1973 OPEL GT-R service

lC- 22 1973 OPEL SERVICE MANUAL j
3. Start engine and disconnect a wire from a spark
plug. Read output voltage of disconnected spark
plug circuit. Reading should exceed 20 KV
(20,poO
volts).I
CHECK DISTRIBUTOR
!1. Clean distributor cap and inspect it for cracks or
tracking. Inspect inner segments for erosion and
outer sockets for corrosion.
2. Clean and inspect ignition wires. Make sure resist-
ance of each wire is less than 10,000 ohms. Replace
any defective spark plug boots or distributor
capnipples. See paragraph lC-12.
3. Inspect breaker points and replace if necessary.
Adjust breaker point gap to
,016 inch with rubbing
block on peak of cam lobe or check dwell and adjust
if not 50 degrees plus or minus 3 degrees. 4. Check
dwell variation by reading dwell at idle and at 3000
RPM. Dwell must not vary more than 3 degrees.
Excessive variation means distributor shaft, cam or
breaker plate are worn or damaged--overhaul dis-
tributor and replace defective parts.
5. Check distributor condenser for a minimum series
resistance and insulation leakage. Check for a
capacity between
.15 and .20 microfarads.
6. Check total advance (centrifugal and vacuum) at
2500 engine RPM using a timing light having a dial
for reading advance.
(a) The timing marks are aligned with both the
vacuum advance and the vacuum retard hoses dis-
connected and plugged.
Engine idle should be 900 RPM.
(b) Reconnect vacuum hoses. Run engine at
3600RPM and adjust knob until timing marks are
aligned. Read advance on dial. Maximum centrifugal
advance should be between 28-32 degrees.
7. If total advance is out of specifications, check
centrifugal advance only, at
2500 RPM. Discon+ectand plug all vacuum hoses. Maximum vacuum ad-
vance should be l-5 degrees at 4.5-5.0 in. hg.
8. Replace centrifugal or vacuum advance parts as
required to bring distributor total advance within
specifications.
9. Check operation of vacuum retard unit (rear unit)
by first making sure timing marks are aligned with
vacuum hoses disconnected and at slow idle (700
RPM). Then connect vacuum hose to vacuum retard
unit (rear unit). Timing ball should move in a retard
direction (upward).
CHEICK SPARK PLUGS1. Remove spark plugs. If electrodes are badly worn,
discard plugs. If inner or outer porcelain is cracked
or broken, discard plugs.
2. Note color and general appearance of inner end of
spark plug. Brown to grayish
- tan deposits and slight
electrode wear indicate correct spark plug heat
range. Plugs having this appearance may be cleaned,
regapped, tested and reinstalled.
3. Clean spark plugs in a sand blast type cleaner.
Clean only enough to remove deposits, not enough to
wear away porcelain. If deposits are too hard to
remove or if porcelain is glazed, discard plugs.
4. After cleaning spark plugs, clean tiring surfaces of
electrodes with a line file.
5. Test cleaned spark plugs on a pressure tester by
comparing spark of the used plugs with that of a new
plug. Install tested plugs, using new gaskets.
6. If removed spark plugs have excessive carbon foul-
ing and if the car will be driven mostly at low speeds
in city driving, it is advisable to replace plugs with
a hotter plug, AC43FS.
7. If removed plugs show rapid electrode wear or
inner porcelain breakage at low mileage. Check for
a vacuum leak such as a poor manifold to head fit.
8.
Clap spark plugs carefully (new or cleaned) using
a
,030 round wire feeler gage.IC6
Figure lC-6 Distributor Installation

lC- 261973 OPEL SERVICE MANUAL /
SPECIFICATIONSIGNITION COIL
Ignition Coil Number
.,.:.................................................................................................K12 V
Ignition Coil Current Draw, Amperes at 12.5 Volts
EngineStopped
...........:.........................._............................................................................3.8Engine Idling
....................................................................................................................2.3
DISTRIBUTORDistributor TypeNumber:
..................................................................................................JFU4
Total Advance (Centrifugal and Vacuum), Engine Degrees at 3600 R.P.M.
EngineRPM
..................................................................................................................29-37Centrifugal Advance, Engine Degrees and RPM
StartAdvance,atRPM
........................................................................................lOOO-1200MediumAdvance,DegreesatRPM
..............................................................7.5-15at1400Maximum Advance, Dkgrees at RPM
..........................................................28-32 at 3600
Vacuum Advance, Engine Degrees and
In. of Vacuum
Start Advance, at In. of Vacuum
................................................................-5 at 2.9-4.1 In.
Maximum Advance, Degrees at In. of Vacuum
........................................l-5 at 4.5-5.0 In.
VacuumRetard,EngineDegreesatClosedThrottle
............................................................-5CondenserCapacityinMicroFarads
...............................................................................15-.20Breaker Spring Tension in Ounces
..............................................................................14 to 19
Breaker Point Gap in Inches
..............................................................................................,016Dwell angle in Engine Degrees
....................................................................................50 + 3
Firing Order
....................................................................................................................l-32-2
SparkPlug or CoilCable,Max.Resistancti in Ohms
..................................................10,ooO
SPARK PLUGSMake and Model
-Production................I....................................................................AC42FS
Make and Model
- Replacement...................................................................................AC42FS
Ifcarbonfouling
occurs,use.....................................................................................AC43FS
SparkPlugTorqueinLb:Ft.
............................................................................................22-29Spark Plug Gap in Inches
...........................................................................................028-.03 1

