1973 OPEL GT-R Service Manual

Figure 5C-53 Rear Brake Assembly
10. Check all backing plate attaching bolts to make
sure they are tight. Using line emery cloth, clean all
rust and dirt from shoe contact surfaces on plate. See
Figure Z-53.
Relining Brake ShoesIf old brake shoes are to be relined, inspect shoes for
distortion and for looseness between the rim and
web; these are causes for discarding any shoe. If
shoes are serviceable, be governed by the following
points in installing new linings:
1. Remove old rivets by drilling them out. Punching
out rivets will cause distortion of shoe rim. Care5C- 301973 OPEL SERVICE MANUAL
must also be taken to support shoes properly while
drilling.
2. Thoroughly clean brake shoes and remove all
burrs around rivet holes.
3. Use Opel brake lining or equivalent. Install in
place and rivet in sequence shown in Figure
Z-54.Keep hands clean while handling brake lining. Do
not permit oil or grease to come in contact with
lining.
Installation and Adjustment
1. If any hydraulic conne&tions were disturbed, bleed
hydraulic system. If new parts were installed in
brake system, flushing of hydraulic system is recom-
mended.
2. Adjust rear wheel brakes.
3. Adjust parking brake.
4. Check fluid level in master cyliner and add fluid
if necessary.
5. Check brake pedal for proper feel and for proper
return.
6. Remove jacks and road test car for proper brake
action. Brakes must not be severely applied immedi-
ately after installation of new brake shoes or linings.
Severe application may perinanently injure new lin-
ings and may score brake drums. When linings are
new, they must be given moderate use for several
days until burnished.
INSPECTING AND RECONDITIONING
BRAKE DRUMSWhenever brake drums are removed, they should
bethoroughly cleaned and inspected for cracks, scores,
deep groves, and out-of-round. Any of these condi-
tions must be corrected since they can impair the
efficiency of brake operation and also can cause
premature failure of other parts.
Cracked, Scored or Grooved DrumA cracked drum is unsafe for further service and
must be replaced. Welding a cracked drum is not
recommended.
Smooth up any slight scores by polishing with tine
emery cloth. Heavy or extensive scoring will cause
excessive brake lining wear and it will be necessary
to rebore in order to true up the braking surface.
Figure 5C.54 Brake Lining Riveting
SequenceIf the brake linings are slightly worn and drum is
grooved, the drum should be rebored just enough to

