Land Rover 4 0 4 6 V8 Engine Overhaul 4th Edition Rover Manual

							ENGINE
32
OVERHAUL PISTONS, CONNECTING RODS, PISTON RINGS
AND CYLINDER BORES
Pistons and connecting rods - remove
1.Remove cylinder head(s).
2.Remove big-end bearings.
3.Remove carbon ridge from top of each cylinder
bore.
4.Suitably identify each piston to its respective
cylinder bore.
5.Push connecting rod and piston assembly to
top of cylinder bore and withdraw assembly.
6.Repeat above procedure for remaining pistons.
CAUTION: Big-end bearing shells must be
replaced whenever they are removed.Piston rings - remove
1.Using a suitable piston ring expander, remove
and discard piston rings.
2.Remove carbon from piston ring grooves.
NOTE: Use an old broken piston ring with
a squared-off end.
CAUTION: Do not use a wire brush. 
						

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Piston rings - inspection
1.Temporarily fit new compression rings to
piston.
NOTE: If replacement pistons are to be
fitted, ensure rings are correct for piston.
The 2nd compression ring marked’TOP’must be
fitted, with marking uppermost, into second
groove. The 1st compression ring fits into top
groove and can be fitted either way round.
2.Check compression ring to groove clearance:
1st compression ringA= 0.05 to 0.10 mm
(0.002 to 0.004 in).
2nd compression ringB= 0.05 to 0.10 mm
(0.002 to 0.004 in).
3.Insert piston ring into its relevant cylinder bore,
held square to bore with piston and check ring
gaps.
1st compression ring = 0.30 to 0.50 mm (0.012
to 0.02 in)
2nd compression ring = 0.40 to 0.65 mm
(0.016 to 0.03 in)
Oil control ring rails = 0.38 to 1.40 mm (0.014
to 0.05 in)
4.Retain rings with their respective pistons.Pistons - remove
1.Clamp hexagon body ofLRT-12-013in vice.
2.Screw large nut back until flush with end of
centre screw.
3.Push centre screw forward until nut contacts
thrust race.
4.Locate remover/replacer adapter
LRT-12-126/2with its long spigot inside bore
of hexagon body.
5.Locate piston and connecting rod assembly on
centre screw and up to adapterLRT-12-126/2
ensuring that prongs of adapter are positioned
on piston either side of gudgeon pin.
6.Fit remover/replacer bushLRT-12-126/1on
centre screw with flanged end away from
gudgeon pin.
7.Screw stop nut on to centre screw.
CAUTION: Ensure that LRT-12-126/1 is
correctly located in gudgeon pin bore of
piston.
8.Lock the stop nut securely with the lockscrew.
9.Push connecting rod to right to locate end of
gudgeon pin in adapterLRT-12-126/2.
10.Ensure thatLRT-12-126/1is still located in
gudgeon pin bore of piston.
11.Screw large nut up toLRT-12-013.
12.Hold lockscrew and turn large nut until
gudgeon pin is withdrawn from piston.
CAUTION: Ensure that prongs of adapter
LRT-12-126/2 remain in contact with piston
and do not contact gudgeon pin. 
						

							ENGINE
34
OVERHAUL 13.Dismantle toolLRT-12-013and remove piston,
connecting rod and gudgeon pin.
NOTE: Keep each piston and gudgeon pin
with their respective connecting rod.
14.Repeat above operations for remaining
pistons.Pistons - inspection
1.Clean carbon from pistons.
2.Inspect pistons for distortion, cracks and
burning.
3.Measure and record piston diameter at 90°to
gudgeon pin axis and 10 mm (0.4 in) from
bottom of skirt.
4.Check gudgeon pin bore in piston for signs of
wear and overheating.
NOTE: Pistons fitted on production are
graded’A’or’B,’the grade letter is
stamped on the piston crown.
Production piston diameter:
GradeA= 93.970 to 93.985 mm (3.700 to 3.7002 in)
GradeB= 93.986 to 94.00 mm (3.7003 to 3.701 in)
GradeBpistons are supplied as service
replacements. Worn cylinder liners fitted with grade
’A’pistons may be honed to accept grade’B’
pistons provided that specified cylinder bore and
ovality limits are maintained.
CAUTION: DO NOT attempt to de-glaze
cylinder bores.
CAUTION: Ensure replacement pistons are
correct for the compression ratio of the
engine. The compression ratio will be
found on the cylinder block above the engine
serial number. Ensure that replacement
connecting rods are correct length for engine
being overhauled.
Connecting rod length between centres:
4.0 litre = 155.12 to 155.22 mm (6.10 to 6.11 in)
4.6 litre = 149.68 to 149.78 mm (5.89 to 5.91 in) 
						

