Rear disc - DOHC models
Removal
15Where applicable, remove the roadwheel
bolt and spacer used when checking the disc.
16Remove the disc pads, as described in
Section 5.
17Remove the brake caliper with reference
to Section 9, but leave the hydraulic fluid pipe
connected. Move the caliper to one side, and
suspend it using wire or string to avoid
straining the pipe.
18Remove the securing screw and withdraw
the disc from the hub (see illustration). If the
disc is tight, collapse the handbrake shoes by
inserting a screwdriver through the adjuster
hole in the disc and turning the adjuster
wheel.
Refitting
19Refitting is a reversal of removal, but
make sure that the mating faces of the disc
and hub are perfectly clean, and apply a little
locking fluid to the threads of the securing
screw. Refit the disc pads, as described in
Section 5.
11Brake drum - removal,
inspection and refitting
3
Note: When working on the brake
components, take care not to disperse brake
dust into the air, or to inhale it, since it may
contain asbestos, which can damage your
health.
Removal
1Where applicable, remove the wheel trim,
then loosen the relevant rear roadwheel bolts
and chock the front wheels. Jack up the rear
of the vehicle, and support on axle stands
(see “Jacking and Vehicle Support”)
positioned under the body side members.
Remove the roadwheel.
2Fully release the handbrake.
3Extract the drum securing screw and
remove the drum. If the drum is tight, remove
the plug from the inspection hole in the brake
backplate, and push the handbrake operating
lever towards the brake shoe to move theshoes away from the drums. If necessary,
slacken the handbrake cable adjuster.
Inspection
4Brush the dirt and dust from the drum,
taking care not to inhale it.
5Examine the internal friction surface of the
drum. If they are deeply scored, or so worn
that the drum has become ridged to the width
of the shoes, then both drums must be
renewed.
6Regrinding of the friction surface is not
recommended, since the internal diameter of
the drum will no longer be compatible with the
shoe friction material contact diameter.
Refitting
7Refit the brake drum and tighten the
securing screw. If necessary, back off the
adjuster wheel until the drum will pass over
the shoes.
8Adjust the brakes by operating the
footbrake a number of times. A clicking noise
will be heard at the drum as the automatic
adjuster operates. When the clicking stops,
adjustment is complete.
9Refit the roadwheel and lower the vehicle to
the ground. Do not fully tighten the roadwheel
bolts until the vehicle is resting on its wheels.
12Rear wheel cylinder (drum
brakes) - removal, overhaul
and refitting
3
Note: Refer to the notes at the beginning of
Sections 3 and 11 before proceeding. Before
dismantling a wheel cylinder, check that
replacement parts can be obtained, and retain
the old components to compare them with the
new ones
Removal
1Where applicable, remove the wheel trim,
then loosen the relevant rear roadwheel bolts
and chock the front wheels. Jack up the rear
of the vehicle and support on axle stands (see
“Jacking and Vehicle Support”) positioned
under the body side members. Remove the
roadwheel.
2Fully release the handbrake.3Extract the drum securing screw and
remove the drum. If the drum is tight, remove
the plug from the inspection hole in the brake
backplate, and push the handbrake operating
lever towards the brake shoe to move the
shoes away from the drum. If necessary,
slacken the handbrake cable adjuster.
4Using a pair of pliers, unhook the upper
return spring from the brake shoes, noting its
orientation, then push the upper ends of the
shoes apart until they are clear of the wheel
cylinder (see illustration).
5Working under the bonnet, remove the
brake fluid reservoir cap and secure a piece of
polythene over the filler neck with a rubber
band, or by refitting the cap. This will reduce
the loss of fluid during the following
procedure.
6Unscrew the brake fluid pipe union nut from
the rear of the wheel cylinder, and disconnect
the pipe (see illustration). Take care not to
strain the pipe. Be prepared for fluid spillage,
and plug the open ends to prevent dirt ingress
and further fluid loss.
7Unscrew the two securing bolts from the
rear of the brake backplate, and withdraw the
wheel cylinder.
Overhaul
8If desired, the wheel cylinder can be
overhauled as follows. Otherwise, go on to
paragraph 17 for details of refitting.
9Brush the dirt and dust from the wheel
cylinder, but take care not to inhale it.
