MG Magnette KA Instruction Manual page 47

Engine Dismantlement.
The principal external components o f t h e engine
having been dealt with, it is now proposed t o describe (in dismantling the engine
pictorially) t h e construction o f the engine and the method employed.
The first feature in dismantling is obviously t h e cylinder head. This
comprises t h e t i m i n g o f t h e valves, t h e dismantling of t h e valve gear, t h e grinding
o f the valves, t h e relationship o f t h e cylinder head t o t h e cylinder block, and t h e
method o f driving t h e camshaft.
The first thing that should be borne in mind is that considerable care has been
exercised in t h e design o f t h e engine t o render the operation o f valve timing as
simple as possible.
It
must be taken for granted that t h e drive f r o m t h e crankshaft
through t h e dynamo i s correct, and it follows, therefore, that when t h e dynamo
is i n a certain position there i s a definite relationship between the arms o f t h e
coupling on t h e t o p o f t h e dynamo and the position o f the piston in the cylinder.
The firing order is
1 , 4, 2, 6, 3, 5.
Illustration 28.-This should
be carefully studied because it
has t o d o w i t h t h e t i m i n g o f
t h e valves and shows t h e relative
position of t h e a r m o f t h e d y n a m o
coupling when t w o o f t h e pistons
are o n t o p dead centre. The
valve cover c o r k washer can be
seen and t h e type of gears em-
ployed t o drive t h e camshaft.
When the cross head of the dynamo coupling is in the position shown
in Illustration No. 28, that i s t o say with the bolt through the coupling
attached t o the dynamo towards the front of the car, then No.
I
piston
is on top dead centre.
The cross head coupling attached t o the dynamo is connected t o the coupling
driving t h e vertical spindle by means o f laminated steel discs, and when t h e overhead
valve camshaft cover is removed it w i l l be seen that there is a mark on t h e driving
bevel gear wheel which meshes w i t h the camshaft gear wheel, and
if
ever t h e
camshaft is removed, provided nothing else has been disturbed, these marks only
have t o coincide f o r t h e timing t o be correct.
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