MG Magnette KA Instruction Manual page 26

Running Adjustments.
Before dealing w i t h the detailed description and
dismantling o f the various units o f t h e chassis, the owner may require t o know
particulars of adjustments which he can effect.
I l l u s t r a t i o n 20.-View
adjusting t h e valve clearance.
b y single camshaft. By utilis
should never be undertaken
o f an M.G. Magnette engine, showing t h e operator i n the act o f
The removal o f cover discloses t h e fact t h a t t h e valve gear is operated
;ing an eccentric bush the valve clearance can be accurately set : this
unless t h e engine is hot.
Tappet Adjustment.
Before t h e owner has had an opportunity o f reading
through the whole manual he may require t o adjust his valves, and i n order that
he should know what is taking place, a careful examination o f Illustration No.
20
w i l l make the matter clear. H e w i l l probably be aware that there is a necessity
t o have a definite clearance between the cam and the valve rocker ; t h e various
parts are distinctly marked in t h e illustration. I t i s o f course important t o see
that the valve is properly seating when any adjustment is attempted, and this can
easily be seen by the position o f the cam in relation t o the rocker. There is a
single camshaft operating both t h e inlet and the exhaust valves. These are easily
distinguished from the fact that all the exhaust valves are on the near-side o f t h e
engine and t h e inlet valves on the of-side o f t h e engine. The valve rockers are
attached t o separate shafts at their outer extremity, and are provided w i t h eccentric
bushes. The opposite extremity of the rocker is wedge shaped, so that
if
t h e nut
which forms parts o f the eccentric bush is rotated, the wedge end o f t h e rocker
w i l l either advance o r recede from beneath the cam, and present a thicker o r
thinner section t o the face o f the cam when this rotates. The rocker is locked i n
position on the eccentric by means o f a locking screw, and in Illustration No.
20
a
spanner is shown i n position ready t o slack off the locking set screw. The eccentric
bush can then be rotated inside the rocker boss t o give the required clearance. See
that the bush does not rotate while t h e locking screw is being tightened.
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