33 Nm (24 lbf.ft).
CAUTION: Do not use an air tool to tighten
adapters.
9.Clean push rods.
10.Lubricate ends of push rods with clean engine
oil.
11.Fit push rods in their removed order.
12.Clean bases of rocker pillars and mating faces
on cylinder head.
13.Clean contact surfaces on rockers, valves and
push rods.
14.Lubricate contact surfaces and rocker shaft
with clean engine oil.
15.Fit rocker shaft assembly and engage push
rods.
16.Fit rocker shaft bolts and progressively tighten
to 40 Nm (30 lbf.ft).