Contact Breaker Ignition System - Opel Kadett Owner's Manual

Chapter 5 Part B:

Contact breaker ignition system

Contents
Condenser - testing, removal and refitting . . . . . . . . . . . . . . . . . . . . . .5
Contact breaker points - gap and dwell angle adjustment . . . . . . . . .3
Contact breaker points - removal and refitting . . . . . . . . . . . . . . . . . . .4
Distributor - overhaul . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Distributor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Degrees of difficulty
Easy, suitable for Fairly easy, suitable
novice with little for beginner with
experience some experience
Specifications
General
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Firing order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Distributor
Rotational direction of rotor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact breaker points gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timing* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
*Refer to text for information on usage of unleaded petrol
Ignition coil
Primary winding resistance (approximate) . . . . . . . . . . . . . . . . . . . . . . .
Secondary winding resistance (approximate) . . . . . . . . . . . . . . . . . . . . .
Torque wrench settings
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 General information
1 In order that the engine can run correctly it
is necessary for an electrical spark to ignite
the fuel/air mixture in the combustion
chamber at exactly the right moment in
relation to engine speed and load. The ignition
system is based on feeding low tension
voltage from the battery to the coil where it is
converted to high tension voltage. The high
tension voltage is powerful enough to jump
the spark plug gap in the cylinders many
times a second under high compression,
providing that the system is in good condition
and that all adjustments are correct.
2 The ignition system is divided into two
circuits, low tension and high tension.
3 The low tension circuit (sometimes known
as the primary) consists of the battery, lead to
the ignition switch, lead from the ignition
switch to the low tension or primary coil
windings, and the lead from the low tension
coil windings to the contact breaker points
and condenser in the distributor.
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Ignition HT coil - removal, testing and refitting . . . . . . . . . . . . . . . . . . .9
Ignition system - testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Ignition system check . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Ignition timing - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Fairly difficult,
suitable for competent
DIY mechanic
Distributor with mechanical contact breaker points
1-3-4-2 (No 1 at crankshaft pulley end of engine)
Anti-clockwise (viewed from cap)
0.4 mm
47 to 53º
10º BTDC (crankshaft pulley notch and timing cover rib in alignment)
1.2 to 1.6 ohm
7k ohms
Nm
40
4 The high tension circuit consists of the high
tension or secondary coil winding, the heavy
ignition lead from the centre of the coil to the
centre of the distributor cap, the rotor arm,
and the spark plug leads and spark plugs.
5 The system functions in the following
manner. Low tension voltage is changed in
the coil into high tension voltage by the
opening and closing of the contact breaker
points in the low tension circuit. High tension
voltage is then fed via the carbon brush in the
centre of the distributor cap to the rotor arm
of the distributor cap, and each time it comes
in line with one of the four metal segments in
the cap, which are connected to the spark
plug leads, the opening and closing of the
contact breaker points causes the high
tension voltage to build up, jump the gap from
the rotor arm to the appropriate metal
segment and so via the spark plug lead to the
spark plug, where it finally jumps the spark
plug gap before going to earth.
6 The ignition is advanced and retarded
automatically, to ensure that the spark occurs
at just the right instant for the particular load
at the prevailing engine speed.
Difficult, suitable for Very difficult,
experienced DIY suitable for expert
mechanic DIY or professional
lbf ft
30
7 The ignition advance is controlled both
mechanically and by a vacuum-operated
system. The mechanical governor comprises
two weights, which move out from the
distributor shaft as the engine speed rises due
to centrifugal force. As they move outwards
they rotate the cam relative to the distributor
shaft, and so advance the spark. The weights
are held in position by two light springs and it
is the tension of the springs which is largely
responsible for correct spark advancement.
8 The vacuum control
diaphragm, one side of which is connected
via a small bore tube to the carburettor, and
the other side to the contact breaker plate.
Depression in the inlet manifold and
carburettor, which varies with engine speed
and throttle opening, causes the diaphragm to
move, so moving the contact breaker plate,
and advancing or retarding the spark.
9 A resistance wire in the low tension feed to
the coil keeps the coil voltage down to 6V
during normal running. This wire is bypassed
when the starter motor is operating, to
compensate for reduced battery voltage.
5B•1
5B
consists of a