i
1 D- 301973 OPEL SERVICE MANUAL
6. Make sure all electrical accessories are turned (lff.
Start engine with battery post adapter switch closed;
open switch as soon as engine
iS: started.
7. Adjust engine speed to 2500 RPM.
8. Turn tester control knob to “LOAD” position
aid
adjust knob to obtain highest possible ammeter r&d-
ing. Output must be 30 amperes minimum. If
outcut
is okay, proceed to voltage regulator test below. j
/.9. If output is low, defect may be in alternator or m
regulator. To eliminate regulator, supply field &-
rent direct to cause full alternat,or output. Unplug
three-way connector from regulator and plug in a
jumper between the red and black leads. See Figure
lD-5. Retest as described in Steps 7 and 8. If output
is still low, generator is faulty and must be
remov&d.
301D5 :
Figure lD-5 Alternator Ouiput Check I
10. If output (using field jumper) is now okay, defect
is in the regulator or wiring harness. Check all wiring
connections. If all wiring is okay, try
replac/~g
regulator; if output now tests okay (without
uslpg
field jumper), you have found the trouble. Always
follow-up with a voltage regulator test.
Test and Adjust Voltage Regulator Setting
1. Always test alternator output first, as describedlin
subparagraph a above. Leave all test
instrumeqts
connected, but make sure field
jumper is removed; if
used.
2. With engine speed at 2500 RPM, turn tester con-
trol
knob to “l/4 OHM” position. Make sure ill
electrical accessories are turned off. After volt&e
reading stabilizes, any reading between 13.5 and 14.5
volts is okay.
3. If voltage reading is out of limits, remove regulator cover and adjust voltage regulator armature spring
tension to obtain a middle reading of 14.0 volts. If
reading fluctuates, voltage contacts are dirty.
4. Replace regulator cover and recheck voltage set- ting. A steady voltage reading between 13.5 and 14.5
volts means voltage regulator is okay.
5. Adjust engine speed to specified idle. Reseal volt-
age regulator cover carefully, using electrical tape.
MAJOR REPAIR
ALTERNATOR OVERHAUL
Always disconnect battery ground cable before mak-
ing any electrical repairs.
Alternator Removal
1. Disconnect battery ground strap.
2. Unplug wiring connector from alternator. 3. Disconnect battery lead from alternator.
4. Remove adjusting brace bolt, lockwasher, plain
washer and nut.
5. Loosen pivot bolt. Push alternator inward and
remove belt from pulley.
6. Drop alternator down and remove pivot bolt, nut,
lockwasher and plain washer.
7. Remove alternator.
Figure 1D-6 Removing Alternator Pulley

1 D- 32 1973 OPEL SERVICE MANUAL
12. Unsolder brushes, if they are worn to a length of
3/8 inch or less. Solder new brushes in place. To do
this, hold connecting wire in flat-nosed pliers to
pre:
vent
solder from flowing between wire strands, oth-
erwise the wire strands will become rigid and the
brushes unserviceable. See Figure
lD-15.
Figure 1D-12 Disconnecting Brush Connector
Figure 1 D-l 5 Soldering New Brushes
Note brush wire installation of correct assembly. See
Figwe lD- 16.
Figure 60.13 Removing Biush Holder
9. Unsolder diode connections and stator winding
ends. Clamp pliers on wire to transfer heat away
from diodes. Unsolder quickly using a very hot sol-
dering iron, as the diodes are very sensitive to heat.
See Figure
lD-14.
Figure 1 D-l 6 Brush Wire Installation
Figure 1 D-l 4 Unsoldering Connections
10. Remove stator assembly from housing.
Il. Remove two screws and negative diode support. 13. Test rotor windings and slip rings for a ground,
using a test light or an ohmmeter. Test light should
not light; ohmmeter should read near infinite resist-
ance end of scale. See Figure
lD-17.
14. Test rotor windings for a short by connecting an
ohmmeter between the two slip rings. Ohmmeter
should read between 4.0 and 4.4 ohms. See Figure
lD- 18.
15.
Test stator windings for a ground, using a test
light or an ohmmeter. Test light should not light;
ohmmeter should read near infinite resistance end of
scale. See Figure
lD-19.