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OVERHAUL35
Gudgeon pins - inspection
NOTE: Gudgeon pins are only supplied as
an assembly with replacement pistons.
1.Check gudgeon pins for signs of wear and
overheating.
2.Check clearance of gudgeon pin in piston.
Gudgeon pin to piston clearance = 0.006 to
0.015 mm (0.0002 to 0.0006 in).
3.Check overall dimensions of gudgeon pin.
Overall length = 60.00 to 60.50 mm (2.35 to 2.4
in).
Diameter - measured at each end and centre
of pin = 23.995 to 24.00 mm (0.94 to 0.95 in).Cylinder liner bore - inspection
1.Measure cylinder liner bore wear and ovality in
two axis 40 to 50 mm (1.5 to 1.9 in) from top of
bore.
Cylinder liner bore:
Grade’A’piston fitted = 94.00 to 94.015 mm
(3.700 to 3.701 in)
Grade’B’piston fitted = 94.016 to 94.030 mm
(3.7014 to 3.702 in)
Maximum ovality = 0.013 mm (0.0005 in)
Cylinder liners having grade’A’pistons fitted
may be honed to accept grade’B’pistons
provided specified wear and ovality limits are
maintained.
CAUTION: The temperature of piston and
cylinder block must be the same to ensure
accurate measurement. DO NOT attempt
to de-glaze cylinder bores.
2.Check alignment of connecting rods. 
						

							ENGINE
36
OVERHAUL Pistons - refit
CAUTION: Pistons have a 0.5 mm (0.02 in)
offset gudgeon pin which can be identified
by an arrow mark on the piston crown.
This arrow MUST always point to the front of the
engine.
1.Assemble pistons to connecting rods with
arrow on piston pointing towards domed
shaped bosses on connecting rod for RH bank
of cylinders, and arrow pointing away from
dome shaped bosses for LH bank of cylinders.
2.Clamp hexagon body ofLRT-12-013in vice.
3.Screw large nut back until flush with end of
centre screw.
4.Locate remover/replacer adapter
LRT-12-126/2with its long spigot inside bore
of hexagon body.
5.Fit parallel sleeve, part of toolLRT-12-013with
grooved end towards open end ofLRT-12-013
up to shoulder of centre screw.
6.Lubricate gudgeon pin and bores of connecting
rod and piston with graphited oil.7.Locate connecting rod and piston to centre
screw with connecting rod entered on parallel
sleeve up to the machined groove on the
sleeve.
CAUTION: Ensure that the parallel sleeve
used is the same diameter as the gudgeon
pin.
8.Fit gudgeon pin on to centre screw and into
piston bore up to connecting rod.
9.Fit remover/replacer bushLRT-12-126/1with
flanged end towards gudgeon pin.
10.Screw the stop nut on to the centre screw and
position piston against remover/replacer
adapterLRT-12-126/2.
CAUTION: Ensure that prongs of
LRT-12-126/2 remain in contact with piston
and do not contact the gudgeon pin.
11.Lock the stop nut securely with the lockscrew.
12.Lubricate centre screw threads and thrust race
with graphited oil, screw large nut up to
LRT-12-013.
13.Set torque wrench to 16 Nm (12 lbf.ft), and
using socket on large nut, pull gudgeon pin in
until flange ofLRT-12-126/1is distance’A’
from face of piston.
Distance’A’= 0.4 mm (0.016 in).
CAUTION: If torque wrench’breaks’
during above operation, fit of gudgeon pin
to connecting rod is not acceptable and
components must be replaced. The centre screw
and thrust race must be kept well lubricated
throughout operation.
14.Dismantle toolLRT-12-013, remove piston,
check no damage has occurred during
pressing and piston moves freely on gudgeon
pin.
15.Repeat above operations for remaining
pistons. 
						

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OVERHAUL37
Piston to cylinder bore clearance - checking
1.Starting with number 1 piston, invert piston and
with arrow on piston crown pointing towards
REAR of cylinder block, insert piston in cylinder
liner.
2.Position piston with bottom of skirt 30 mm (1.2
in) from top of cylinder block.
3.Using feeler gauges, measure and record
clearance between piston and left hand side of
cylinder - viewed from front of cylinder block:
Piston to bore clearance = 0.015 to 0.045 mm
(0.001 to 0.002 in)
4.Repeat above procedures for remaining
pistons.Pistons and connecting rods - refit
1.Fit oil control ring rails and expander, ensuring
ends butt and do not overlap.2.Fit 2nd compression ring marked’TOP’with
marking uppermost into second groove.
3.Fit 1st compression ring into first groove either
way round.
4.Position oil control expander ring joint and ring
rail gaps all at one side, between gudgeon pin
and away from left hand (thrust) side of piston -
viewed from front of piston. Space gaps in ring
rails approximately 25 mm (1.0 in) each side of
expander ring joint.
5.Position compression rings with ring gaps on
opposite sides of piston between gudgeon pin
and right hand side of piston - viewed from
front of piston.
6.Thoroughly clean cylinder bores.
7.Lubricate piston rings and gudgeon pin with
engine oil.
8.Lubricate cylinder bores with engine oil. 
						

