ELECTRICAL EQUIPMENT
operating conditions. There is also a
micrometer adjustment by means of which
fine alterations in timing can be made to
allow for changes in
running conditions,
e.g.,
state of carbonisation, change of fuel,
etc.
A
completely sealed metallised paper
capacitor is utilised. This has the property
of being self-healing
;
should the capacitor
break down, the metallic
film
around the
point of rupture is vaporised away by the
heat of the spark, so preventing a per-
manent short circuit. Capacitor failure
will be found to be most infrequent.
The
H.T.
pick-up brush is of a composite
construction, the top portion consisting of a
resistive compound and the lower of softer
carbon to prevent wear taking place on
the
rotor electrode. The resistive portion of
this carbon brush which is in circuit
between the coil and the distributor gives a
measure of radio interference suppression.
Under no circumstances must a short non-
resistive brush be used as a replacement for
one of these longer resistive brushes.
The Pre-tilted Contact Breaker Unit
During 1955 an imvroved contact breaker
unit w:s introducedon the DM2P4 distri-
butor. Important features of this pre-tilted
contact breaker unit are
:
improved sensi-
tivity of vacuum control and elimination of
any tendency for the moving contact
breaker plate to rock at high cam speeds.
Contact adjustment has also been simplified.
2.
ROUTINE MAINTENANCE
In general, lubrication and cleaning con-
stitute normal maintenance procedure.
(a) Lubrication--every
3,000
miles
Take great care to prevent oil or
grease from getting on or near the
contacts.
Add a few drops of thin machine oil
through the aperture at the edge of
the contact breaker to lubricate the
centrifugal timing control.
Smear the cam with Mobilgrease
No.
2.
Lift off the rotor arm and apply to the
spindle
a
few drops of Ragosine
Molybdenised non-creep oil or thin
machine oil to lubricate the cam
SCREW
SECURING
\
CABLE
Fig.
zz
Fitting
H.T.
Cables.
bearing. It is not necessary to remove
the exposed screw, since it affords a
clearance to permit the passage of oil.
Replace the rotor arm carefully, Iocat-
ing its moulded projection in the
keyway
h
the spindle and pushing it
on as far as it will go.
(b) Cleaningevery
6,000
miles
Thoroughly clean the moulded dis-
tributor cover, inside and out, with a
soft dry cloth, paying particular atten-
tion to the spaces between the metal
electrodes. Ensure that the carbon
brush moves freely in its holder.
Examine the contact breaker. The
contacts must be quite free from
grease or oil. If they are burned or
blackened, clean them with very fine
carborundurn stone or emery cloth,
then wipe with
a
petrol-moistened
cloth. Cleaning is facilitated by re-
moving the contact breaker lever. To
do this, remove the nut, washer,
insulating piece and connections from
the post to which the end of the contact
breaker spring is anchored. The contact
breaker lever may now be removed
from its pivot. Before refitting the
contact breaker, smear the pivot post
with Ragosine Molybdenised non-creep
oil or Mobilgrease No.
2.
After
cleaning, check the contact breaker
setting. Turn the engine by hand until
the contacts show the
maximum open-
ing. This should measure
0.014
to
0.016".
If the measurement is in-
correct, keep the engine in the position
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