1 D- 34 1973 OPEL SERVICE MANUAL!
I
one direction, but should not light at all in the otlier
direction. Diodes in each set of three should p&s
current and block current in the ‘same directions
Asthe others in the set. See Figure lD-21.
Removing Diodes/
Positive Diodes1. Press defective diode out of diode support, back-
ing-up support with a sleeve sliglitly larger than the
diode and pushing diode through with a shaft
slightly smaller than diode. See Figure lD-22.;
Figure 1 D-22 Removing Diode
Negative Diodes1. Clip lead from defective diode. Clip lead close
enough to diode so that tool will .function properly.
Figure 1 D-d3 Removing Diode2. Using Tool J-23526, press diode from support. See
Figure lD-23.
Installing Diodes
Positive Diodes1. Press new diode into diode support. See FigurelD-24.
Figure lD-24 Installing Diode
Negative Diodes1. Using Tool J-23526, press diode into support. See
Figure lD-25. Insert negative diode pigtail lead
through tool pilot.
Alternator Reassembly1. Clean and inspect all parts. Check brushes. Re-
place them if they have worn down to
3/8 inch.
2. Lubricate both bearings with special ball bearing
lubricant.
3. Press rear bearing on rotor shaft and install front
bearing into drive end frame.
4. Assemble stator together with windings into rear
end frame.
5. Install both diode supports.
6. Solder diode connections and ends of stator wind-
ings together. Since diodes are very sensitive to heat,
solder quickly using a very hot soldering iron.

I
;
I
1 D- 361973 OPEL SERVICE MANUALI‘\
Figure 1 D-27 Alternator - Exploded View301D27

1 E- 381973 OPEL SERVICE MANUAL
4. Turn switch on to see if wiper niotor will function
with wiper linkage’detached. If wiper motor will ndt
run, disconnect connector at wiper motor and co?-
nect hot lead from battery to terminal No. 53 onwiper motor. If wiper motor runs, the wiper switch
is faulty or there is an break in the lead wire. If wiper
motor still will not run, remove and bench test.
MAJOR REPAIRWIPER TRANSMISSIONS
Removal (1900 and Manta)1. Remove wiper blade (2).
2. Remove the wiper transmission retaining nut,
washer, and rubber seal ring. See .Figure lE-1.
Figure lE-1 Crank Arm Retaining Nut3. Remove instrument cluster housing.
If only left wiper transmission is to be serviced, it can
be done without removing any ‘other instrument
panel components. If the right side, or both, trans-
missions are to be serviced, then
it will be necessary
for complete instrument panel removal. On the Ral-
lye models, the gauge carrier must also be remove&Qn all
1900 and Manta Models the defroster ducts
are secured to the instrument panel cover, by two (‘2)
spring clips, and should not be removed from
dayhcover. Remove cover and duct as, a unit.
4. Remove retaining clips from transmission co;-netting rod pins. Pull connecting rods off pins. See
Item “A”, Figure lE-2.
5. Remove the screws securing the wiper transmis-
sion to the inner side of the cowl (Items “B”, Figuie
13), and remove the transmission assemblies.I
Figure lE-2 Connecting Rod Retaining Clips
Installation1. Place wiper transmissions into position at cowl
and install holding screws.
2. Push connecting rods onto transmission cranking
arm pins and install retaining clips. See Figure lE-2,
Item “A”.
3. Reinstall dash and instrument cluster parts.
4.
1nst:all the rubber seal ring, washer, and transmis-
sion retaining nut. See Figure IE-1.
5. Install wiper blades and check the position of the
blades in the park position. See Figure lE-3.
Figure lE-3 Wiper Blades in Park Position
Removal and Installation of GT W/per Transmission1. Remove nuts and remove both wiper
arms. See
Figure lE-4.
2. Remove three (3) bolts from each windshield

1 E- 40 1973 OPEL SERVICE MANUALDisassemblyI
1. Remove two (2) motor housing attaching
screw$(Item No. 4) and two (2) angle brackets (Item No.
3). See Figure lE-9.
Figure 1 E-S Removing Motor Housing Attaching
SCFS”JSFigure
1 E-l 0 Transmission and Armature Removed
from Motor Housing2. Remoyz transmission housing together with arma-
ture from motor housing. See Figure lE-10. It may
be necessary to hold armature in transmission hous-
ing with a screw driver.
3.
Rem~ove armature from transmission housing.
4. Remove five (5) transmission housing cover
screws. See Figure lE-11.Figure 1 E-l 1 Remove Transmission Housing CoverSCEWS
5. Remove cover, gasket and driven gear from trans-
mission housing. See Figure IE-12. Remove pivot
ball from driven gear. See Figure lE-15.
Figure 1 E-l 2 Remove Driven Gear
6. If required, remove brushes.
a. To remove positive brushes, cut brush leads off at
brush holder. See Figure lE-13.
b. To remove negative brush, remove brush retaining
screw from commutator end frame. See Figure
lE-
14.