DRUM BRAKES5c- 31
remove grooves, and the ridges in the lining should
be lightly removed with a lining grinder.
If brake linings are more than half worn, but do not
need replacement, the drum should be polished with
fine emery cloth but should not be rebored. At this
stage, eliminating the grooves in drum and smooth-
ing the ridges on lining would necessitate removal of
too much metal and lining, while if left alone, the
grooves and ridges match and satisfactory service
can be obtained.
If brake linings are to be replaced, a grooved drum
should be rebored for use with oversize linings. A
grooved drum, if used with new lining, will not only
wear the lining but will make it
diff%xlt, if not im-
possible, to obtain etXcient brake performance.
Out-of-Round DrumAn out-of-round drum makes accurate brake shoe
adjustment impossible and is likely to cause excessive
wear of other parts of brake mechanism due to its
eccentric action. An out-of-round drum can also
cause brake pulsation. Maximum permissible drumrunout is 004”. A drum that has more run-out than
this should be rebored. Runout can be accurately
checked by using an inside micrometer fitted with
proper extension rods.
When measuring a drum for run-out, take measure-
ments at open and closed edges of machined surface
and at right angles to each other.
Turning Brake DrumsIf a brake drum is to be turned, enough metal should
be removed to obtain a true, smooth braking surface.
Measure brake drum diameter; standard drum inner
diameter is 9.060”. Drums may be turned to an over-
size of ,030”. If maximum inner diameter after turn-
ing exceeds 9.090”, brake drum will have to be
replaced. Removal of more metal will affect dissipa-
tion of heat and may cause distortion of the drum.
1. Remove rear wheels and drums.
2. Mount brake drum on brake drum lathe and turn
drums as necessary, within limits.
3. After turning, check drum diameter. Inner diame-
ter not to exceed 9.090.
4. A newly-bored drum should always have center
contact with brake shoes. For this reason, arc grind
linings to
.OlO” under drum radius, or to ,020” under
drum diameter.
5. Clean and install drums and wheels.
BRAKE WHEEL CYLINDER OVERHAUL1. Remove wheel, drum, and brake shoes. Be careful
not to get grease or dirt on brake lining.
2. Disconnect brake pipe or hose from wheel cylinder
and cover opening with tape to prevent entrance of
dirt. Remove wheel cylinder from backing plate.
3. Remove boots, pistons, cups, and spring from cyl-
inder. Remove bleeder valve.
4. Discard rubber boots and piston cups. Thoroughly
clean all other parts with hydraulic brake fluid orDeclene. Do not use anti-freeze, alcohol, gasoline,
kerosene, or any other cleaning fluid that might con-
tain even a trace of mineral oil.
5. Inspect pistons and cylinder bore for scores, scrat-
ches, or corrosion. Light scratches may be polished
with crocus cloth. Do not use emery cloth or sandpa-
per.
Shght corro~on may be cleaned wth tine steel
wool. If scratches or corroded spots are too deep to
be polished satisfactorily, the cylinder should be re-
placed since honing is not recommended.
6. Dip internal parts in brake fluid and reassembly
wheel cylinder. When installing piston cups, use care
to avoid damaging the edges.
7. If the rear wheel backing plate is removed: Always
install new paper gaskets one on each side
- on the
backing plate. Prior to installation, lightly coat paper
gaskets with chassis lubricant. Torque backing plate
to rear axle housing bolts to 43
lb.ft. and wheel brake
cylinder to backing plate bolts to 5
lb.ft. Install wheel
cylinder on brake backing plate and connect brake
pipe or hose.
8. Install brake shoes, drum, and wheel, then flush
and bleed hydraulic system.
9. Adjust brakes, then road test car for brake per-
formance.
CAUTION:This brake backing plate to rear axle fis-
tener is an important attaching part in that it could
affect the performance of vital components and sys-
tems, and/or could result in major repair expense. It
must be replaced with one of the same part number
or with an equivalent part, if replacement becomes
necessary. Do not
use a replacement part of lesser
quahty or substitute design. Torque v&es must be
used as specified during reassembly to assure proper
retention of this part.
REPLACING BRAKE PIPESAny brake pipe assembly which is needed must be
made up from service bulk tubing and fittings. All
brake pipes must be made of tin or copper coated
wrapped steel tubing with the ends double lap flared.

