1973 OPEL GT-R engine

5C- 281973 OPEL SERVICE MANUAL
Figure 5C-51 Rear Wheel Brake Adjustment
disconnected, or when cables have been stretched
through extended use. Need for parking brake ad-
justment is indicated if the service brake operates
with good reserve, but the parking brake handle
can be engaged, more than eight ratchet clicks
under heavy pressure.
After making certain that service brakes are in good
adjustment, adjust parking brake mechanism as fol-lows:1. Fully release parking brake lever; check parking
brake cable for free movement.
2. Loosen equalizer nut or adjusting nut, depending
upon whether. tension is to be increased or decreased
on cable.
3. Pull parking brake lever up by three (3) clicks. In
this position, adjust equalizer with adjusting and
lock nuts so that rear brakes just begin to bind. Take
care that rear brake action is equal on both rear
wheels. In case of unequal brake action, apply lubri-
cant to equalizer and brake cable.
4. After adjustment, tighten lock nut. Be certain that
equalizer is in horizontal position. Check operation
of parking brake. If parking brake adjustment doesnot result in proper brake action, inspect linings on
both rear wheels for possible replacement.
Filling Brake Master Cylinder
ReservoirThe master cylinder reservoir must be kept properly
filled to insure adequate reserve and to prevent air
from entering the hydraulic system. However, be-
cause of expansion due to heat absorbed from brakff
and from engine, master cylinder must not be over-
tilled.
The plastic brake fluid reservoir is attached to the
master cylinder which is located under the hood on
the left side of the cowl.
Thoroughly clean reservoir cover before removal to
avoid getting dirt into reservoir. Remove cover and
add fluid as required to bring level up to “MAX.”
marked on reservoir.
Use Delco Supreme No. 11 Hydraulic Brake Fluid
or equivalent.
Do not use shock absorber fluid or any other fluid
which contains mineral oil. Do not use a container
which has been used for mineral oil. Even a trace of
mineral oil will cause swelling and distortion of rub-
ber parts in the hyrdaulic brake system.
Bleeding Brake Hydraulic SystemA bleeding operation is necessary to remove air whe-
never it is introduced into the hydraulic brake sys-
tem. Since air is compressible and hydraulic fluid is
not, the presence of air in the system is indicated by
a springy, spongy feeling of the brake pedal accom-
panied by poor braking action.
Air will be introduced into the hydraulic system if
the brake pedal is operated when the fluid is too low
in master cylinder reservoir. Air will also enter the
system whenever any part of hydraulic system is
disconnected.
It will be necessary to bleed both hydraulic systems
if air has been introduced through low fluid level or
by disconnecting brake pipes at master cylinder. If
brake pipe is disconnected at any wheel cylinder,
then that wheel cylinder only need be bled. If pipes
are disconnected at any fitting located between mas-
ter cylinder and wheel cylinders, then the wheel
cylinder(s) served by the disconnected pipe must be
bled.
Sequence for Bleeding Wheel
Cylinders or CalipersIt is advisable to bleed one wheel cylinder or caliper

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

6A. 61973 OPEL SERVICE MANUALDIAGNOSIS
EXCESSIVE OIL CONSUMPTION
ConditionCorrectionExternal Oil Leaks at:Tighten attaching bolts. If leaks
Rocker Arm Coverspersist, remove cover (or pan),
Crankcase Front Covercheck sealing surfaces for burrs
Oil Pan and Gasketor scoring, replace gasket, and
seal bolts with silastic sealer or
equivalent. Make sure oil level
,is not overfull.
Improper Reading of Dip-Car may not be level when taking r
StickInsuffIcient oil “drain-back” time
after stopping engine (three
minutes must be allowed). Dip-
stick may not be completely pushed
down against stop. Dipstick may
be bent.
Oil Viscosity Too LightUse recommended SAE viscosity for
prevailing temperatures.
Continuous High-SpeedAt speeds above 60 mph, increased
Drivingsumption can be expected with any
Inform customer of this fact.
High-Speed DrivingWhen principal use of automobile i
Following Normal Slowcity driving, crankcase dilution f
Speed City Drivingcondensation occurs. High speed a
temperatures will remove water,
resulting in what appears to be
rapid lowering of oil level.
Inform customer of this fact.
Piston Rings NotAllow engine to accumulate at leas
“Broken In”
4,OCO miles before attempting any
engine disassembly to correct for
oil consumption.
NOISY VALVES AND LIFTERSIf the preceding check indicates valve mechanism is
abnormally noisy, remove the rocker arm cover so
that the various conditions that cause noise may be
The noise level of the valve mechanism cannot bechecked. A piece of heater hose of convenient length
properly judged where the engine is below operatingmay be used to pick out the particular valves or valve
temperature when the hood is raised, or when thelinkages
thit are causing abnormal noise. With the
valve rocker arm covers are removed.engine running at a speed where the noise is pro-
nounced; hold the end of hose to an ear and hold
Before attempting to judge valve noise level, the en-other end about
l/2 inch from point of contact be-
gine must be thoroughly warmed up (at least 20tween rocker arm and valve stem. Mark or record the
minutes of operation at
1200 to 1500 RPM) to stabil-noisy valves for investigation of following causes:ize oil and coolant temperatures and bring all engine
parts to a normal state of expansion. When the
en-1. Sticking, Warped, or Eccentric Valves, Worngine is warmed up, listen for engine noise while
sit-Guides Sticking valves will cause irregular engine
ting in the driver’s seat with the hood closed. Run theoperation or missing on a low speed pull and will
engine at idle and at various higher speeds.usually cause intermittent noise.

ENGINE MECHANICAL AND MOUNTS6A- 7
Pour penetrating oil over the valve spring cap andengine off. It makes no difference whether the engine
allow it to drain down the valve stem. Apply pressureis cold or is at operating temperature. Set piston of
to the one side of the valve spring and then the other,the respective cylinder to upper top center on the
and then rotate the valve spring about l/2 turn. Iffiring stroke. This can be accomplished by removing
these operations affect the valve noise, it may bethe distributor cap and observing the rotor. Check
assumed that valves should be reconditioned.position of the rotor and follow spark path for the
2.Worn or Scored Parts in the Valve Train Inspectrotor tip through the distributor cap, high tension
rocker arms, push rod ends for scoring. Check pushwire to spark plug. This determines which cylinder
rods for bends, valve lifters, and camshaft surfacesis at upper top center on the firing stroke. Adjust the
for scoring. Replace faulty parts.hydraulic lifters of the two valves for that cylinder at
this time. When they are adjusted, turn engine so
MAINTENANCE AND ADJUSTMENTSthat another.cylinder is at upper top center on the
firing stroke and adjust the two valve lifters for that
VALVE LIFTER ADJUSTMENTcylinder. Repeat process until all valves are adjusted.
See Figure 6A-6 for correct rotor position for each
Perform hydraulic valve lifter adjustment with thecylinder.
CORRECT ROTOR POSITION TO ADJUSTCORRECT ROTOR POSITION TO ADJUST
VALVES ON CYLINDER NO. 1VALVES ON CYLINDER NO. II
CORRECT ROTOR POSITION TO ADJUSTCORRECT ROTOR POSITION TO ADJUST
VALVES
ON CYLINDER NO. IllVALVES ON CYLINDER NO. ,VW-6Figure
6A-6 Rotor Positions for Valve Lifter Adjustment