1973 OPEL GT-R oil change

6A- 161973 OPEL SERVICE MANUALInspection of Connecting Rod Bearings and
Crankshaft JournalsRemove oil pan.
After removal of oil pan, disconnect two connecting
rods at a time from crankshaft and inspect the bear-
ings and crankpin journals. While,tuming crankshaft
it is necessary to
t&porarily reconnect the rods to
crankshaft to avoid possibility of damaging the jour-
nals through contact with loose rods.
If connecting rod bearings are chipped or scored they
should be replaced. If bearings
are in good physical
condition check for proper clearance on crankpins as
described under, checking clear$nce and selecting
replacement connecting rod beartngs.
If crankpin journals are scored or ridged, the crank-
shaft must be replaced, or reground for undersize
bearings, to insure satisfactory life of connecting rod
bearings. Slight roughness may be polished out withfine grit polishing cloth thoroughly wetted with en-
gine oil. Burrs may be honed off with a fine oil stone.
Use an outside micrometer to check crankpins for
out- of-round. If crankpins are mpre than
,002” out-
of- round, satisfactory life of new ,bearings cannot be
expected.
Checking Clearance and Selecting Replacement
Connecting Rod BearingsService bearings are furnished in standard size and
several undersizes. The clearance of connecting rod
(and crankshaft) bearings may be checked by use of
Plastigage, Type PG-1 (green), or equivalent, which
is soluble in oil.
1. Remove connecting rod cap with bearing shell.
Wipe off oil from bearing and crankpin journal, also
blow oil out of hole in crankshaft.
2. Place a piece of the plastic-type gauge material
Figure 6A-25 Checking Bearing
Cleatance WithPlastic-Type Gaugelengthwise along the bottom center of the lower bear-
ing shell (Figure 6A-25, view A), then install cap
with shell and tighten nuts to 36 lb. ft. Do not turn
crankshaft with gauge type material in bearing.
3. Remove bearing cap with bearing shell, the flat-
tened piece of gauge will be found adhering to either
the bearing shell or the crankpin. Do not remove it.
4. Using the scale printed on the envelope, measure
the flattened piece of gauge at its widest point. The
number within the graduation which closely corre-
sponds to the width of the gauge, indicates the bear-
ing clearance in thousandths of an inch. See Figure6A-25, View B.
5. The desired clearance with a new bearing is.0006”- .0025”. If bearing has been in service it is
advisable to install a new bearing if the clearance
exceeds .003”, however if bearing is in good condi-
tion and is not being checked because of bearing
noise, it is not necessary to replace the bearing.
6. After the proper size bearing has been selected,
clean off the gauge, oil thoroughly, reinstall cap with
bearing shell and tighten nuts to 36 lb. ft.
CRANKSHAFT BEARINGS AND SEALS
Replacement of Crankshaft BearingsA crankshaft bearing consists of two halves or shells
which are identical and are interchangeable in cap
and crankcase. All crankshaft bearings except the
rear main bearing are identical. The crankshaft end
thrust is taken up the rear (No. 5) main bearing.
Figure 6A-26 Engine Crankshaft Bearings
When the shells are placed in crankcase and bearing
cap, the ends extend slightly beyond the parting
sur-faces so that when cap bolts are tightened the shells
will be clamped tightly in place to insure positive

6A- 261973 OPEL SERVICE MANUAL
rear of cylinder head. Remove camshaft toward
front, supporting camshaft with one hand through
access hole and taking care not to damage bearing
surfaces. See Figure 6A-43.12345 6
I. OLD PRESSURE
4. COVER GASKET
RELIEF
~~- \SSEMBLY5. COVER 8 VALVE
ASSEMBLYVALVE I
2. TIMING CASE
6. COVER ATTACHING
3. OIL PUMP GEARS
SCREWS
123” 45Figure 6A-44 Oil Pump Components
1.CAMSHAFT
2. FRONT ACCESS HOLE
3. LATERAL ACCESS HOLE
4. CYLINDER HEAD
5. REAR ACCESS HOLEISA-43
Figure 6A-43 Removing Camshaft
Installation
1. Liberally lubricate camshaft journals and install
camshaft from front into cylinder head. Support
shaft through access hole in left side of head to pre-
vent damaging bearings.
