Opel 1900 1973, Service Manual

Page: 42 / 625

IGNITION SYSTEM
4. Rota&distributor counterclockwise slightly until
contact
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
Contact gap at widest gap) or dwell 50
degrees plus or
minus 3 degrees
should
always be
checked before adjusting ignition timing.
1. timing light to No. 1 spark plug.
2. Disconnect and plug vacuum advance unit and
retard
hoses.
3. Connect a tachometer from distributor side of coil
to
4. Start Set idle speed to 900 RPM.
5. distributor as necessary to align timing
marks. mark is a steel ball embedded in the
flywheel and a pointer in a window in the right fly-
wheel housing. See Figure
Ignition Timing Marks
6. clamp bolt securely and recheck timing
mark
7. Reconnect vacuum hoses and adjust engine idle
speed mixture.
WIRE INSPECTION
The and spark plug wires are of a special
resistance 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
Figure Checking Ignition Wire Resistance
CHECK IGNITION OUTPUT
1. Disconnect secondary coil 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).