10Pull the rubber dust seals from the ends of
the cylinder body.
11The pistons will normally be ejected by
the pressure of the coil spring. If they are not,
tap the end of the cylinder body on a piece of
wood, or apply low air pressure (e.g. from a
foot pump), to the hydraulic fluid union hole in
the rear of the cylinder body, to eject the
pistons from their bores.
12Inspect the surfaces of the pistons and
their bores in the cylinder body for scoring, or
evidence of metal-to-metal contact. If evident,
renew the complete wheel cylinder assembly.
Note that the later type of wheel cylinder can
be used to replace the early type as a
complete unit.
Braking system 9•11
12.6 Unscrewing rear wheel cylinder brake
fluid pipe union12.4 Rear brake assembly
1 Wheel cylinder
2 Upper shoe return spring (note
orientation)
10.18 Withdrawing the rear brake disc -
DOHC model
9
Idle settings (continued)
Idle mixture (CO content):
20 NE and 20 SEH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.0 max.
20 XEJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.7 to 1.2%
All other models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.3 % (at 2800 to 3200 rpm)
Fuel Pressure (regulator vacuum hose connected)
Multec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.76 bar
Motronic 4.1:
Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.3 to 2.7 bar
Return . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.3 to 1.5 bar
Motronic 1.5:
Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.8 to 2.2 bar
Return . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.3 to 1.5 bar
Motronic 2.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.0 to 2.2 bar
Motronic 2.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.2 to 2.7 bar
Simtec 56.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .not available
Torque wrench settingsNmlbf ft
All specifications as for carburettor models except for the following:
Bracket, tank vent valve to coolant flange . . . . . . . . . . . . . . . . . . . . . . .86
Fuel distributor pipe to inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Fuel flow damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2015
Fuel injector retainer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Fuel pressure regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.52
Fuel pump clamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Idle air control stepper motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.52
Knock sensor (X16 SZ) to block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1310
Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3022
Throttle body mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2015
Throttle body upper-to-lower section . . . . . . . . . . . . . . . . . . . . . . . . . . .64.5
Throttle potentiometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21.5
Throttle valve housing to inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . .97
1General description
General
1All engines available within the Cavalier
range can be operated on unleaded petrol.
Refer to Chapter 5 for further details. Note
that models fitted with a catalytic converter
must only be operated on unleaded petrol,
and leaded petrol must not be used. Models
with catalytic converter can be identified by
the engine code, which is prefixed by the
letter ‘C’ or ‘X’.
Multec system
Note: There is no provision for the adjustment
or alteration of the idle speed; if checking the
idle speed, remember that it may vary
constantly under ECU control.
2The Multec system is essentially a simple
method of air/fuel metering, replacing the
carburettor with a single injector mounted in a
throttle body. This type of system is therefore
also known as Throttle Body Injection (TBi),
Central Fuel Injection (CFi) or single-(or
mono-) point injection. The whole system is
best explained if considered as three
sub-systems, these being fuel delivery, air
metering and electrical control.
3The fuel delivery system incorporates the
fuel tank (with the electric fuel pumpimmersed inside it), the fuel filter, the fuel
injector and pressure regulator (mounted in
the throttle body), and the hoses and pipes
connecting them. When the ignition is
switched on (or when the engine is cranking,
on X16 SZ engines) the pump is supplied with
voltage, by way of the pump relay and fuse
11, under the control of the Electronic Control
Unit (ECU). The pump feeds through the fuel
filter to the injector. Fuel pressure is controlled
by the pressure regulator, which lifts to allow
excess fuel to return to the tank.
4The air metering system includes the inlet air
temperature control system and the air
cleaner, but its main components are in the
throttle body assembly. This incorporates the
injector, which sprays fuel onto the back of the
throttle valve, the throttle potentiometer. This
is linked to the throttle valve spindle and sends
the ECU information on the rate of throttle
opening by transmitting a varying voltage. The
idle air control stepper motor is controlled by
the ECU to maintain the idle speed.
5The electrical side of the fuel injection
system consists of the ECU and all the
sensors that provide it with information, plus
the actuators by which it controls the whole
system’s operation. The basic method of
operation is as follows; note that the ignition
system is controlled by the same ECU.
