Land Rover V8 engine 4.0, 4.6 litre. Manual — part 7
ENGINE
10
OVERHAUL
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 angle A = 45
°
ENGINE
OVERHAUL
11
4. Cut valve seats using LRT-12-501 with
LRT-12-503 and LRT-12-517.
Valve seat:
Width A:
Inlet = 36.83 mm (1.45 in)
Exhaust = 31.50 mm (1.24 in)
Seating width B:
Inlet = 0.89 to 1.4 mm (0.035 to 0.055 in)
Exhaust = 1.32 to 1.83 mm (0.052 to 0.072 in)
Angle C= 56
°
to 70
°
Angle D= 46
°
to 46
°
25’
Angle E= 20
°
5. Ensure cutter blades are correctly fitted to
cutter head with angled end of blade
downwards, facing work, as illustrated. Check
that cutter blades are adjusted so that middle
of blade contacts area of material to be cut.
Use light pressure and remove only minimum
of material necessary.
6. Remove all traces of swarf on completion.
ENGINE
12
OVERHAUL
Valves - lapping-in
1. Lap each valve to its seat using fine grinding
paste.
2. Clean valve and seat.
3. Coat valve seat with a small quantity of
engineer’s blue, insert valve and press it into
position several times without rotating. Remove
valve and check for even and central seating.
Seating position shown by engineer’s blue
should be in centre of valve face.
4. Check valve installed height if valve seats have
been recut or new valves or valve seat inserts
have been fitted.
Valve installed height A= 47.63 mm (1.9 in) -
maximum
5. Thoroughly clean cylinder head, blow out
oilways and coolant passages.
Valves and springs - refit
1. Fit new valve stem oil seals, lubricate valve
stems, fit valves, valve springs and caps,
compress valve springs using LRT-12-034
and fit collets.
2. Using a wooden dowel and mallet, lightly tap
each valve stem two or three times to seat
valve cap and collets.
3. Fit spark plugs and tighten to 20 Nm (15 lbf.ft).
ENGINE
OVERHAUL
13
Cylinder head - refit
1. Clean cylinder block and cylinder head faces
using suitable gasket removal spray and a
plastic scraper.
2. Eensure that bolt holes in cylinder block are
clean and dry.
CAUTION: Do not use metal scraper or
machined surfaces may be damaged.
3. Fit cylinder head gasket with the word ’TOP’
uppermost.
NOTE: Gasket must be fitted dry.
4. Carefully fit cylinder head and locate on
dowels.
5. Lightly oil threads of new cylinder head bolts.
NOTE: RH cylinder head illustrated.
6. Fit new cylinder head bolts:
Long bolts: 1, 3 and 5
Short bolts: 2, 4, 6, 7, 8, 9 and 10
7. Using sequence shown, tighten cylinder head
bolts to:
Stage 1 - 20 Nm (15 lbf.ft)
Stage 2 - 90 degrees
Stage 3 - Further 90 degrees
CAUTION: Do not tighten bolts 180
°
in one
operation.
8. Fit rocker shaft assembly.
9. Repeat above procedures for remaining
cylinder head.
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