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

							ENGINE
2
OVERHAUL Rocker shafts - dismantling
1.Remove and discard split pin from one end of
rocker shaft.
2.Remove plain washer, wave washer, rocker
arms, brackets and springs.Inspecting components
1.Thoroughly clean components.
2.Inspect each component for wear, in particular
rocker arms and shafts. Discard weak or
broken springs.
3.Inspect pushrod seats in rocker arms.
4.Check pushrods for straightness and inspect
ball ends for damage, replace as necessary. 
						

							ENGINE
OVERHAUL3
Rocker shafts - assembling
1.Assemble rocker shafts with identification
groove at one o’clock position with push rod
end of rocker arm to the right.
CAUTION: Incorrect assembly of rocker
shafts will lead to an oil feed restriction.
2.Fit new split pin to one end of rocker shaft.
3.Fit plain washer and wave washer.
4.Lubricate rocker arm bushes with engine oil.
5.Fit rocker arms with offsets as illustrated.
6.Assemble rocker arms, brackets and springs to
rocker shaft.
7.Compress springs, fit wave washer, plain
washer and secure with new split pin.Rocker shafts - refit
1.Lubricate pushrods with engine oil.
2.Fit pushrods in removed order.
3.Fit each rocker shaft assembly, ensuring
identification groove is uppermost and towards
front of engine on RH side and towards rear of
engine on LH side.
CAUTION: Incorrect fitment of rocker
shafts will lead to an oil feed restriction.
4.Fit bolts and starting at centre brackets, tighten
to 38 Nm (28 lbf.ft). 
						

							ENGINE
4
OVERHAUL 5.Clean gasket surface in rocker cover and on
cylinder head, ensure bolt holes are clean and
dry.
6.Fit new gasket, dry to rocker cover.
CAUTION: Replace cork gasket(s) with
modified gasket(s) which incorporate
compression limiters in the bolt holes.
7.Fit rocker cover to cylinder head, fit new
’patched’multi-hex bolts and tighten in
diagonal sequence to:
Stage 1 - 3 Nm (2.5 lbf.ft)
Stage 2 - 8 Nm (6 lbf.ft)
CAUTION: The 2 short bolts must be fitted
on side of cover nearest centre of engine.
Ensure that outer rim of gasket is correctly
positioned around periphery of rocker cover.
8.LH rocker shaft only:Align dipstick tube to
rocker cover, fit and tighten screw.CYLINDER HEAD
Cylinder head - remove
1.Remove rocker shaft assembly.
2.Mark heads LH and RH for reassembly.
Engines fitted with secondary air injection (SAI)
3.Using a suitable hexagonal drive bit, remove
and discard 2 secondary air injection adapters
from cylinder head.
NOTE: To release the adapter thread
locking agent and prevent damage to the
cylinder head, remove the adapters by
loosening then tightening slightly. Repeat this
procedure until the adapters are removed.
CAUTION: Do not use an air tool to
remove adapters. 
						

							ENGINE
OVERHAUL5
All engines
NOTE: RH cylinder head illustrated.
4.Using sequence shown, remove and discard
10 bolts securing cylinder head to cylinder
block.
5.Release cylinder head from 2 dowels and
remove cylinder head.
6.Remove and discard cylinder head gasket.
7.Repeat above procedures for remaining
cylinder head.Valves and springs - remove
1.Remove spark plugs.
2.Using valve spring compressorLRT-12-034or
a suitable alternative, compress valve spring.
3.Compress valve spring sufficiently to release
collets from valve spring cap.
4.Release spring compressor and remove
collets, valve, valve spring cap and valve
spring.
5.Repeat above operations for remaining valves.
NOTE: Keep valves, springs, caps and
collets in fitted order.
6.Remove and discard valve stem oil seals. 
						

							ENGINE
6
OVERHAUL Cylinder head - inspection
1.Clean all traces of gasket material from
cylinder head using a plastic scraper.
2.Check core plugs for signs of leakage and
corrosion, replace as necessary. Apply sealant,
Part number STC 50552 to threads of threaded
core plugs.
3.Check gasket face of each cylinder head for
warping, across centre and from corner to
corner.
Maximum warp = 0.05 mm (0.002 in)
4.Check cylinder head height at each end of
cylinder head:
A= 22.94 mm (0.903 in) - New
B= 62.56 mm (2.463 in) - New
5.Cylinder heads may be refaced:
Reface limit = 0.50 mm (0.02 in) from new
dimension 
						

							ENGINE
OVERHAUL7
Valves, valve springs and guides - inspection
Valves
NOTE: Two types of exhaust valve may be
fitted - standard valves A in illustration or
carbon break valves - B in illustration.
Carbon break valves may be identified by the
machined profile C on the valve stem. To prevent
exhaust valves sticking, standard exhaust valves
should be replaced with carbon break valves
during engine overhaul.
NOTE: Modified inlet valves, carbon break
exhaust valves and valve guides are fitted
to later engines. The modified exhaust
valves may be identified by measuring the
distance A from the valve head face to the top of
the undercut on the valve stem. Additionally, the
exhaust valves have a black nitrided finish whilst
the inlet valves have a chrome finish.
Early valves - dimensionA= 29.5 to 30.5 mm (1.16
to 1.20 in)
Later valves - dimensionA= 32.5 to 33.5 mm (1.28
to 1.32 in)The modified valves may be fitted to early engines in
engine sets provided that the modified valve guides
are also fitted.
Valve guides
NOTE: The modified valve guides fitted to
later engines are 5 mm (0.211 in) shorter
than the early type guides, the overall
length of the modified guide being 57 mm (2.24
in); the reduction in length being the distance
the guide protrudes into the combustion
chamber side of the cylinder head. The modified
guides may be fitted to early engines in engine
sets provided that the modified inlet and carbon
break exhaust valves are also fitted. 
						

