1973 OPEL GT-R heating

IIIGNITION SYSTEMlC- 19
11. (Startx position.) The ignition key must be
released as soon as engine starts. The switch then
returns aujomatically to the on position.
IGNITION
GOILThe ignition coil consists of a laminated non- mag-
netic iron
(core enclosed by two coils; the primary
winding and the secondary winding.
The prim+y circuit consists of the power source
(battery), the ignition switch, the ignition coil pri-
mary winding, the distributor breaker points with
ignition condenser connected in parallel, and all con-
necting
lo& tension wiring.
The secondary circuit consists of the ignition coil
secondary ‘winding, the spark plugs, all connecting
high tens@ wiring, the distributor cap and the
ro-tor.
When the’ ignition switch is turned on and the
breaker pdints are closed, current flows through the
ignition
c&l primary winding and produces a mag-
netic field wound the coil windings.
When the breaker points are separated by the revolv-
ing distributor cam, the magnetic field collapses and
induces a high voltage surge in the secondary wind-
ing,
produ;cing a spark between the spark plug elec-
trodes. ,
The ignitidn condenser which is connected in paral-
lel with the breaker points, prevents arcing between
the
separa’ted breaker contacts, and current flow
after~ the breaker points have been separated, thus
causing a kery rapid collapse of the magnetic field
around th$ Ignition coil.
/
IGNITION ‘DISTRIBUTORThe ignitidn distributor breaks the primary current,distributeslthe high voltage surges induced in the coil
secondary winding to the spark plugs according to
the engin< tiring order and sets ignition timing in
relation to. engine RPM and load.
The housi+g of the distributor contains the centrifu-
gal advance mechanism and the movable breaker
plate with’s breaker lever and contact support. The
vacuum advance mechanism is attached to the
breaker plate and mounted on the outside of the
distributor, housing. See Figure lC-1.
The distributor shaft is driven by a helical gear on the
camshaft and in turn drives the engine oil pump. The
ignition condenser is mounted on the outside of the
housing. The engine output is to a large extent in-
fluenced b) the ignition timing. Maximum engine
performance is obtained when the combustion proc-
ess is well underway as the piston starts down on thepower stroke. The air-fuel charges are, however, not
burned instantly, so it is necessary to advance the
spark in relation to the piston top dead center as
engine speed increases or as engine load decreases.
If the spark is too far advanced, the engine knocks,
causing a drop in engine power output and overheat-
ing. If the spark is retarded, part of the energy deve-
loped during combustion is wasted which will result
in reduced engine power output, excessive fuel con-
sumption and overheating.
The ignition distributor has a double acting double
diaphragm vacuum unit. See Figure lC-1. The ad-
vance unit is supplied with “ported” vacuum. That
is, vacuum is supplied from a port in the primary
barrel of the carburetor located just above the closed
throttle valve. This port supplies no vacuum during
idling nor during closed throttle deceleration, but
supplies full intake manifold vacuum at all speeds
where the throttle valve is opened enough to uncover
the port.
Figure lC-1 Ignition Distributor
The retard unit is supplied with intake manifold
vacuum at all times by means of a line connected
directly to the intake manifold. During idling and
deceleration, when there is no vacuum to the ad-
vance unit, the retard unit will cause the timing to be
retarded 5 degrees. However, during part throttle
operation when there is vacuum to the advance unit,
the advance unit will overpower the retard unit so
that the retard unit has no effect on timing.
The purpose of the retard unit is to reduce hydrocar-
bon and carbon monoxide emissions during idling
and deceleration, where they are especially bad.
In order to avoid voltage losses for easier starting, a
plastic cover has been inserted in the distributor be-
low the rotor as a seperator to keep the inside of the
distributor cup free from condensation.

