1973 OPEL GT-R Service Manual

I
ilC- 201973 OPEL SERVICE MANUAL
There is also a plastic hood slipped over the distrivu-tar cap with an outlet for the ignition cables as an
added protection against moisture from the outside.
See Figure lC-2.
Figure lC-2 Ignition Distributor With Hood Installed
MAINTENANCE AND ADJUSTMENTS
CONTACT POINT REPLACEMENT
Removing Contact Points1. Remove contact support lock
,screw and remqve
contact point support. If condenser is to be replaced,
it will be necessary to replace condenser and
1eads;asan assembly.
Installing Contact Points1. Lightly lubricate distributor cam with high tein-perature cam and ball bearing lubricant. Excessive
lubricant will throw off into contact points.
:
,
2. Position support on breaker plate and install lock
screw leaving slightly loose for later adjustment..
3. Plug breaker arm wire in.
4. Adjust breaker point gap to ,016”.
/
DWELL ANGLE ADJUSTMENT
1. Connect dwell meter.
2. Remove distributor cap. Remove rotor. Loosen
breaker point set screw approximately
l/8 turn.
3. Insert screwdriver in notch of stationary breaker
point. Observe dwell meter while cranking engine.
Twist screwdriver as required to obtain a reading of
50 degrees plus or minus 3 degrees.4. Tighten breaker point set screw, then recheck
dwell.
5. Install rotor and cap.~Start engine and recheck
dwell. It is important that dwell be rechecked, as
instal~lation of rotor and cap will sometimes change
the dwell angle.
IGNITION TIMING ADJUSTMENT
Preliminary Timing (Engine Won’t Run)To time the ignition on any engine which will run,
use subparagraph b only. However, if the timing of
an engine is completely off, the following procedure
must first be used to get the engine to run.
1. With rocker arm cover removed, rotate crankshaft
in a clockwise direction until both valves for No. 1
cylinder are closed and the timing marks line-up.
(Valves are completely closed if rocker arms can be
“rocked” slightly.)
2. Install distributor in engine so that vacuum ad-
vance unit is in original position and notch in dis-
tributor rotor lines-up with notch in housing. See
Figure lC-3. If distributor does not seat in engine
block., turn distributor shaft so that rotor points
about 20 degrees clockwise from distributor timing
notch
(see Figure lC-18), then press lightly on dis-
tributor housing while cranking engine with starter.
After oil pump tang snaps into slot in distributor
shaft, start timing again from Step 1, leaving dis-
tributor installed.
Figure lC-3 Rotor Position for Filing No. 1 Cyliqder
3. Install distributor clamp and bolt, leaving bolt just
loose enough to permit movement of distributor. In-
stall distributor primary wire.L

IGNITION SYSTEMlC-214. Rota&distributor counterclockwise slightly until
contact pbints just start to open. This must be done
very carefully or engine will not start.
5. Install distributor cap. Make sure spark plug wires
are correctly installed in distributor cap, through clip
and on spark plugs.
Finish TimingIContact boint gap
(.016” at widest gap) or dwell 50
degrees plus or minus 3 degrees should always be
checked before adjusting ignition timing.
1. Connekt timing light to No. 1 spark plug.
2. Disconnect and plug vacuum advance unit and
retard u$it hoses.
3. Connect a tachometer from distributor side of coil
to
groun$l.4. Start dngine. Set idle speed to 900 RPM.
5. Rotate distributor as necessary to align timing
marks. T;ming mark is a steel ball embedded in the
flywheel and a pointer in a window in the right fly-
wheel housing. See Figure lC-4.:Figure lC-4 Ignition Timing Marks
6.
Tightq clamp bolt securely and recheck timing
mark ahgnment.
7. Reconnect vacuum hoses and adjust engine idle
speed
an: mixture.
IGNlTlOFj WIRE INSPECTION
1. The c$il and spark plug wires are of a specialresistance type. These secondary ignition wires
reduce television and radio interference.
2. Wipe ignition wires with a cloth moistened with
solvent and wipe dry. Bend wires to check for brittle,
cracked or swollen insulation. Defective insulation
will permit missing or cross-firing of spark plugs,
therefore any defective wires must be replaced.
3. If wire insulation is in good condition, clean any
terminals that are corroded and replace any termi-
nals that are broken or damaged. Terminals must tit
tight on spark plugs and in distributor cap.
4. Replace any hardened, cracked or loose cap nip-
ples or spark plug boots.
5. Check resistance of each wire from contact inside
distributor cap to spark plug or coil terminal. Re-
place any wire having over 10,000 ohms resistance
reading. See Figure lC-5.
Figure fC-5 Checking Ignition Wire Resistance
CHECK IGNITION OUTPUT
1. Disconnect secondary coil ivire so that engine will
not start. Connect a voltmeter from the battery side
of the coil primary to ground and check voltage
while engine is cranking. Reading should be 10 volts
or more. Low reading could be caused by a defective
battery, a discharged battery, high starter current
draw, a bad connection in the starter circuit or a bad
connection in the primary ignition circuit.
2. Connect an oscilloscope according to manufac-
turer’s instructions. Disconnect coil wire. Crank en-
gine and read coil output voltage. Reading should
exceed 20 KV (20,000 volts).