6The manifold absolute pressure sensor is
connected by a hose to the inlet manifold.
Variations in manifold pressure are converted
into graduated electrical signals that are usedby the ECU to determine the load on the
engine. The throttle valve potentiometer is
explained above.
7Information on engine speed and
crankshaft position comes from the distributor
on C16 NZ engines and from the crankshaft
speed/position sensor on C16 NZ2, X16 SZ
and C18 NZ engines.
8An odometer frequency sensor provides the
ECU with information on the vehicle’s road
speed, and the coolant temperature sensor
provides it with the engine temperature. A
knock sensor located in the cylinder block
between cylinders 2 and 3 on the X16 SZ
engine provides additional information to the
ECU by detecting pre-ignition (detonation)
during the combustion process.
9All these signals are compared by the ECU
with set values pre-programmed (mapped)
into its memory. Considering this information,
the ECU selects the response appropriate to
those values. It controls the ignition amplifier
module by varying the ignition timing as
required. The fuel injector is controlled by
varying its pulse width the time the injector is
held open, to provide a richer or weaker
mixture, as appropriate. The idle air control
stepper motor controls the idle speed. The
fuel pump relay controls the fuel delivery and
the oxygen sensor, accordingly. The mixture,
idle speed and ignition timing are constantly
varied by the ECU to provide the best settings
for cranking, starting and engine warm-up
(with either a hot or cold engine), idling,
4B•2Fuel and exhaust systems - fuel injection models
4B
cruising and accelerating. The injector earth is
also switched off on the overrun to improve
fuel economy and reduce exhaust emissions.
Additionally, on the X16 SZ engine, the ECU
also controls the operation of the charcoal
canister purge valve in the evaporative
emission control system.
10The oxygen sensor screwed into the
exhaust manifold provides the ECU with a
constant feedback signal. This enables it to
adjust the mixture (closed-loop control) to
provide the best possible conditions for the
catalytic converter to operate effectively.
11Until the oxygen sensor is fully warmed up
it gives no feedback so the ECU uses
pre-programmed values (open-loop control) to
determine the correct injector pulse width.
When the sensor reaches its normal operating
temperature, its tip (which is sensitive to
oxygen) sends the ECU a varying voltage
depending on the amount of oxygen in the
exhaust gases. If the inlet air/fuel mixture is too
rich, the exhaust gases are low in oxygen so the
sensor sends a low-voltage signal. The voltage
rises as the mixture weakens and the amount of
oxygen rises in the exhaust gases. Peak
conversion efficiency of all major pollutants
occurs if the inlet air/fuel mixture is maintained
at the chemically correct ratio for the complete
combustion of petrol of 14.7 parts (by weight) of
air to 1 part of fuel (the “stoichiometric” ratio).
The sensor output voltage alters in a large step
at this point, the ECU using the signal change
as a reference point and correcting the inlet
air/fuel mixture accordingly by altering the fuel
injector pulse width.
12In addition, the ECU senses battery
voltage, incorporates diagnostic capabilities,
and can both receive and transmit information
by way of the diagnostic connector, thus
permitting engine diagnosis and tuning by
Vauxhall’s TECH1, test equipment.
Motronic system
13The Motronic type is available in several
different versions, depending on model. The
system is under the overall control of the
Motronic engine management system (Chapter
5), which also controls the ignition timing.
14Fuel is supplied from the rear-mounted
fuel tank by an electric fuel pump mounted
under the rear of the vehicle, through a
pressure regulator, to the fuel rail. The fuel rail
acts as a reservoir for the four fuel injectors,
which inject fuel into the cylinder inlet tracts,
upstream of the inlet valves. On SOHC
engines, the fuel injectors receive an electrical
pulse once per crankshaft revolution, which
operates all four injectors simultaneously. On
DOHC engines, sequential fuel injection is
used, whereby each injector receives an
individual electrical pulse allowing the four
injectors to operate independently, which
enables finer control of the fuel supply to each
cylinder. The duration of the electrical pulse
determines the quantity of fuel-injected, and
pulse duration is computed by the Motronic
module, based on the information received
from the various sensors.15On SOHC engines, inlet air passes from
the air cleaner through a vane type airflow
meter, before passing to the cylinder inlet
tracts through the throttle valve. A flap in the
vane airflow meter is deflected in proportion
to the airflow; this deflection is converted into
an electrical signal, and passed to the
Motronic module. A potentiometer screw
located on the airflow meter provides the
means of idle mixture adjustment, by altering
the reference voltage supplied to the Motronic
module.
