It is particularly important to check the cle:~r:~nces
100
miles or so after
grinding, as the valves have a tendency to
"
bed down," and
clearances
should be chec'rcd subsequently every
2,000
miles.
Engine Bearings.
The mileage which may be covered before the main
and
big-end hurings require attentioh will depend entirely uoon the care
given to correct Iuhrication and the
way
in which the car
i:,
driven, p:irticul:~rly
wheh ntN. Owners are not recommended to undertake this overhaul
themselves, p:~rticularly when the standardised charges allow such jobs to be
done cheaply ar~d efficiently by
M.G.
agents all over the country.
Clutch.
The clutch is provided with two friction surfaces. The driving
surfaces comprise two rings of bonded asbestos fabric, one attached to the
flywheel cover-plate and the other attached to the pressure plate.
Six driving
pins pass through the flywheel, pressure plate
nnd flywheel cover-plate, all of
which consequently revolve together.
The driven surfaces comprise both sides
of
a
single stescl disc splined to
the driven shaft.
Driving pressure for the clutch is derived from six helic:11
springs housed betwseen the pressure plate and the flywheel.
The clutch must be run dry, and persistent slipping of the clutch is usually
an
indication that oil has found its way ir~to the clutch compartment, in which
case
it
will be necessary to remove the drain plug in the bottom of the clutch
housing and drain away any oil which may be present.
Oil
which may then
be still adhering to the surface of the clutch plates will soon be burnt away
after
a
little use.
If
the clutch is allowed to slip continuously the centre driven plate verjr
quickly becomes excessively hot, and the heat and friction will very soon
destroy the surfaces of the fahric facings.
Clutches are correctly adjusted at the Works before the cnr is delivered.
In the early life of the car, hone~er,
a
certain amount of bedding down of the
friction srufaces takes pl:~ce, which will permit the pressure plate to take up
a
position nearer the withdrawal mechanism, and thus reduce the necessary
clearance between the withdrawal levers, the withdrawal race and the lever
restraining spri~lgs. If this c1ear:tnce is completely taken up and the with-
drawal levers actually bear either
against the restraining springs or against the
withdrawal race,
it
will be realised that a great deal of the spring pressure
which should be forcing the friction surfaces together will be dissipated at
these two points, thus preventing the clutch springs from exerting their full
pressure on the clutch plates. When this occurs, slipping of the clutch will
take place, and it will be necessary to readjust the clutch withdrawal
mechanism in order to obtain the required clearance.
Removal of the small rectangular plate
in
the top of the clutch housing
will give access to th'e adjustment for the withdraw:11 levers. The withdrawal
lever restraining springs are for the purpose of preventing the withdrawal
levers from being forced against the withdrawal race under the influence of
centrifugal action and thus produce undue wear of the race itself and the ends
of the levers. They are carefully positioned at the Works and should not be
interfered with.
If
on inspection it is found that there is no clearance at all
~/1
PAGE TWENTY-ONE
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