							ENGINE
8
OVERHAUL
1.Remove carbon deposits from valve guides
using an 8.70 mm (0.34 in) diameter reamer
inserted from combustion face side of cylinder
head.
2.Clean valve springs, cotters, caps and valves.
Clean inlet valve guide bores. Ensure all loose
particles of carbon are removed on completion.
3.Check existing valve stem to guide clearances,
valve head diameters and fitted height of
valves using the following procedures.
4.Check valve head diameterA:
Inlet = 39.75 to 40.00 mm (1.56 to 1.57 in)
Exhaust = 34.226 to 34.48 mm (1.34 to 1.35 in)
5.Check valve stem diameterB:
Inlet = 8.660 to 8.680 mm (0.340 to 0.342 in)
Exhaust valves:
Standard and carbon break exhaust valves
fitted to early engines = 8.651 to 8.666 mm
(0.340 to 0.341 in)
Modified carbon break exhaust valves fitted to
later engines = 8.641 to 8.656 mm (0.336 to
0.340 in)
6.Check installed height of each valve:
Valve installed heightC:
Standard and carbon break valves fitted to
early engines = 47.63 mm (1.9 in)
Modified inlet and carbon break exhaust valves
fitted to later engines = 44.163 to 45.29 mm
(1.741 to 1.802 in) 
						

							ENGINE
OVERHAUL9
7.Check valve stem to guide clearanceDusing
the following procedures:
8.Insert each valve into its respective guide.
9.Extend valve head approximately 13 mm (0.6
in) out of valve seat and position a suitable dial
test indicator to rear of valve head.
10.Move valve towards front of cylinder head and
zero dial test indicator gauge ensuring that
stylus of gauge remains in contact with valve
head.
11.Move valve towards rear of cylinder head and
record gauge reading to give valve stem to
guide clearance:
Inlet valves - Early and later engines = 0.025 to
0.066 mm (0.001 to 0.002 in)
Exhaust valves:
Standard and carbon break exhaust valves
fitted to early engines = 0.038 to 0.078 mm
(0.0015 to 0.003 in)
Modified carbon break exhaust valves fitted to
later engines = 0.048 to 0.088 mm (0.0019 to
0.0035 in)
12.Repeat above procedures for each valve in
turn.
13.Renew valves, guides and valve seat inserts
as necessary.
CAUTION: If modified valves and guides
are to be fitted, they must be replaced in
engine sets.
14.Check condition of valve springs:
Free length = 48.30 mm (1.90 in)
Fitted length = 40.40 mm (1.60 in)
Load - valve closed = 339±10 N (76±2 lbf)
Load - valve open = 736±10 N (165±2 lbf)
NOTE: Valve springs must be replaced as
a complete set.Valve guides - renew
1.Using valve guide remover,LRT-12-037press
valve guide out into combustion face side of
cylinder head.
NOTE: Service valve guides are 0.025 mm
(0.001 in) oversize on outside diameter to
ensure interference fit.
2.Lubricate new valve guide with engine oil,
position guide with tapered portion leading to
valve spring side of cylinder head. 
						

							ENGINE
10
OVERHAUL
3.UsingLRT-12-039Apartially press guide into
cylinder head, remove tool.
4.FitLRT-12-208over valve guide and continue
to press guide into cylinder head until tool
LRT-12-039Acontacts toolLRT-12-208;
remove tools.
5.Check valve guide installed heightA= 15.0
mm (0.590 in)
6.Using piloted reamers, ream valve guides from
valve spring side of head in 2 stages, with the
final cut being 0.1 mm (0.004 in), to give a
finished internal diameter of 8.70 mm (0.34 in).
7.Remove all traces of swarf on completion.Valve seat inserts - inspection
1.Check valve seat inserts for pitting, burning
and wear. Replace inserts as necessary. 
						

							ENGINE
OVERHAUL11
Valve seat inserts - renew
NOTE: Service valve seat inserts are
available 0.025 mm (0.001 in) oversize on
outside diameter to ensure interference fit.
1.Remove worn valve seats.
CAUTION: Take care not to damage
counterbore in cylinder head.
2.Heat cylinder head evenly to approximately
120°C (250°F).
WARNING: Handle hot cylinder head with
care.
3.Using a suitable mandrel, press new insert fully
into counterbore.
4.Allow cylinder head to air cool.Valve seats and seat inserts - refacing
CAUTION: Renew worn valve guides and
seat inserts before lapping valves to their
seats.
1.Check condition of valve seats and valves that
are to be re-used.
2.Remove carbon from valve seats.
3.Reface valves as necessary. If a valve has to
be ground to a knife-edge to obtain a true seat,
fit a new valve.
Valve seating face angleA=45°