Replacing the Camshaft.
Swing all the valve rockers into position against
their respective valves and replace the camshaft with the two marked teeth
of its hevel wheel engaging on either side of the marked tooth of the driving
pinion. The camshaft hearing caps are tenoned into the bearing brackets
so
that there is no possibility of misalignment. Care should he exercised,
however, to tighten up the camshaft bearing cap nuts evenly. Each should
be given
a
partial turn at a time until all me perfectly tight.
Adjusting the Rockers.
In the process of grinding-in the valves
a
certain
r
,
amount of metal is always removed.
I
his tends to reduce the clearance
existing between the head of the valve and the under-surface of the rocker-
arm. It is essential for the proper functioning of the engine that this
clearance should not be less than
.U03",
and
it
is therefore necessary to check
the clearance of each valve with the feeler gauge attached to one of the special
rocker adjusting spanners. On one side of the rocker will he found
a
hexagon
steel nut and on the other side
a
similar bronze nut. Engage the plain rocker
adjusting spanner on the bronze nut and, holding
it
firmly in position,
slacken the stcel nut with the spanner having the feeler gauge. Withdrawing
the spanner from the steel nut, insert the feeler gauge between the valve rocker
and the cam-after seeing that the oeak of the cam for that particular valve
is pointing directly upwards-and rotate the bronze nut until the feeler gauge
can just be withdrawn easily. Now, holding the spanner engaging the bronze
nut exactly in this position, tighten up the steel lock nut. The clearance
should then again be checked to make sure that no movement of the setting
took place while the lock nut was being tightened up. When adjusting the
rockers it is essential to
scc that the thick part of the hearing is downwards
and not upwards. Then, after loosening the lock nut, the adjusting spanner
should always he pressed
dowzwards
to reduce the clearance. If pressing the
spanner downwards increases the clearance, then the eccentric is the wrong
way up and requires turning around, this being done by continuing to rotate
it
by pressing the spanner handle
downwards
until the clearance does close.
Replacing the Cylinder Head.
When a11 the valve clearances have been
correctly adjusted, the cylinder head is ready for replacement.
It is first of
all necessary thoroughly to clean the gasket and remove any carbon deposit
adhering to its edges, and to coat both sides of it with an even film of
Castille
soap. If the gasket has been in any way damaged during the removal of the
cylinder head, do not attempt to use it again, hut immediately procure a new
one. See that any new gasket does not burr up around the stud holes and
that the cylinder hore openings are clear of the cylinder hore themselves.
The gasket can then he located over the studs in the cylinder block and gently
pushed into position on to the upper face of the cylinder block. It will he
found convenient to use
a
short length of tubing (a box spanner does quite
well) over the studs to push the gasket in position. This should he done
very gently, taking care to keep the gaskct parallel with the cylinder head and
not to force one end or one side down before the other.
'Turn the camshaft until the timing marks on the spiral hevel drive gears
coincide, and rotate the engine by the starting handle until numbers one
and
four are at the very top of their stroke, with the metal electrode on the
distributor rotating arm pointing towards No.
1
contact stud (No.
1
cylinder
is the one nearest the radiator). This stud is easily located by tracing the
high tension lead from the sparking plug for No.
1
cylinder to its junction on
D/I
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