spark plugs replace FORD SIERRA 1993 2.G Engine Electrical Systems Workshop Manual

41Locate the brush box over the
commutator, position the brushes, then fit the
nylon cover over the brushes. Route the brush
wiring into the locating channel, then secure
the brushes in the channels with the locking
clips and springs.
42Refit the commutator end housing,
locating the rubber block in the cut-out in the
housing, then secure with the two screws.
43Refit the spacers and C-clip to the end of
the armature shaft, then fit the commutator end
housing cap and secure with the two screws.
44Reconnect the wiring to the solenoid
terminal and fit the washer and securing nut.
Nippondenso type
45With the starter motor removed from the
vehicle and cleaned, grip the unit in a vice
fitted with soft jaw protectors.
46Unscrew the retaining nut and washer and
disconnect the wiring from the terminal on the
solenoid.
47Remove the two screws securing the
commutator end housing cap and remove the
cap (see illustration).
48Remove the C-clip from the groove in the
armature shaft, and remove the spring.
49Unscrew the two bolts and washers, and
withdraw the commutator end housing.
50Withdraw the two field brushes from the
brush plate, then remove the brush plate.
51If the brushes have worn to less than the
specified minimum, renew them as a set. To
renew the brushes, cut the leads at their
midpoint and make a good soldered joint
when connecting the new brushes.
52The commutator face should be clean and
free from burnt spots. Where necessary
burnish with fine glass paper (not emery) and
wipe with a fuel-moistened cloth. 53Position the brush plate over the end of
the armature, aligning the cut-outs in the
brush plate with the loops in the field
windings. The brush plate will be positively
located when the commutator end housing
bolts are fitted.
54Fit the brushes to their locations in the
brush plate, and retain with the springs.
55Fit the commutator end housing and
secure with the two bolts and washers.
56Fit the spring and the C-clip to the end of
the armature shaft, then smear the end of the
shaft with a little lithium-based grease, and
refit the commutator end housing cap,
securing with the two screws.
57Reconnect the wiring to the solenoid
terminal and fit the washer and retaining nut.
Note: The correct functioning of the spark plugs
is vital for the correct running and efficiency of
the engine. It is essential that the plugs fitted are
appropriate for the engine, and the suitable type
is specified at the beginning of this Chapter. If
this type is used and the engine is in good
condition, the spark plugs should not need
attention between scheduled replacement
intervals. Spark plug cleaning is rarely necessary
and should not be attempted unless specialised
equipment is available as damage can easily be
caused to the firing ends.
Removal
1Where necessary, for improved access
remove the air cleaner and/or the inlet hose.
2If necessary, identify each HT lead for
position, so that the leads can be refitted to theircorrect cylinders, then disconnect the leads
from the plugs by pulling on the connectors, not
the leads. Note that the position of No 1 cylinder
HT lead in the distributor cap is marked with
either a pip, or a number “1 “.
3On 2.0 litre DOHC carburettor models, the
location of the spark plugs and the close
proximity of the carburettor makes spark plug
access difficult, particularly when removing
the plugs from cylinders 2 and 3. It is
suggested that a 3/8 inch ratchet drive spark
plug socket with rubber insert and long
extension bar is used, possibly in conjunction
with a universal joint adapter. It is also
advisable to disconnect No 3 cylinder HT lead
from the distributor first, to allow some slack
for disconnection at the spark plug.
4Clean the area around each spark plug
using a small brush, then using a plug
spanner (preferably with a rubber insert),
unscrew and remove the plugs. Cover the
spark plug holes with a clean rag to prevent
the ingress of any foreign matter.
Inspection
5The condition of the spark plugs will tell
much about the overall condition of the engine.
6If the insulator nose of the spark plug is clean
and white, with no deposits, this is indicative of
a weak air/fuel mixture, or too hot a plug. (A hot
plug transfers heat away from the electrode
slowly - a cold plug transfers it away quickly).
7If the tip and insulator nose is covered with
hard black-looking deposits, then this is
indicative that the mixture is too rich. Should
the plug be black and oily, then it is likely that
the engine is fairly worn, as well as the mixture
being too rich.
8If the insulator nose is covered with light tan
to greyish brown deposits, then the mixture is
correct and it is likely that the engine is in
good condition.
9The spark plug gap is of considerable
importance, as, if it is too large or too small,
the size of the spark and its efficiency will be
seriously impaired. The spark plug gap should
be set to the figure given in the Specifications
at the beginning of this Chapter. To set it,
measure the gap with a feeler blade, and then
bend open, or close the outer plug electrode
until the correct gap is achieved (see
illustrations). The centre electrode should
never be bent as this may crack the insulation
and cause plug failure, if nothing worse.
11Spark plugs and HT leads -
removal, inspection and
refitting
5•12Engine electrical systems
10.47 Nippondenso starter motor brush assembly
1 Yoke
2 Solenoid connecting link
3 Pole shoe
4 Rubber grommet
5 Brush
6 Brush spring
7 Brush plate8 Commutator end housing
9 Bush
10 Spring
11 C-clip
12 Commutator end housing cap
13 Commutator end housing securing
bolt
11.9a Measuring a spark plug gap using a
feeler blade