16On DOHC engines, inlet air passes from
the air cleaner through a hot wire type air
mass meter, before passing to the cylinder
inlet tracts through a two-stage throttle body
assembly. The electrical current required to
maintain the temperature of the hot wire in the
air mass meter is directly proportional to the
mass flow rate of the air trying to cool it. The
current is converted into a signal, which is
passed to the Motronic module. The throttle
body contains two throttle valves that open
progressively, allowing high torque at part
throttle, and full-throttle, high-speed
“breathing” capacity. A potentiometer screw
located on the air mass meter provides the
means of idle mixture adjustment, by altering
the reference voltage supplied to the Motronic
module.
17A throttle position sensor enables the
Motronic module to compute the throttle
position, and on certain models, its rate of
change. Extra fuel can thus be provided for
acceleration when the throttle is opened
suddenly. Information from the throttle
position sensor is also used to cut off the fuel
supply on the overrun, thus improving fuel
economy and reducing exhaust gas
emissions.
18Idle speed is controlled by a variable-
orifice solenoid valve, which regulates the
amount of air bypassing the throttle valve. The
valve is controlled by the Motronic module;
there is no provision for direct adjustment of
the idle speed.
19Additional sensors inform the Motronic
module of engine coolant temperature, air
temperature, and on models fitted with a
catalytic converter, exhaust gas oxygen
content.
20A fuel filter is incorporated in the fuel
supply line, to ensure that the fuel supplied to
the injectors is clean.
21A fuel pump cut-off relay is controlled by
the Motronic module, which cuts the power to
the fuel pump should the engine stop with the
ignition switched on, if there is an accident. All
1993-onwards models equipped with
Motronic systems, have their fuel pump
located inside the fuel tank.
22The later M2.8 system is basically the
same as the earlier M2.5 system apart from
the following:
a)Hot Film Mass Airflow Meter - The hot
wire type unit used previously is replaced
on the M2.8 system by a hot film mass
airflow meter. The operation is the sameexcept that a thin, electrically heated plate
rather than a wire is used. The plate is
maintained at a constant temperature by
electric current as the inlet air mass
passing over the plate tries to cool it. The
current required to maintain the
temperature of the plate is directly
proportional to the mass flow rate of the
inlet air. The current is converted to a
signal that is passed to the Motronic
module.
b)Inlet Air Temperature Sensor -The sensor
is located in the hose between the hot
film mass airflow meter and the air cleaner
for precise monitoring of inlet air
temperature. Signals from the sensor are
used in conjunction with other sensors to
indicate the occurrence of a hot start
condition. The Motronic module then
interprets these signals to alter injector
duration accordingly.
c)Throttle Valve Potentiometer -On the
M2.8 system a throttle valve
potentiometer replaces the throttle valve
switch used previously.
Simtec system
23An increased amount of electronic
components are used instead of mechanical
parts as sensors and actuators with the
Simtec engine management system. This
provides more precise operating data as well
as greater problem free motoring.
24The control unit is equipped with
electronic ignition control. Called ‘Micropro-
cessor Spark Timing System, inductive
triggered’, (or MSTS-i), and means that the
mechanical high voltage distributor is no
longer needed. It is located behind the trim
panel, on the right-hand side footwell (door
pillar).
25The ignition coil is replaced by a dual
spark ignition coil, which is switched directly
by the output stages in the control unit.
26A camshaft sensor will maintain
emergency operation, should the crankshaft
inductive pulse pick-up, malfunction. These
sense TDC (‘Top Dead Centre’), crankshaft
angle and engine speed. The signals are used
by the control unit to calculate ignition point
and for fuel injection.
27The ‘hot film airflow meter’ determines the
mass of air taken in by the engine. The system
uses this information to calculate the correct
amount of fuel needed for injection in the
engine.
28The air inlet temperature sensor (NTC), is
fitted in the air inlet duct between the air
cleaner and the hot mass air flow meter.
