MG Magnette KA Instruction Manual page 88

Pre-selector Gearbox.
The latest type pre-selector gearbox, manufactured
under Wilson patents, fitted t o M.G. Magnette gears requires comparatively l i t t l e
instruction.
It
is as well, however, f o r t h e owner t o k n o w what i s taking place
inside the box during the operation o f
"
de-clutching " and selecting the gears.
The gears w o r k o n what is known as the epicyclic principle, or, as they are
sometimes called, planetary gears. The gear wheels are always in constant mesh, and
t h e action o f the gears takes place by the contraction o f a number o f brake bands
which grip a series o f brake-drums o r annulli, depending upon t h e position of
the selector lever ; o r i n other words, t h e selector lever predetermines which gear w i l l
be operated when the
' l
clutch
"
pedal i s pressed down while the engine is running,
and then the pedal let up i n the ordinary way. The t e r m
"
clutch
"
pedal is used
i n the sense that
it
is the medium which disengages the power f r o m t h e engine
and, while having the same effect as an ordinary clutch, operates, o f course, i n an
entirely different manner.
H o w t o operate the Controls. To start. Before starting the engine, see that
the hand brake is applied, make sure that the gear is i n neutral b y moving the pre-
selecting lever t o the neutral position, and depressing the pedal t o its full extent and
releasing it. Then start the engine and move the pre-selecting lever t o the first
gear position (or reverse, should it be required) and depress t h e pedal t o its full
extent and release
it,
controlling the final part o f the upward stroke o f the pedal
as one would when engaging a normal clutch. The car w i l l begin t o move i n
the gear selected.
To
change gear. W h i l s t the car is moving forward i n 1st speed, select 2nd, and
when this speed is required relieve t h e accelerator pedal, depress fully the
''
clutch
"
pedal and release
it,
controlling the final part o f t h e upward stroke o f t h e pedal as
when starting.
Proceed similarly for the engagement o f 3rd and 4th speeds.
W h e n changing up, it i s advisable t o relieve the foot f r o m the accelerator
pedal, and when changing down t h e accelerator pedal should remain partly de-
pressed, and by this method it w i l l be found that the smoothest changes are effected.
Should t h e gear fail t o engage o n account o f the pre-selector lever being between
the positions indicated, move pre-selector t o t h e correct position, depress and
release clutch pedal a second time.
It
is usual t o r u n o n t o p w i t h 3 r d selected and ready f o r an instantaneous change
when required.
It
should, however, be remembered t h a t complete declutching
f o r any purpose w i l l then cause the engagement o f 3rd speed, and the engine
should be accelerated t o ensure a smooth change.
There is n o need t o change speed merely because the selector has been moved,
and selection can be made long before the change is actually required. "Select
Early
"
should be kept i n mind and driving w i l l become much simpler.
A
slight pressure o n the pedal w i l l give free engine position.
Page Seventy-three