MG Midget J1 1933 Instruction Manual page 30

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 bevel wheel engaging o n either side of the marked tooth of the driving
pinion. T h e camshaft bearing caps are tenoned into the bearing brackets
SO
that there is no possibility of misalignment. Care should be exercised,
however, to tighten u p the camshaft bearing cap nuts evenly. Each should
be given a partial turn at a time until all are perfectly tight.
Adjusting the Rockers. I n the process of grinding-in the valves a certain
amount of metal is always removed. This tends t o reduce the cl'earance
existing between the head of the valve and th,e under-surface of the rocker-
arm. It is essential for the proper functioning of the engine that this
clearance should in any case not be less than
.004,
and it is th,erefore
necessary to check the dearance of each valve with a feeler gauge when the
CAMSHAFT IN POSITION
I
W' SPANNER
INLET PORTS ROCKER
engince is warm, preferably at about normal running temperature. O n the
o n e sid'e of the Rocker will be f o u n d
a
hexagon bronze nut and in the Rocker
itself a locking screw. Slacken off the locking screw with the $" Whitworth
Spanner provided and insert the feeler gauge between the Valve Rocker and
the Cam. After seeing that the peak of the Cam for that particular v a h e is
pointing upwards, engage the Rocker Adjusting Spanner o n the bronze nut
and rotate until the feeler gaugte can just be withdrawn easily. Now, holding
the spanner engaging the bronze nut exactly in this position, tighten up the
locking screw as shown in Illustration N o .
20.
T h e clearance should then
again be checked to make sure that no movement of the setting took place
while the lock screw was being tightened up. W h e n adjusting the Rockers
it is essential to ascertain that the thickened portion of the hronze nut is
downwards and not upwards. If this is correctly assembled the clearance
decreases with a downward movement of th'e adjusting spanner, hut
if
in-
correctly a similar movement increases the clearance and the eccentric
J / A PAGE TWENTY-THREE