29A controlled canister purge valve is
actuated by the system. The tank ventilation is
monitored closely with the Lambda control (or
oxygen sensor) and adaptation by the
computer within the control unit.
30A knock control system is also fitted. This
eliminates the need for octane number
adjustment, as it is performed automatically
through the control unit.
Fuel and exhaust systems - fuel injection models 4B•3
Compression ratio
14 NV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.4 : 1
16 SV, X16 SZ, 18 SV and 20 SEH . . . . . . . . . . . . . . . . . . . . . . . . . .10.0 : 1
C16 NZ, C16 NZ2, C18 NZ, 20 NE and C20 NE . . . . . . . . . . . . . . . . .9.2 : 1
Maximum power:
14 NV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 kW (75 bhp) at 5600 rpm
16 SV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 kW (82 bhp) at 5400 rpm
X16 SZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 kW (71 bhp) at 5000 rpm
C16 NZ and C16 NZ2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 kW (75 bhp) at 5200 rpm
18 SV and C18 NZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66 kW (90 bhp) at 5400 rpm
20 NE and C20 NE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 kW (116 bhp) at 5200 rpm
20 SEH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 kW (129 bhp) at 5600 rpm
Maximum torque:
14 NV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 Nm at 3000 rpm
X16 SZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128 Nm at 2800 rpm
16 SV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130 Nm at 2600 rpm
C16 NZ and C16 NZ2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125 Nm at 2800 rpm
18 SV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148 Nm at 2800 rpm
C18 NZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145 Nm at 3000 rpm
20 NE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175 Nm at 2600 rpm
20 SEH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180 Nm at 4600 rpm
C20 NE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 Nm at 2600 rpm
Firing order:
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3-4-2 (No 1 cylinder at timing belt end)
Cylinder block:
Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cast iron
Maximum permissible bore out-of round . . . . . . . . . . . . . . . . . . . . . .0.013 mm
Maximum permissible bore taper . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.013 mm
Maximum permissible rebore oversize . . . . . . . . . . . . . . . . . . . . . . . .0.5 mm
Crankshaft and bearings
Number of main bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Main bearing journal diameter (mm):
14 NV, 16 SV, C16 NZ and X16 SZ
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54.980 to 54.997
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54.730 to 54.747
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54.482 to 54.495
C16 NZ2, 18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57.974 to 57.995
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57.732 to 57.745
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57.482 to 57.495
Main bearing shell colour codes:Bearing cap shellsCylinder block shells
14 NV, 16 SV, C16 NZ and X16 SZ
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BrownGreen
0.25 mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Brown/blueGreen/blue
0.50 mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Brown/whiteGreen/white
C16 NZ2, 18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Brown/green/white
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Brown/blue and Green/blue
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Brown/white and Green/white
Centre (thrust) main bearing journal width (mm):
14 NV, 16 SV, C16 NZ and X 16 SZ
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26.000 to 26.052
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26.200 to 26.252
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26.400 to 26.452
C16 NZ2, 18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25.950 to 26.002
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26.150 to 26.202
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26.350 to 26.402
Big-end bearing journal diameter (mm):
14 NV, 16 SV, C16 NZ and X16 SZ
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.971 to 42.987
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.721 to 42.737
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.471 to 42.487
C16 NZ2, 18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48.970 to 48.988
0.25mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48.720 to 48.738
0.50mm undersize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48.470 to 48.488
2A•2SOHC engine procedures
Piston rings
Number (per piston) (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 compression, 1 oil control
Ring end gap (mm):
Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.3 to 0.5
Oil control (top and bottom sections) . . . . . . . . . . . . . . . . . . . . . . . . .0.4 to 1.4
Ring gap offset (to gap of adjacent ring)* . . . . . . . . . . . . . . . . . . . . . .180º
* See Section 32 for oil control ring sections
Cylinder head
Material (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Light alloy
Maximum permissible distortion of sealing face (all models) . . . . . . . . .0.025 mm
Height of cylinder head (sealing surface to sealing surface) (all models) . .96.00 ±0.25 mm
Valve seat width (mm):
14 NV, 16 SV, C16 NZ, X 16 SZ and C16 NZ2
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.3 to 1.5
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.6 to 1.8
18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.0 to 1.5