5C- 321973 OPEL SERVICE MANUAL
Never use copper tubing because copper is subject to
fatigue cracking which would result in brake failure.2. Cut tubing to length. The correct length may be
determined by measuring the old pipe using a cord
and adding l/8” for each double lap flare.
To make up a brake pipe assembly, proceed as fol-
lows:3. Double lap flare tubing ends, using a suitable flar-
ing tool such as J-8051. Follow the instructions in-
cluded in the tool set. Make sure fittings are installed
1. Procure the recommended tubing and fittings of
the correct size. (Outside diameter of tubing is used
to specify size.)before starting second flare.
4. Bend pipe assembly to match old pipe.
SPECIFICATIONS
BRAKE SPECIFICATIONS
Torque Specifications
Use a reliable torque wrench to tighten the parts listed to insure proper
tightness without straining or distorting parts. These specifications are for
clean and lightly-lubricated threads only; dry or dirty threads produce in-
creased friction which prevents
accurage measurement of tightness.
PartName
TorqueNut
BoltBrakeHose to Front WheelBrake Cylinder
Brake Backing Plate to Steering Knuckle(Uccer
Bolts)Lb&.
22
22...BoltBrake Backing’Plate to Steering Knuckle and
SteeringArm(Lower
Bolts)............................................
BoltBackingPlatetoRearAxleHousing................................
NutMaster Cylinder Actuator Rod to BrakePedal
..............
BoltWheelBrake Cylinder to Brake Backing Plate
..............
General Specifications47
43
5
5OperatingMechanism,ServiceBrakes
....................................................................Hydraulic
Parking Brakes
..........................................................................................Lever and Cables
Operation of Service Brakes Independent of
ParkingBrakes
..................................................................................................................Yes
WheelBrakes,Service
......................................................................................FrontandRear
Parking.
..................................................................................................................Rear Only
BrakePedalHeightAdjustment......................................................................................None
Static Pressure in Hydraulic System When Brakes
are Released
- Drum Brakes................................................................................4 psi Min.
Static Pressure in Hydraulic System to Rear
BrakesOnly
-DiscBrakes..................................................................................
4psiMin.
Brake Master Cylinder (for Drum Brakes) Bore
............................................................13/16
Wheel Cylinder Size
- Rear - All.......................................................................................: 5/8
Approved Hydraulic Brake ,Fluid
..........................................GM or Delco Supreme No. 11
Fluid Level in Reservoir
..........................................................................Fill to “Max.” Level
BrakeDrumRebore,Max&urnAllowable Inside
Diameter........................................
9.090Max. Allowable Out-of-Round
...........................................................................................CKl4Rear Brake Drum Size. New
............................................................................................
9.060

GROUP 6
ENGINESection6A
6B
6C
6D
-
6E
6F6GTitle
‘age No.
EngineMechanical and Mounts
AllModels
Cooling System
AllModels
. . . . . . . . . . . . . . . . . . . . . .
Fuel SystemAll
Models. . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Systems
AllModels
. . . . . . . . . . . . . . . . . . . . . . . .
Carburetor
And
ThrottleLinkage
. . . . . . . . . . . . . .
Emission Control
Systems
- All Models . . . . .6A- 2
6B-326C-366D-42
6E-446F-60
Tune-Up
AllModels
. . . . . . . . . . . . . . . . ..__....66-65

6A- 21973 OPEL SERVICE MANUAL
ENGINE
CONTENTS
Subject
DESCRIPTION AND OPERATION:
EngineConstruction..........................................................
LubricationSystem............................................................
DIAGNOSIS:
Excessive Oil Consumption............................................NoisyValvesandLifters..................................................
MAINTENANCE AND ADJUSTMENTS:
Valve
LifterAdjustment..................................................
MAJOR REPAIR:
Engine Removal and Installation..................................
Engine
OilPanRemoval
andInstallation..................
Manifold, Cylinder Head, Valve Train and
Lifters................................................................................
Connecting Rod Bearings................................................
Crankshaft Bearings and Seals....................................
Piston, Rings and Connecting Rods............................
TimingChainCoverandTimingChain......................
Camshaft..............................................................................
Oil Pump Cover and Gears............................................
SPECIFICATIONS:
BoltTorque.Specifications
..............................................General Specifications......................................................
Engine Dimension and Fits............................................Page No.
6A- 2
6A- 4
6A- 6
6A- 6
6A- 7
6A- 86A-106A-126A-156A-166A-196A-236A-256A-266A-276A-286A-29
DESCRIPTION AND OPERATION
ENGINE CONSTRUCTION
Engine UsageThe 1.9 liter engine is standard equipment on all 1973
Opel
1900, Manta and GT models. This engine has
a compression ratio of
7.6:1 and operates on“regular” low lead grade fuel.
Engine ConstructionThe
cyfinderhead is made of high-grade chromium
grey cast iron. The valve guides are cast intergal with
the head. The overhead camshaft is supported in four
bearings in the cylinder head.Location of the
vzllve seats in combustion chamber
is above the center of cylinder bore. The spark plug
is positioned in the center and near the highest point
of combustion chamber. This arrangement provides
for short flame travel, uniform combustion and good
cold start prop&ties. Exhaust valves have seat in-serts of highly heat and water resisting material. The
head surface is alumetized and so are the seats of the
inlet v&es Alumetizing makes the valve heads
non- scaling and promotes long life. All engines have“rota-caps”.
The forged, five main bearing crankshaft has large-
diameter main and connecting rod bearing journals
with considerable overlap for vibration-free operat-
ion. T&metal bearing shells are used for main and
connecting rod bearings. The crankshaft end play is
controlled by the rear main bearing.