2. Reinstall valve lifters, rocker arms and self- lock-
ing rocker arm nuts.
3. Install rear and side access plates.
4. Reinstall cylinder head.
OIL PUMP COVER AND GEARSRemoval and Installation of Oil Pump
Cover and Gears
1. Remove screws attaching oil pump cover assembly
to timing chain cover. Remove cover assembly and
slide out oil pump gears. See Figure 6A-44.
2. Wash off gears and inspect for wear, scoring, etc.
Replace any gears not found serviceable. Discard
pump covers scored by gear action. If pump housing
or distributor drive shaft bushing are worn (this is
only possible after a long service life), the timing case
together with all exchangeable pump parts have to be
discarded.In isolated cases, timing cases are installed in pro-
duction having
.008 in. oversize bores for pump gears
and shafts. Oversize bores may exist either for one or
both gears; these timing cases are identified by the
number “0.2” stamped into pump flange on left and-
/or right-hand side. Oversize replacement gears
should be selected according to Part Catalog specifi-
cations.
3. Liberally lubricate spindles and gear teeth and use
new cover gasket. Install oil pump cover.
If new gears are installed, their end clearance in a dry
pump housing should be checked with a straight
edge and a feeler gauge. The gears must not protrude
more than X04 in. over pump housing. See Figure6A-45.
FEELER
AUGESTRAIGHTIEDGE
Figure 6A-45 Checking Oil Pump Gear End Clearance

TUNE-UP
ALL MODELS
CONTENTS
Subject
DESCRIPTION AND OPERATION:
Purpose of a Tune-Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . .DIAGNOSIS: (Not Applicable)
MAINTENANCE AND ADJUSTMENTS:
EngineTune-UpMechanicalOperations. . . . . . . . . . . . . . . . . . . .
EngineTune-UpInstrumentChecks. . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR: (Not Applicable)
SPECIFICATIONS:
Tune-Uo Soecifications and Adjustments
. . . . . . . . . . . . . . . .Page No.6G-65
6G-6566-6766-68
DESCRIPTION AND OPERATION
PURPOSE OF TUNE-UP
The purpose of an engine tune-up is to restore powerand performance that may have been lost through,
loss of adjustment, wear, corrosion, or deterioration
of one or more parts or units. In the normal operat-
ion of an engine, these changes take place gradually
at quite a number of points so that it is seldom advis-able to attempt an improvement in performance by
correcting one or two items only. Time will be savedand more lasting results will be assured by following
a definite and thorough procedure of analysis and
correction of all items affecting power and perform-
ance. Because of Federal laws, limiting exhaust emis-sions, it is even more important that the engines
tune-up is done accurately, using the specifications
listed and the tune-up sticker found in each engine
compartment.
Economical, trouble free operation can better be as-sured if a complete tune-up is performed at first 4
months or
6,ooO miles of operation - then at 12
month or 12,000 mile intervals.
The parts or units which affect power and perform-
ance may be divided, into three groups (1) compres-sion, (2) ignition and (3) carburetion. The tune-up
procedure should cover these groups in the order
given. While the items affecting compression and
ignition may be handled according to individual
preference, correction of items in the carburetiongroup should not be attemplcu
ulllll all items in
compression and ignition have been satisfactorily
corrected.
MAINTENANCE AND ADJUSTMENTS
ENGINE TUNE-UP OPERATIONS
CompressionTo make sure hydrocarbon and carbon monoxide
emissions will be within limits, it is very important
that the adjustments be followed exactly.
The suggested procedure for engine tune-up is as
follows:1. Remove all spark plugs.
2. Position throttle and choke valve in full open posi-tion.
3. Connect jumper wire between distributor terminalof coil and ground on engine to avoid high tension
sparking while cranking engine.
4. Hook up starter remote control cable and turn
ignition switch to “on” position.
5. Firmly insert compression gage in spark plug port.Crank engine to obtain highest possible reading.

7A- 41973 dPEL SERVICE MANUALConditionPossible CauseCorrectionHeat-blued driven plate
and pressure plate
assembly.
1. Improper pedal1. Replace only driven plate, and
adjustment.adjust clutch pedal and cable.