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.7 to 2.2
Camshaft
Camshaft bearing journal diameter:Normal (mm)0.1 mm undersize
14 NV, 16 SV, C16 NZ and X16 SZ:
No 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39.435 to 39.455
No 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39.685 to 39.705
No 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39.935 to 39.955
No 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40.185 to 40.205
No 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40.435 to 40.455
C16 NZ2, 18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH:
No 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.455 to 42.47042.355 to 42.370
No 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.705 to 42.72042.605 to 42.620
No 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.955 to 42.97042.855 to 42.870
No 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43.205 to 43.22043.105 to 43.120
No 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43.455 to 43.47043.355 to 43.370
Camshaft bearing diameter in housing:
14 NV, 16 SV, C16 NZ and X16 SZ:
No 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39.500 to 39.525
No 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39.750 to 39.775
No 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40.000 to 40.025
No 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40.250 to 40.275
No 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40.500 to 40.525
C16 NZ2, 18 SV, C18 NZ, 20 NE, C20 NE and 20 SEH:
No 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.500 to 42.52542.400 to 42.425
No 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.750 to 42.77542.650 to 42.675
No 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43.000 to 43.02542.900 to 42.925
No 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43.250 to 43.27543.150 to 43.175
No 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43.500 to 43.52543.400 to 43.425
Cam lift (mm):
14 NV (inlet and exhaust) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.12
16 SV and C16 NZ:
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.61
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.12
C16 NZ2, 18 SV and C18 NZ
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.01
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.39
C20 NE and 20 NE (inlet and exhaust) . . . . . . . . . . . . . . . . . . . . . . . .6.67
20 SEH (inlet and exhaust) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.70
Maximum permissible radial run-out (mm) (all models) . . . . . . . . . . . . .0.04
Endfloat (mm) (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.09 to 0.21
Timing belt (engines without automatic tension roller)
Tension, using Vauxhall gauge KM-51 0-A (see Section 11):
14NV, 16 SV and C16 NZ:
New belt, cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5
New belt, warm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.0
Used belt, cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.0
Used belt, warm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7.0
2A•4SOHC engine procedures
31Refit the previously removed
components, referring to the relevant
Sections of this Chapter.
35Crankshaft and bearings -
examination
4
Examination
1Examine the crankpin and main journal
surfaces for signs of scoring or scratches, and
check the ovality and taper of the crankpins
and main journals. If the bearing surface
dimensions do not fall within the tolerance
ranges given in the Specifications at the
beginning of this Chapter, the crankpins
and/or main journals will have to be reground.
2Big-end and crankpin wear is accompanied
by distinct metallic knocking, particularly
noticeable when the engine is pulling from low
revs, and some loss of oil pressure.
3Main bearing and main journal wear is
accompanied by severe engine vibration rumble
- getting progressively worse as engine rev’s
increase - and again by loss of oil pressure.
4If the crankshaft requires regrinding, take it
to an engine reconditioning specialist, who
will machine it for you and supply the correct
undersize bearing shells.
5Inspect the big-end and main bearing shells
for signs of general wear, scoring, pitting and
scratches. The bearings should be matt grey
in colour. With leadindium bearings, should a
trace of copper colour be noticed, the
bearings are badly worn, as the lead bearing
material has worn away to expose the indium
underlay. Renew the bearings if they are in
this condition, or if there are any signs of
scoring or pitting. You are strongly advised
to renew the bearings - regardless of their
condition at time of major overhaul.
Refitting used bearings is a false economy.
6The undersizes available are designed to
correspond with crankshaft regrind sizes. Thebearings are in fact, slightly more than the
stated undersize, as running clearances have
been allowed for during their manufacture.
7Main and big-end bearing shells can be
identified as to size by the marking on the
back of the shell. Standard size shell bearings
are marked STD or .00, undersize shells are
marked with the undersize such as 0.020 u/s.
This marking method applies only to
replacement bearing shells, and not to those
used during production.
8An accurate method of determining bearing
wear is by using a Plastigage. The crankshaft
is located in the main bearings (and, if
necessary, the big-end bearings), and the
Plastigage filament is located across the
journal. Vauxhall recommend that the
crankshaft journal and bearing shells are
lightly lubricated, to prevent the Plastigage
from tearing as the bearing cap is removed.