3C-26 1973 OPEL SERVICE MANUAL
1. Loosen lock nut of left and right tie rod and
slacken back nut.
2. Remove hose clamp for rubber bellows attach-
ment from respective axial joint and adjust toe-in by
turning axial joint. When doing this, observe that the
rubber bellows, having a tight seat on thejoint, is not
twisted. If necessary, lubricate seat of bellows and
hold back bellows when turning. See Figure 3C-7.Figure
3C-7 Adjusting Toe-In Opel 1900 Manta
3. Toe-in should be l/S”
- 3/16”.
4. Torque lock nut of left and right tie rod to 47
ft.lbs.5. Attach respective rubber bellows with hose clamp,
making sure that clamp bolt points towards the
front. The rubber bellows must not be twisted, i.e.,
SpecificationsFRONT END ALIGNMENTthe individual grooves of bellows must be in vertical
position.
6. After adjustment, turn steering several times to the
left and right to determine if a proper attachment of
both rubber bellows to the steering gear housing is
warranted.
CHECKING THEORETICAL KING PIN
INCLINATION
When checking theoretical king pin inclination, car
must be on a level surface, both transversely and fore
and aft, must have trim heights within limits, and
must be at curb load.
With camber known to be within specitied limits,
theoretical king pin inclination should check to 8.5
degrees for Opel 1900
- Manta, and 6 degrees for GT.
If camber is incorrect beyond limits of adjustment
and theoretical king pin inclination is correct, or
nearly so, a bent steering knuckle is indicated.
There is no adjustment for theoretical king pin incli-
nation as this factor depends on the accuracy of the
fronts suspension parts. Distorted parts should be re-
placed with new parts.
The practice of heating and bending front suspension
parts to correct errors must be avoided as this may
produce soft spots in the metal in which fatigue and
breakage may develop in service.
MODELCASTER
’CAMBER ’TOE-INOUTER WHEEL
MIN.. MAX.WHEN INNER
WHEEL AT 20
’1900‘3
l/2-61/2-1?1/2I/% - 3/1619 l/4GT3+1
1+1/2l/32 - l/818 l/2* Permissable deviation from left to right wheel
- maximum 1”.

6A. 41973 OPEL SERVICE MANUAL
hand side above crankshaft sprocket, has a plunger
head with oil- proof and wear-resistant synthetic
rubber pad, which is pressed against chain by both
spring and oil pressure.
Figure 6A-2 Sectional View. Timing System
The top end of the short, light-weight hydrauricvalve
liffers is provided with a cup in which tits the
ball end of a stud engaged in an elongated hole in
rocker arm, thus maintaining transverse alignment
of the rocker arm.
The rocker
xrn is a steel stamping and pivots on
a ball secured by a self-locking nut on a stud screwed
into the cylinder head. This arrangement permits
easy valve clearance adjustment. All valves have oil
seals installed between valve spring and cap.
The
fuelpump is located at bottom left-hand side
of timing case and operated by, a cam integral with
distributor drive gear riveted
‘to distributor drive
shaft.
The aluminum alloy cast intake manifold with
smooth walls provide better charge of cylinders,
especially at high engine RPM. It is a four-port
manifold, i.e. there are separating walls between all
arms, one for each cylinder. An adapter for crank-
case ventilation hose leading to rocker arm cover is
arranged on front portion of intake manifold.Hot exhaust gases are used for heating a vaporization
plate located at bend of intake manifold below carbu-
retor and communicating with its tinned underside
with the interior of the exhaust manifold to ensure
that only vaporized fuel reaches the cylinders.
LUBRICATION SYSTEM AND OIL PUMPThe engine is lubricated by a forced feed system
Figure
6A-3 Oil Pump Pressure Relief Valve
Figure 6A.4 Rear Cross Sectional View