Grab and chatter with
oil present on clutch
assembly.1. Oil leak.1. Correct oil leakage, clean
pressure plate in solvent, replace
driven plate and adjust pedal lash.
MAINTENANCE AND ADJUSTMENTS
CLUTCH LASH ADJUSTMENT
GTPedal lash, free pedal travel must be adjusted occa-
sionally to compensate for normal wear of the clutch
facings. As the driven plate wears thinner, pedal lash
decreases. Adjust clutch pedal free travel only with
ball stud located on right side of clutch housing if
cable length is not to be changed. To adjust pedal
lash proceed as follows:
1. Loosen lock nut on ball stud end located to the
right of the transmission on the clutch housing. Posi-
tion ball stud so that the outer end protrudes 3/4
inches out of housing and finger tighten lock nut. See
Figures
7A-1 and 7A-6.
2. Adjust ball stud, pivoting clutch release fork, to
obtain 3/4 to
l-1/4 inches pedal lash, free pedal. See
Figure 7A-6.
Opel 1900 and MantaThe clutch actuation works without clutch pedal free
travel. A readjustment of the clutch is only required
if the indicator lamp at the instrument panel lights
up.In synchronism with the gradual wear of the clutch
linings the clutch pedal travels from its basic adjust-
ment position upwards,
ie., towards driver. If the
clutch lining wear has reached such an extent that
the clutch pedal rests against switch, the indicator
lamp at the instrument panel lights up.
This is an indication that the clutch pedal position
has to be corrected to ensure proper clutch operat-
ion.
To
&~sure proper clutch operation, observe the fol-
lowing adjustment instructions.. For all adjustment
dimensions, refer to Figure 7A-7.
1. If the parking brake is provided with an indicator
lamp, the parking brake has to be disengaged, other-wise the same indicator lamp as for the clutch lights
UP.2. Carry out adjustment only with ball stud on clutch
housing whereby the distance (Item 20, Figure 7A-7)
between clutch housing contacting surface and
clutch release lever has to be adjusted in the rear to
4
l/4 inches.
Clutch Control Cable Adjustment(Only on
Installation of a New Clutch Disc or
Bowden
Control Wire)
GT1. Adjust ball stud so that outer end protrudes ap-
proximately 3/4 inches out of clutch housing.
2. Adjust distance between release lever and clutch
housing face at eye for control cable to approxi-
mately 4
l/4 inches. See Figure 7A-6. Hold cable in
this position and place E-ring two grooves ahead of
washer on rubber grommet. Clutch pedal free travel
is now between 3/4 and 1
l/4 inches and clutch
release bearing has proper clearance from pressure
plate.
Opel 1900 and Manta1. Adjust ball stud on clutch housing to basic dimen-
sion of approximately 3/4 inch. With lower end ofbowden control wire unhooked, push clutch release
lever towards the front so that the clutch release
bearing rests against clutch spring. Now, adjust ball
stud so that the dimension (Item 20, Figure
7A-7)between clutch housing contacting surface and
clutch release lever amounts in the rear to 4
l/4
inches.2. Pull reattached bowden control wire out of dash
panel so that clutch pedal rests against switch (in-
dicator lamp lights up).
3. In this position, install lockwasher at upper con-
trol wire attachment three grooves towards the front,
thereby completing control wire adjustment.

Figure 7C-1 Quadrant In Park Position -Opel 1900
and Manta7C- 381973 OPEL SERVICE MANUAL
R
- Reverse enables the vehicle to be operated in a
reverse direction.
N
- Neutral position enables the engine to be
started and operated without driving the vehicle.
D
- Drive range is used for all normal driving
conditions and maximum economy and has three
gear ratios. Downshifts are available for passing
by depressing the accelerator partially at lower
car speeds and through the “detent” at higher car
speeds.
S or 2
- Second range adds new performance for
hilly terrain. It has the same starting ratio as Drive
range, but prevents the transmission from shifting
above second gear to retain second gear for
acceleration or engine braking as desired. Second
range can be selected at any vehicle speed, but
should not be used above the speed shown m the
Owner’s Manual. This is to prevent over-speeding
the engine. The transmission will shift to second
gear immediately and remain in second until the
vehicle speed or the throttle position is changed
to obtajn first gear operation in the same manner
as in Drive range.