The bearing cap should be fitted, and the
bolts tightened to the specified torque. The
cap is then removed, and the width of the
filament is checked against a scale that shows
the bearing running clearance. The clearance
should be compared with that given in the
Specifications.
9Where applicable, check the teeth of the
crankshaft TDC sensor wheel for damage
(see illustration). If evident, the crankshaft
must be renewed.
10Similarly, check the condition of the pins
in the front crankshaft balance weight, which
serve as detect points for the plug-in
diagnostic sensor used by Vauxhall dealers
(see illustration).
36Cylinder block and bores -
examination and renovation
4
Examination
1Examine the cylinder bores for taper,
ovality, scoring and scratches. Start bycarefully examining the top of the cylinder
bores. If they are at all worn, a very slight
ridge will be found on the thrust side. This
marks the top of the piston ring travel. The
owner will have a good indication of the bore
wear before dismantling the engine, or
removing the cylinder head. Excessive oil
consumption, accompanied by blue smoke
from the exhaust, is a sure sign of worn
cylinder bores and piston rings.
2Measure the bore diameter across the
block, and just below any ridge. This can be
done with an internal micrometer or a dial
gauge. Compare this with the diameter of the
bottom of the bore, which is not subject to
wear. If no measuring instruments are
available, use a piston from which the rings
have been removed, and measure the gap
between it and the cylinder wall with a feeler
blade. Refer to the Specifications. If the
cylinder wear exceeds the permitted
tolerances, then the cylinders will need
reboring, in which case note the following
points:
a)Piston and cylinder bores are closely
matched in production. The actual
diameter of the piston is indicated by
numbers on its crown; the same numbers
stamped on the crankcase indicate the
bore diameter
b)After reboring has taken place, the
cylinder bores should be measured
accurately and oversize pistons selected
from the grades available to give the
specified piston-to-bore clearance
c)For grading purposes, the piston diameter
is measured across the bottom of the skirt
3If the wear is marginal and within the
tolerances given, new special piston rings can
be fitted to offset the wear.
4Thoroughly examine the crankcase and
cylinder block for cracks and damage, and
use a piece of wire to probe all oilways and
waterways to ensure that they are
unobstructed.
SOHC engine procedures 2A•33
35.10 Check the condition of the pins (arrowed) in the front
crankshaft balance weight - 2.0 litre SOHC engine35.9 Check the condition of the TDC sensor wheel teeth at the
front of the crankshaft - 2.0 litre SOHC engine
2A
REF
Overall length: *
Saloon models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4432 mm
Hatchback models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4352 mm
Overall width: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1876 mm
Overall height (unladen): *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1400 mm
Wheelbase: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2600 mm
Track:
Front: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1426 mm
Rear: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1423 mm
Ground clearance (minimum): *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 mm
Weights
Kerb weight: *
Dependent on model . . . . . . . . . . . . . . . . . . . . . . . . . .1098 ± 101 kg
Maximum gross vehicle weight: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Refer to VIN plate
Maximum roof rack load: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 kg
Maximum towing hitch downward load: *
All models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 kg
Maximum towing weight: *
Trailer with brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . .1175 ± 175 kg
Trailer without brakes . . . . . . . . . . . . . . . . . . . . . . . . . . .550 ± 50 kg
* Exact details depend upon model and specification.
Refer to owners handbook.
Dimensions and Weights . . . . . . . . . . . . . . . . . .REF•1
Conversion Factors . . . . . . . . . . . . . . . . . . . . . . .REF•2
Buying Spare Parts . . . . . . . . . . . . . . . . . . . . . . .REF•3
Vehicle Identification . . . . . . . . . . . . . . . . . . . . . .REF•3
General Repair Procedures . . . . . . . . . . . . . . . . .REF•4
Jacking and Vehicle Support . . . . . . . . . . . . . . .REF•5Radio/cassette unit Anti-theft System . . . . . . . .REF•5
Tools and Working Facilities . . . . . . . . . . . . . . . .REF•6
MOT Test Checks . . . . . . . . . . . . . . . . . . . . . . . .REF•8
Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . .REF•12
Glossary of Technical Terms . . . . . . . . . . . . . . .REF•20
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .REF•25
Reference REF•1
Dimensions and Weights
MOTTest Checks REF•11
MExamine the handbrake mechanism,
checking for frayed or broken cables,
excessive corrosion, or wear or insecurity of
the linkage. Check that the mechanism works
on each relevant wheel, and releases fully,
without binding.