COOLING SYSTEM6B- 33
remove drain plug on right.side of cylinder block. Set
heater temperature control valve at full heat posi-
tion. After the cooling system is drained, and plugs
reinstalled, fill the system with clean water. Run the
engine long enough to open the thermostat for com-
plete circulation through the system, then com-
pletely drain the cooling system before sediment has
a chance to settle.
Conditioning the Cooling System
“Rust Inhibitor and Stop Leak”, or equivalent listed
under Group 8.800 is recommended for use in the
cooling system, particularly when preparing for in-
stallation of anti-freeze solution. This material stops
small seepage leaks, has rust preventive properties
and its soluble oil is effective in eliminating a squeal-
ing noise which sometimes develops at the water
pump seal washer. Instructions for its application are
printed on the conditioner bottle.
It is very important to make certain that the cooling
system is properly prepared before an anti-freeze so-
lution is installed, otherwise loss of solution through
leakage may occur or seepage may result in damage
to the engine. The cooling system should be drained
and flushed as described under Draining and Flush-
ing Cooling System. All joints should be checked for
leakage and corrected, and the conditioner described
above should be added with the anti-freeze solution.
Inspect the water pump, radiator core, heater and
defroster cores, water jacket plugs, and edge of cylin-
der head gaskets for evidence of water leaks. Tighten
all hose clamps in the cooling and heating systems
and replace any deteriorated hoses.
Using and Testing Anti-Freeze
Solutions
Inhibited year around (ethylene glycol type) engine
coolant solution which is formulated to withstand
two full calendar years of normal operation without
draining or adding inhibitors should be used at all
times. Freeze protection should be provided to pro-
tect against corrosion. When adding solution due to
loss of coolant for any reason or in areas where tem-
peratures lower than minus 20 degrees F. may be
encountered, a sufficient amount of any of the sev-
eral brands of year around coolant (Ethylene Glycol
base) compatible to GM Specification 1899-M avail-
able on the market should be used. Water or alcohol
base coolants are not recommended for this vehicle
at any time.
If for any reason water only is used as a coolant in
an emergency, it is extremely important that Buick
Heavy Duty Cooling System Protector and Water
Pump Lubricant or equivalent be added to the cool-
ing system as soon as possible. If any other cooling
System protector is used, be certain it is labeled toindicate that it meets General Motors Specification
GM 1894-M. It should be recognized that this is only
a temporary measure. The manufacture intends that
permanent type coolant solution be used year around
in the cooling system.
The cooling system should be completely drained
and the recommended coolant installed every two (2)years.It is advisable to test the anti-freeze solution at inter-
vals during the winter to make certain that the solu-
tion has not been weakened. Use only hydrometers
which are calibrated to read both the specific gravity
and the temperature, and have a table or other means
of converting the freezing point at various tempera-
tures of solution. Disregarding the temperature of
the solution when making the test may cause an error
as large as 30 degrees F. Care must be exercised to
use the correct float or table for the particular type
of anti-freeze being tested.
Fan Belt Adjustment or Replacement
A tight fan belt will cause rapid wear of the alterna-
tor and water pump bearings. A loose belt will slip
and wear excessively and will cause noise, engine
over-heating, and unsteady alternator output. A fan
belt which is cracked or frayed, or which is worn so
that it bottoms in the pulleys should be replaced. The
fan belt may be replaced by loosening the alternator
brace at alternator, slightly loosening the alternator
mounting bolts and moving alternator inward to pro-
vide maximum slack in the belt.
The alternator must be moved outward to adjust the
fan belt. After the generator brace and mounting
bolts are securely tightened, the fan belt tension
should be 45 lb. using Tensioner J-23600.
WARNING: Zfa
fan blade is bent or damaged in any
way, no attempt should be made to repair and reuse
the damaged part. A bent or damaged fan assembly
should always be replaced with a new
fal. assembly.
It is essential that fan assemblies remain in proper
balance and proper balance cannot be assured once
a fan assembly has been bent or damaged. A fan
assembly that is not in proper balance could fail and
fly apart during subsequent
we creating an ex-
tremely dangerous condition.
Radiator Thermostat Inspection and Test
A sticking radiator thermostat will prevent the cool-
ing system from functioning properly. If the thermo-
stat sticks in the open position, the engine will warm
up very slowly. If the thermostat sticks in the closed
position, the engine will overheat.
The thermostat may be removed for inspection and

6D. 421973 OPEL SERVICE MANUAL
EXHAUST SYSTEMS
ALL MODELS
CONTENTS
Subject
DESCRIPTION AND OPERATION: (Not Applicable)
DIAGNOSIS: (Not Applicable)
MAINTENANCE AND ADJUSTMENTS: (Not
Applicable)
MAJOR REPAIR:Page No.
Exhaust System (All Models). . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SPECIFICA’TIONS:
Torque Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . .
6D-42
6D-42
MAJOR REPAIR
EXHAUST SYSTEM (ALL MODELS)
Removal1. Remove exhaust pipe from exhaust manifold.
2. Loosen front exhaust pipe to mufller clamp and
pull exhaust pipe out of muffler.
3. Remove muffler damper rings.
4. Remove center exhaust pipe clamp. Remove rearmut&r and tail pipe(s) as an assembly. See Figure
6D-1.5. Remove front exhaust pipe clamp, and remove
front muffler and center exhaust pipe as an assembly,then remove center exhaust pipe from front mufler.
The front mufIler and center exhaust pipe are one
piece on production-built cars but are separate itemsfor service, the tail pipe of the Rallye and GT, has
a dual pipe with one resonator.
InstallationCheck rubber damper rings for muffler and tail pipe
hanger and replace as necessary.
1. Coat I.D. of rear muffler inlet neck and O.D. of
center exhaust pipe outlet (rear of pipe) with exhaust
sealer compound (several brands are currently avail-able on the market).2. Insert center exhaust pipe into rear mufIler and
tighten clamp.
3. Coat I.D. of front muffler outlet neck and O.D. of
center exhaust pipe inlet (front of pipe) with exhaust
sealer compound.4. Insert center exhaust pipe into front mufiler and
tighten clamp.
5. Install muffler and tail pipe assembly on rubber
damper rings and tighten hangers. See Figures
6D-1and
6D-2.6. Install front exhaust pipe into muffler. Do not
tighten clamp.
7. Be sure to install gasket between exhaust manifoldand exhaust pipe. Using bolts with washers, attach
the exhaust pipe to the exhaust manifold. Torque to
15 lb.ft.8. Align exhaust system and tighten all clamps.
9. Check alignment of exhaust system; make sure
that the exhaust system components have at least
3/4” clearance from the floor pan to avoid possible
overheating of the floor pan.
SPECIFICATIONS
TORQUE SPECIFICATIONSExhaust Pipe to Exhaust Manifold
- 15 lb.ft.