L or 1
- Lo range can be selected at any vehicle speed,
but should not be used above the speed shown in the
Owner’s Manual. The transmission will shift to low
(1st) gear immediately and remain in 1st gear regard-
less of vehicle speed or throttle position. This is par-
ticularly beneficial for maintaining maximum engine
braking.
PRINCIPLES OF OPERATION
Torque ConverterThe torque converter acts as a coupling to transmit
engine torque, through oil, to the transmission power
train. It also multiplies the torque from the engine
under certain conditions of input and output speed.
Figure
7C-2 Quadrant in Park Position - GT Models
The quadrant has six positions indicated in the fol-
lowing order: (Opel 1900 and Manta) P,R,N,D,S,
and L (Figure
7C-1); and (GT) P,R,N,D,2, and 1
(Figure 7C- 2).The torque converter used in the Opel three speed
automatic transmission consists of three basic ele-
ments: the pump (driving member), the turbine
(driven or output member) and the stator (reaction
member). See Figure
7C-3. The converter cover is
welded to the pump to seal all three members in an
oil tilled housing.
P
- Park position enables the transmission output
shaft to be locked
- thus preventing the vehicle
from roling either forward or backward. Because
the output shaft is mechanically locked by a
parking
paw1 anchored in the extension housing,
the park position should not be selected until the
vehicle has come to a stop. The engine may be
started in the Park position.Whenever the engine is running, the converter pump
turns at engine speed and acts as a centrifugal pump,
picking up oil at its center, adding energy, and dis-
charging the oil at its outer rim between the blades.
The shape of the converter pump shells and blades
cause the oil to leave the pump spinning in a clock-
wise direction toward the blades of the turbine. Asthere is no mechanical connection between converterpump and turbine, the oil is the only driving force
and strikes the blades of the turbine, transferring the

AUTOMATIC TRANSMISSION7c- 39
TURBINESTATOR
(DRIVEN MEMBER)fREACTION
MEMBER)CON;ERTER
COVERP;MP
(DRIVING MEMBER)
7c.3Figure
7C-3 Torque Converter Assembly
energy of the oil to the turbine. See Figure
7C-1. The
driven member, or turbine is splined to the transmis-
sion input shaft to transmit turbine torque to the
transmission gear train.
When the engine is idling, the converter pump is
being driven slowly. The energy of the oil leaving the
pump is very low, therefore there is very little torque
imparted to the turbine. For this reason, the engine
can idle and the car will have little or no tendancy
to “Creep.”
As the throttle is opened and pump speed increases,
the force of the oil leaving the pump increases and
the resultant torque is absorbed by the turbine.
After the oil has imparted its force to the turbine
member, oil leaving the turbine follows the contour
of the turbine blades so that it leaves the turbine
spinning counterclockwise. Since the turbine mem-
ber has absorbed the energy required to reverse the
direction of the oil, the turbine now has greater forceor torque than is being delivered by the engine, and
the process of torque multiplication has begun.TURBINE
PUMPTURBINE
PUMP7c4Figure
7C-4 Oil Flow Without Stator
If the counterclockwise spinning oil were allowed to
return directly to the converter pump, the oil would
strike the inner section of the pump blades in a direc-
tion that would hinder its rotation, cancelling out
any gains in torque that have been obtained. To pre-
vent this, a stator assembly is added, and is located
between the converter pump and turbine. See Figure7c-5.
The stator redirects the oil returning to the pump
member of the converter and changes its direction of
rotation to that of the pump. Since the direction of
the oil leaving the stator is not opposing the rotationof the pump, the energy or torque of the engine is
added to the oil as it passes through the
the entire cycle repeats. See Figure
7C-6.pump and
The force of the returning oil from the turbine tends
to rotate the stator in a counterclockwise direction,
the stator is mounted on a one-way or roller clutch
which allows it to turn clockwise but not counter-
clockwise. Therefore, at low turbine speeds, the re-
turning oil from the turbine striking the stator blades
in a counterclockwise direction causes the roller
clutch to “lockup,” and prevent the stator from turn-
ing.