ENGINE MECHANICAL AND MOUNTS6A- 3
Figure 6A-1 Side Cross Section View of Engine
This engine has full skirt “Autothermic” type pistons
with two horizontal slots in oil control ring groove,
which partly separate head and skirt to maintain
good contact with the cylinder walls throughout the
entire temperature range.
The camshaft located in the cylinder head is an
important design feature of the new power units.
This arrangement permits an extremely rigid valve
train which accounts for precise valve timing. Thegray cast iron camshaft has induction hardened bear-
ing journals and cams. Installation of camshaft is
facilated by each diameter of the four bearings and
journals being slightly smaller than the preceding.
Camshaft end play is controlled at forward end bythe camshaft front bearing seat outer face in one
direction, and by the front bearing cover in the other
direction. A nylon bolt in camshaft forward end
serves to adjust end clearance.
The camshaft is driven by an endless Duplex
rollerchain. The crankshaft double sprocket and pulley
arc held by one key. The camshaft sprocket is fixed
with a guide pin and attached with 3 bolts.
Inside the timing case, a long damper block is prov-
ided on the driving side of the chain and a shorter,
curved spring plate tensioner on the non-driving
side. Both have wear-resistant and oil-proof
sny-thetic rubber slipper pads. The self adjusting chain
tensioner located on driving side of chain at right

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

ENGINE MECHANICAL AND MOUNTS6A- 5
incorporating a gear-type pump driven by the dis-
tributor shaft. The pump body forms part of the
timing case. A passage cast in cylinder block and a
suction pipe connect the pump to the screen cover
assembly in the sump of the oil pan.
The oil pump pressure relief valve is located in the
engine oil pump cover. See Figure 6A-3. The pres-
sure relief valve serves to feed surplus oil back into
the suction passage should the required oil pressure
be exceeded. The old oil pressure relief valve which
is located above the oil filter is inoperative. A heavier
spring has been installed to keep the valve seated at
all times.
The oil filter is of the full flow type. With it in paral-
lel is a by-pass system controlled by a valve in the
timing chain cover above the oil filter which ensures
oil circulation directly to lubrication points if ele-
ment becomes clogged by dirt or oil is too thick to
pass through. Only when oil flow through element is
unrestricted the by-pass valve will close and filtered
oil is fed to the engine.
Oil flow through the engine is as follows: The oil
pump draws oil from the sump through the screenand pumps it through drilled passages in timing case
to the full flow filter. From there it passes to the
cylinder block main oil gallery with a branch in tim-
ing case to no. 1 camshaft bearing. Drilled passages
lead from the oil gallery to crankshaft main bearings
and in the crankshaft from main bearings to connect-
ing rod bearings. The camshaft front journal has a
crescent shaped groove which controls the oil supply
to cylinder head oil gallery. The cylinder head oil
gallery delivers oil under pressure to all valve lifters,
to Nos. 2, 3 and 4 camshaft bearings, and to rocker
arm seats. An additionally drilled passage connects
the valve lifter circular groove with circular groove
of rocker arm stud from where the oil is directed
upwards through a drilled passage to the rocker arm
seat. The cams are lubricated by oil under pressure.
Surplus oil collects at end of cylinder head and re-
turns through a passage to the crankcase. A cali-
brated squirt hole in connecting rod big end bearing
sprays oil against right-hand side of cylinder wall:
Additional cylinder wall and piston pin lubrication
is through oil splash from crankshaft. A jet in timing
case projects oil against oil pump drive, and the tim-
ing chain receives lubrication from above the chain
tensioner.
Figure 6A-5 Engine Lubrication System