SA-10 1973 OPEL SERVICE MANUAL
HEATER SYSTEM
OPEL 1900 - MANTA
CONTENTS
Subject
DESCRIPTION AND OPERATION:
Heater System
. . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Function of the Heater
and Ventilation System
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DIAGNOSIS:
HeaterSystem
Trouble
Diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
ControlCable
Adjustment
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
Removal&InstallationHeaterHousing,. . . . . . . . . . . . . . . . . . . .Removal
& Installation Defroster Jets. . . . . . . . . . . . . . . . . . . . . .Removal
81 Installation Heater Control Housing . . . .
Removal
& Installation Heater Motor. . . . . . . . . . . . . . . . . . . . . . . .SPECIFICATIONS:
Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page No.
9A-10
9A-11
9A-11
PA-12
PA-12
9A-13
9A-14
9A-15
9A-16
DESCRIPTION AND OPERATIONHEATER SYSTEM
The temperature of the air entering the vehicle is
regulated by the heater valve and the blower. The
distribution of this air is controlled by the heater air
distributor housing under the instrument panel.
Moving the upper control lever from the left towards
the right opens the heater valve. This lever regulates
the flow of coolant through the heater core and
thereby increases or decreases the air temperature
proportionate to its travel. See Figure 9A-30.
Figure 9A-30 Heater Control AssemblyThe connectors for water inlet and outlet are located
on the left side of the heater core, viewed in driving
direction. The coolant flow is shown in the drawing.
See Figure 9A-3 1.
Figure
9A-31 Coolant Flow in Heater Core
Due to the separation of the inflowing and outflow-
ing water in the heater core, an even heating of the

REFRIGERANT COMPONENTS ALL MODELS96.23Figure 96-l 3 Basic Refrigerant Circuit
we get the heat-laden vapor outside, we can com-
press it with a pump. With enough pressure, we can
squeeze the heat out of “cold” vapor even in a warm
room. An ordinary.radiator will help us get rid of
heat.
By removing the heat, and making the refrigerant
into a liquid, it becomes the same as it was before, So,
we can run another pipe back into the cabinet and
return the refrigerant to the flask to be used over
again.
That is the way most mechanical refrigerators work
today. Now, let’s look at an air conditioning unit to
see how closely it resembles the refrigerator we have
just described.
Basic Air ConditionerWhen we look at an air conditioning unit, we will
always find a set of coils or a tinned radiator core
through which the air to be cooled passes. This is
known as the “evaporator” (Fig.
9B-14). It does the
same job as the flask of refrigerant we
spok.e about
earlier. The refrigerant boils in the evaporator. In
boiling, of course, the refrigerant absorbs heat and
changes into a vapor. By piping this vapor outside
the car we can bodily carry out the heat that caused
its creation.
Once we get vapor out of the evaporator, all we haveFigure 98.14 Evaporator Assembly
to do is remove the heat it contains. Since heat is the
only thing that expanded the refrigerant from a liq-
uid to a vapor in the first place, removal of that same
heat will let the vapor condense into a liquid again.
Then we can return the liquid refrigerant to the
evaporator to be used over again.
Actually, the vapor coming out of the evaporator is
very cold. We know the liquid refrigerant boils at
temperatures considerably below freezing and that
the vapors arising from it are only a shade warmer
even though they do contain quantities of heat.
Consequently, we can’t expect to remove heat from
sub- freezing vapors by “cooling” them in air tem-
peratures that usually range between 60 and 100
degrees heat refuses to
flow from a cold object
toward a warmer object.
But with a pump, we can squeeze the heat-laden
vapor into a smaller space. And, when we compress
the vapor, we also concentrate the heat it contains.
In this way, we can make the vapor hotter without
adding any heat. Then we can cool it in compara-
tively warm air.
That is the only responsibility of a compressor in an
air conditioning system (Fig.
9B-15). It is not in-
tended to be a pump just for circulating the refriger-
ant. Rather, its job is to exert pressure for two
reasons. Pressure makes the vapor hot enough to
cool off in warm air. At the same time, the compres-
sor raises the refrigerant’s pressure above the con-
densing point at the temperature of the surrounding
air so it will condense.
As the refrigerant leaves the compressor, it is still a
vapor although it is now quite hot and ready to give
up the heat that is absorbed in the evaporator. One
of the easiest ways to help refrigerant vapor dis-
charge its heat is to send it through a radiator- like
contrivance known as a condenser (Fig. 9B-16).
The condenser really is a very simple device having
no moving parts. It does exactly the same job as the
radiator in a typical steam-heating system. There,
the steam is nothing more than water vapor. In pass-
ing through the radiator, the steam gives up its heat
and condenses back into water.
The same action takes place in an air conditioning