Contents - Volkspage

5B.4 Ignition systems
4.7a Carefully prise off the rotor arm . . .
7 Carefully prise off the rotor arm, then lift off
the moisture shield (see illustrations).
8 Mark the relationship between the
distributor body and the drive gear case
flange by scribing arrows on each. Slacken
and remove the clamp bolts, then withdraw
the distributor body from the cylinder head.
Recover the seals, shims and washers (where
applicable), noting their order of fitment to
ensure correct reassembly later (see
illustrations).
Inspection
9 Recover the O-ring seal from the bottom of
the distributor and inspect them. Renew them
if they appear at all worn or damaged.
10 Inspect the teeth of the distributor drive
gear for signs of wear or damage. Any slack in
the distributor drive train will affect ignition
timing. Renew the distributor if the teeth of the
drive gear appear worn or chipped.
Refitting
11 Before progressing, check that the engine
is still set to TDC on cylinder No 1 - refer to
Chapter 2A for guidance.
12 Install the distributor and loosely fit the
clamp bolt; it may be necessary to rotate the
shaft slightly to allow it to engage with the
camshaft drive gear. Rotate the distributor
body such that the alignment marks made
during removal line up.
13 The shaft is engaged at the correct angle
when the rotor arm electrode is pointing at the
No 1 cylinder mark on the distributor body
(taking into account the offset for the basic
ignition timing setting).
14 Refit the distributor cap, pressing the
retaining clips firmly into place/ tightening the
retaining screws (as applicable).
15 Reconnect the Hall sensor cabling to the
distributor.
16 Where applicable, refit the screening cap,
tightening the screws securely.
17 Working from the No 1 terminal, connect
the HT leads between the spark plugs and
the distributor cap. Note that the firing order is
l-3-4-2.
18 Fit the HT king lead between the coil and
the centre terminal on the distributor cap.
19 It will now be necessary to have the
ignition timing checked and if necessary
adjusted - refer to the notes in Section 5.
4.7b . . . then lift off the moisture shield 4.8a Slacken and remove
the clamp bolts . . .
4.8b . . .then withdraw the distributor
body from the cylinder head . . .
Note: The engine should be at normal
operating temperature to ensure correct
results
Note: Accurate checking and setting of the
ignition timing is only possible using a special
instrument connected to the flywheel TDC
sender unit through the aperture in the top of
the gearbox be//housing. This will not normally
be available to the home mechanic, so a
method using a stroboscopic timing light is
described below. It should be noted that this
only provides an approximate setting - it is
recommended that the vehicle be checked by
a VW dealer at the earliest opportunity.
1 Disable the engine by unplugging the
multiway Hall sender connector from the
distributor.
2 Using a spanner or socket and wrench on
the crankshaft pulley, turn the engine
manually until the crankshaft pulley timing
mark (a notch cut into the edge of the pulley)
becomes visible. Clean the edge of the pulley,
then highlight the timing mark with chalk or a
dab of white paint. On G40 models, there are
two marks: the timing mark has a ‘Z’ stamped
next to it on the crankshaft pulley (the TDC
mark is indicated by an ‘0’).
3 Reconnect the distributor multiway plug,
then connect the stroboscopic timing light to
the engine in accordance with the
manufacturer’s instructions, so that it is
triggering from the No 1 cylinder HT lead.
4.8c Recover the seals
4 Start the engine and run it at idling speed.
Direct the beam from the timing light at the
pointer protruding from the timing belt cover.
The stroboscopic effect should ‘freeze’ the
motion of the crankshaft pulley and the
highlighted timing mark. If the mark appears
to be moving back and forth, this may be due
erratic idling - check that all of the cars
electrical accessories are switched off and
that the auxiliary cooling fan is not running.
The engine should be at normal operating
temperature, but the idle speed may be
become unstable if it is particularly hot day
and the engine has been idling for some time.
5 The highlighted timing mark should appear
to be stationary and aligned with the pointer
on the timing belt cover (see illustrations). If
they are not aligned, the basic ignition setting
requires adjustment.
6 To adjust the basic ignition timing setting,
first switch off the engine, to avoid the risk of
a getting a shock from the HT voltage. Refer
5.5a Ignition timing marks -
all models except G40