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Page H3
Cylinder Head ..\-faintenance-eontinued
Should it be necessary to remove these covers
ncw copper joints should be fitted when they are
replaced.
lf ncw copper joints are not available the old
unes may be used provided they are softened
before being re-fitted.
To soften the joints heat them to a dull red heat
and quench in cold water.
Special care is necessary when refitting these
covers to ensure that there are no leaks at the
joints otherwise there will be a loss of compression
and the efficiency of the engine -:vill be impaired.
Re-assembly Cylinder Head.
Replace valves, valve springs, collars and collet~.
Replace combustion chamber caps and joints.
Fit exhaust manifold gaskets and exhaust
manifold.
To tighten the cylinder head Duts, a torque wrench
should be used, set to the tension given in Section B,
and pulled down in the order marked in Fig. H.3.
With tb. push rods in position replace tbe rocker
shaft assembly. Examine the oil pipe union and
ensure that it is in good condition. Connect
union to cylinder head.
Where necessary, re-connect the pipe from the
pneumatic governor to the venturi.
Replace atomisers (See Section S).
Replace leak off pipes and cold starting equip-
ment.
For fitting of fuel pipes see Section S.
Valve Clearance.
Valve clearances should be set to .010 in. (.25 mIn)
When adjusting valve clearances the engine
should he turned to bring the respective pistons to
T .D.C. on compression.
To adjust, slacken the lock nut and with a .010 in.
(.25 mm) feeIer gauge between the top of the valve
stem and the rocker lever face, turn the adjusting
screw by means of a screwdriver until the correct
clearance is obtained. Tighten the lock-nut.
STARTING THE ENGINE
Proceed as instructed in Section C.
Af ter warming up, tbe engine should be sbut
down and the cylinder head Duts again tightened
witb a torque wrench, set to the tension given in
Section B. The nuts should be tightened in the
order shown in Fig. H.3.
Re-set valve clearance to .010 in. (.25 mm).
Tbe cylinder head cover cao aow be replac~d.
A ncw joint should be fitted and care should b~
taken to sec that it is correctly positioned
Replacing Cylinder Head.
Before replacing cylinder head it is extremely
important to ensure that the cylinder block and
cylinder head races are perfectly clean.
When replacing the cylinder head a new gasket
should be used. Cover both sides with a thin
coating of good jointing compound and before
placing over the cylinder head studs ensure that
the gasket is correctly positioned. The gasket is
marked to indicate hcw it should be replaced.
Having placed the gas ket in position ensure that
the cylinder bead face is perfectly clean and place
in position over the cylinder head studs.
§
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[J.-
@~6
2~
."
Fig. H3. Diagram showing order in which cylinder head
nut.! must bc tightened
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