							ENGINE
38
OVERHAUL
9.Fit ring clamp to piston and compress piston
rings.
NOTE: Connecting rods shown in final
fitted positions.
10.Insert connecting rod and piston assembly into
respective cylinder bore ensuring domed
shaped boss on connecting rod faces towards
front of engine on RH bank of cylinders, and
towards rear on LH bank of cylinders.
11.Fit big-end bearing caps and bearing shells.
12.Fit cylinder head(s).FLYWHEEL AND STARTER RING GEAR
Flywheel - remove
1.Restrain flywheel and remove 6 bolts securing
flywheel.
2.Remove flywheel.
NOTE: Dowel located. On early engines,
balance weights are on engine side of
flywheel, replacement flywheels will have
balance weights on clutch side. 
						

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OVERHAUL39
Flywheel and starter ring gear - inspection
1.Inspect flywheel face for cracks, scores and
overheating. The flywheel can be refaced on
the clutch face providing thickness does not go
below minimum.
Flywheel minimum thicknessA= 40.45 mm
(1.6 in)
2.Inspect starter ring gear for worn, chipped and
broken teeth.
CAUTION: Do not attempt to remove
reluctor ring.
3.Renew starter ring gear if necessary.Starter ring gear - renew
1.Drill a 6 mm (0.250 in) diameter hole at root of
2 teeth.
CAUTION: Do not allow drill to enter
flywheel.
2.Secure flywheel in soft jawed vice.
3.Split ring gear using a cold chisel.
WARNING: Wear safety goggles and take
precautions against flying fragments when
splitting ring gear.
4.Remove flywheel from vice, remove old ring
gear, and place flywheel, clutch side down, on
a flat surface. 
						

							ENGINE
40
OVERHAUL
5.Heat new ring gear uniformly to between 170°
and 175°C (340°and 350°F).
CAUTION: Do not exceed this
temperature.
WARNING: Take care when handling hot
ring gear.
6.Locate ring gear on flywheel with chamfered
inner diameter towards flywheel flange.
NOTE: If ring gear is chamfered on both
sides, it can be fitted either way round.
7.Press ring gear on to flywheel until it butts
against flywheel flange.
8.Allow flywheel to air cool.Flywheel - refit
1.Ensure bolt holes are clean and dry.
2.Fit flywheel and locate on 2 dowels.
3.Fit flywheel bolts.
4.Using assistance, restrain flywheel and tighten
flywheel bolts to 78 Nm (58 lbf.ft). 
						

							ENGINE
OVERHAUL41
DRIVE PLATE AND RING GEAR ASSEMBLY
Drive plate and ring gear assembly - remove -
Drive plates fitted with shimmed hub aligner
1.Suitably identify each component to its fitted
position.
NOTE: 4.0 litre drive plate illustrated.
2.Remove 4 bolts securing drive plate assembly.
3.Remove clamp ring and drive plate assembly.
NOTE: Drive plate assembly is dowel
located.
4.Remove 6 socket head Allen bolts securing
hub aligner to crankshaft, remove hub aligner
and selective shim; retain shim.
NOTE: Dowel located.Drive plate and ring gear assembly - remove -
Drive plates with unshimmed hub aligner and
later engines fitted with modified’one-piece’
starter ring gear
NOTE: Later engines are fitted with a
modified’one-piece’starter ring gear
which incorporates the reluctor plate,
spacer and hub. The modified ring gear may be
fitted as a replacement to engines with
unshimmed hub aligners.
1.Suitably identify each component to its fitted
position.
Early engines with unshimmed hub aligner
NOTE: 4.0 litre drive plate illustrated.
2.Remove 4 bolts securing clamp ring, drive
plate, spacer and ring gear assembly to hub
aligner.
3.Remove clamp ring, drive plate, spacer and
ring gear assembly.
NOTE: Ring gear assembly is dowel
located.
4.Remove 6 Allen bolts securing hub aligner to
crankshaft, remove hub aligner.
NOTE: Dowel located.