As the turbine speed increases, the direction of the
oil leaving the turbine changes and flows against thestator blades in a clockwise direction. Since the sta-tar would now be hindering the smooth flow of re-
turning oil to the pump, the roller clutch releases,
and the stator rotates freely on its shaft. With this
condition, the stator becomes ineffective and no fur-
ther multiplication of engine torque is produced
within the converter. At this point the converter acts

7C. 841973 OPEL SERVICE MANUALConditionCause8. No starting in “R” range
(proper driving in all other
ranges).a) Reverse clutch failure.
9. Drive in selector lever
position “N”.a) Inadequate selector lever linkage.
b) Planetary gear set broken.
c) Improper adjustment of band.
Gear Change1. No l-2 upshift in “D” and “S”
(transmission remains in 1st gear
at all speeds).a) Governor valves stuck.
b) 1-2 shift valve stuck in 1st gear
position.
c) Seal rings (oil pump hub) leaky.
d) Large leak in governor pressure circuit.
e) Governor screen clogged.
2. No 2-3 upshift in “D” (trans-
mission remains in 2nd gear at all
speeds).a) 2-3 shift valve stuck.
b) Large leak in governor pressure circuit.
3. Upshifts in “D” and “S” only
at full throttle.a) Failed vacuum modulator.
b) Modulator vacuum line leaky or
interrupted.
c) Leak in any part of engine or
accessory vacuum system.
d) Detent valve or cable stuck.
4. Upshifts in “D” and “S” only
at part throttle (no detent
upshift).a) Detent pressure regulator valve stuck.
b) Detent cable broken or misadjusted.
5. Driving only in 1st gear of
“D” and “S” range (transmission
blocks in 2nd gear and “R”).a) “L” and “R” control valve stuck in
“L” or “R” position.
6. No part throttle 3-2 downshift
at low vehicle speeds.a) 3-2 downshift control valve stuck.
7. No forced downshift.a) Detent cable broken or improperly
adjusted.
b) Detent pressure regulator valve stuck.

7C-1341973 OPEL SERVICE MANUAL
Figure 7C-232
Torque Converter4. Rotate converter to check for free movement.
1. Place transmission on portable jack
2. Slide torque converter over stator shaft and input
shaft.3. Be sure that converter pump hub keyway is seated
into oil pump drive lugs and the distance “A” is
.20”to
.28”. See Figure 7C-232.
SPECIFICATIONS
GENERAL SPECIFICATIONS
Opel Three-Speed Automatic Transmission Fluid
RecommendationsUse DEXRON Automatic Transmission Fluid on/y
in all 1972 model Opel Automatic Transmissions
(GM part No. 1050568-69-70 or any other fluid hav-
ing DEXRON identifications).DEXIRON is an especially formulated automatic
transmission fluid designed to improve transmission
operation.
The oil pan should be drained and the strainer re-
placed every
24,ooO miles and fresh fluid added to
obtain the proper level on the dipstick. See subpara-
graph 2 for proper refill procedures. For cars sub-
jected to heavy city
traff%z during hot weather, or in
commercial use, when the engine is regularly idled
for long periods, the oil pan should be drained and
the strainer replaced every
12,ooO miles.
.
1.Checking and Adding FluidThe Opel three-speed automatic is designed to oper-
ate at the full mark on the dipstick at normal operat-
ing temperature (180 degrees F.) and should be
checked under these conditions. The normal operat-
ing temperature is obtained only after at least 15
miles of highway type driving or the equivalent of
city driving.
Fluid level should be checked at every engine oil
change.
The “FuIl” and “Add” marks on the trans-
mission dipstick indicate one (1)pint
difference. Todetermine proper fluid level, proceed as follows:
To determine proper level, proceed as follows:
1. With manual control lever in Park position start
engine. DO NOT RACE ENGINE. Move manual
control lever through each range.
2. Immediately check fluid level with selector lever
in Park, engine running, and vehicle on LEVEL
surface.At
t,his point, when a reading is made, fluid level on
the dipstick should be at the “FULL” mark.
3. If additional fluid is required, add fluid to the
“FULL” mark on the dipstick.
If the vehicle cannot be driven sufficiently to bring
the transmission to operating temperature and it