MIt is not possible to test brake efficiency
without special equipment, but a road test can
be carried out later to check that the vehicle
pulls up in a straight line.
Fuel and exhaust systems
MInspect the fuel tank (including the filler
cap), fuel pipes, hoses and unions. All
components must be secure and free from
leaks.
MExamine the exhaust system over its entire
length, checking for any damaged, broken or
missing mountings, security of the retaining
clamps and rust or corrosion.
Wheels and tyres
MExamine the sidewalls and tread area of
each tyre in turn. Check for cuts, tears, lumps,
bulges, separation of the tread, and exposure
of the ply or cord due to wear or damage.
Check that the tyre bead is correctly seated
on the wheel rim, that the valve is sound andproperly seated, and that the wheel is not
distorted or damaged.
MCheck that the tyres are of the correct size
for the vehicle, that they are of the same size
and type on each axle, and that the pressures
are correct.
MCheck the tyre tread depth. The legal
minimum at the time of writing is 1.6 mm over
at least three-quarters of the tread width.
Abnormal tread wear may indicate incorrect
front wheel alignment.
Body corrosion
MCheck the condition of the entire vehicle
structure for signs of corrosion in load-bearing
areas. (These include chassis box sections,
side sills, cross-members, pillars, and all
suspension, steering, braking system and
seat belt mountings and anchorages.) Any
corrosion which has seriously reduced the
thickness of a load-bearing area is likely to
cause the vehicle to fail. In this case
professional repairs are likely to be needed.
MDamage or corrosion which causes sharp
or otherwise dangerous edges to be exposed
will also cause the vehicle to fail.
Petrol models
MHave the engine at normal operating
temperature, and make sure that it is in good
tune (ignition system in good order, air filter
element clean, etc).
MBefore any measurements are carried out,
raise the engine speed to around 2500 rpm,
and hold it at this speed for 20 seconds. Allowthe engine speed to return to idle, and watch
for smoke emissions from the exhaust
tailpipe. If the idle speed is obviously much
too high, or if dense blue or clearly-visible
black smoke comes from the tailpipe for more
than 5 seconds, the vehicle will fail. As a rule
of thumb, blue smoke signifies oil being burnt
(engine wear) while black smoke signifies
unburnt fuel (dirty air cleaner element, or other
carburettor or fuel system fault).
MAn exhaust gas analyser capable of
measuring carbon monoxide (CO) and
hydrocarbons (HC) is now needed. If such an
instrument cannot be hired or borrowed, a
local garage may agree to perform the check
for a small fee.
CO emissions (mixture)
MAt the time of writing, the maximum CO
level at idle is 3.5% for vehicles first used after
August 1986 and 4.5% for older vehicles.
From January 1996 a much tighter limit
(around 0.5%) applies to catalyst-equipped
vehicles first used from August 1992. If the
CO level cannot be reduced far enough to
pass the test (and the fuel and ignition
systems are otherwise in good condition) then
the carburettor is badly worn, or there is some
problem in the fuel injection system or
catalytic converter (as applicable).
HC emissionsMWith the CO emissions within limits, HC
emissions must be no more than 1200 ppm
(parts per million). If the vehicle fails this test
at idle, it can be re-tested at around 2000 rpm;
if the HC level is then 1200 ppm or less, this
counts as a pass.
MExcessive HC emissions can be caused by
oil being burnt, but they are more likely to be
due to unburnt fuel.
Diesel models
MThe only emission test applicable to Diesel
engines is the measuring of exhaust smoke
density. The test involves accelerating the
engine several times to its maximum
unloaded speed.
Note: It is of the utmost importance that the
engine timing belt is in good condition before
the test is carried out.
M
Excessive smoke can be caused by a dirty
air cleaner element. Otherwise, professional
advice may be needed to find the cause.
4Checks carried out on
YOUR VEHICLE’S EXHAUST
EMISSION SYSTEM
REF