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

IGNITION SYSTEMlC- 23
9. Install:spark plugs using a 13/16 deep socket, an
extension and a torque wrench. Tighten to 22-29Ib.ft. 1
MAJOR REPAIRDlSTRlBtiTOR OVERHAULDistributbr Removal
1. Remove fuel pump. This is necessary because the
fuel
punp will block the distributor drive gear,
thereby preventing removal of the distributor. See
Figure lC-6.
2. Set No; 1 cylinder at firing point by turning engine
INOTCH IN STATIONARY& -.until cutout in distributor shaft (or rotor tip) points
to notch in distributor housing. See Figure
lC- 7.
3. Ball imbedded in flywheel should be approxi-
mately aligned with pointer in housing. See FigurelC-4.
4. Remove distributor hold-down clamp and remove
distributor. See Figure lC-8. Cover bore in timing
case to prevent foreign material from dropping into
engine. To make reinstallation of distributor easy, do
not rotate crankshaft or oil pump.
Disassembly
1. Remove distributor cap retaining spring clips, and
vacuum control units. See Figure lC-9.
Figure lC-9 Removing Retaining Clips
Figury lC-7 Aligning Shaft Cutout With Notch
Figure lC-8 Removing DistributorFigure lC-10 Removing Retaining Ring

1 C- 241973 OPEL SERVliTE MANUAL
2. Push retaining ring out of groove in
distribitorshaft. See Figure lC-10.I
3. Push up on distributor shaft. Remove breaker
plate from distributor housing. Remove breaker
points from breaker plate. See Figure lC-I 1.’
I
1
I3OlCl’l
Figure lC-1 1 Removing Breaker Plate:
4. Disassemble breaker plate by unscrewing Pall
thrust spring screw. Remove spring and ball.
.SeeFigure lC-12.3OlCi25. For cleaning, partly pull distributor shaft together
with centrifugal advance mechanism out of distribu-
tor housing. Do not disassemble advance mech-
anism.
6.
C!lean and check all parts. Replace any defective
parts.
7. Coat sliding parts of centrifugal advance mech-
anism and return springs with grease. See “A” in
Figure
lC- 13.
Figure lC-13 Lubricating Centrifugal Mechanism
Reassembly
1. Install new breaker points on breaker plate.
2. Install retaining ring on distributor shaft.
3. Install vacuum units, ignition condenser and cap
retaining
clios.Figure lC-12 Disassembling Breaker PlateFigure lC-14 Lubricating Upper Distributor

IGNITION SYSTEM1C. 25
4. Oil sliding parts of breaker plate at “B”. Oil felt
in cam at
“c”. Apply a thin layer of high melting
point grease to the cam, using a finger at “A”. See
Figure K-14.
/
5. Adjust breaker point gap to
,016 inches.
6. Grease control rod eye at “A”. See Figure lC-15.
Figure lC-15 Lubricating Control Rod Eye
7. Rein&all distributor cap nipples and spark plug
boots. If hardened or cracked, use new parts. See
Figure
l!C- 16.
/ Figure lC-16 Reinstalling Nipples
Distribu distributor shaft tang. See Figure lC-17.Figure lC-17 Oil Pump Slot
2. Inspect paper gasket on distributor housing and
replace if necessary.
3. Install distributor with vacuum units in original
position and with shaft cutout (rotor tip) in position
shown in Figure lC-18. Distributor shaft will turn as
distributor is installed, causing the rotor tip notch to
align with the housing notch when distributor is
seated.Figure
1C-18 Shaft Position for Starting Installation
4. Install distributor clamp, bolt and lockwasher tin-
ger tight. Align marks on rotor tip and housing.
5. Install fuel pump.
6. Adjust ignition timing.

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

IGNITION SYSTEMlC- 27
93OlC19
Figure 1 C-l 3 Distributor Exploded