1988 OPEL CALIBRA oil pressure

32Release the securing clips and remove the
main outer timing belt cover, then unclip the
smaller outer timing belt cover from the
coolant pump.
33Turn the crankshaft through at least
quarter of a turn clockwise using a socket or
spanner on the crankshaft sprocket bolt.
34If the special gauge is available, place the
locked gauge at the centre of the belt run
between the coolant pump and the camshaft
sprocket. The gauge should locate on the
timing belt (see illustration).
35Slowly release the operating lever on the
gauge, then lightly tap the gauge two or three
times, and note the reading on the scale (see
illustration).
36If the reading is not as specified, loosen
the three coolant pump securing bolts, and
rotate the pump in the required direction to
achieve the desired reading on the gauge.
Rotate the pump clockwise to increase the
belt tension, or anti-clockwise to decrease the
tension.
37Lightly tighten the coolant pump securing
bolts.
38Remove the tensioning gauge, and turn
the crankshaft through one full turn clockwise.
39Re-check the belt tension as described in
paragraphs 4 and 5.
40If the tension is not as specified, repeat
paragraphs 6 to 9 inclusive until the desired,
consistent, reading is obtained.
41On completion of adjustment, remove the
checking gauge, tighten the coolant pump
bolts to the specified torque, and refit the
outer timing belt covers.
42If the special checking gauge is not
available, the timing belt tension can be
checked approximately by twisting the belt
between the thumb and forefinger, at the
centre of the run between the coolant pump
and the camshaft sprocket. It should just be
possible to twist the belt through 90°using
moderate pressure (see illustration). If
adjustment is necessary, continue as
described previously in this Section, but have
the belt tension checked by a Vauxhall dealer
using the special gauge at the earliest
opportunity. If in doubt, err on the tight side
when adjusting the tension, as if the belt is too
slack, it may jump on the sprockets, which
could result in serious engine damage.12Timing belt and tensioner 1.4
and 1.6 models (not C16 NZ2) -
removal, refitting and adjustment
3
Removal
1Remove the timing belt outer covers as
described in Section 11, paragraphs 1 to 5.
2To lock the tensioner in its slackest position
for removal and refitting, move the tensioner
indicator arm clockwise until the holes align in
the baseplate and the arm. Then insert a
close-fitting pin, such as a drift, to retain them
(see illustration). The tensioner can then be
unbolted, or the belt can be removed.
3Check that the tensioner roller rotates
smoothly and easily, with no noises or signs
of free play, roughness or notchy movement.
Check also that there is no sign of physical
wear or damage. If the tensioner is faulty in
any way, or if there is any reason to doubt the
continued efficiency of its spring, the
complete assembly must be renewed.
Refitting
4On refitting, ensure that the tensioner
baseplate lug engages with the hole in the oil
pump housing, then tighten the tensioner bolt
securely and remove the locking pin; the
tensioner should be quite free to move.
5Set the belt tension as described below.
Adjustment
6Whenever the timing belt is disturbed,
whether during belt renewal or any otherengine overhaul work, its tension must be set
on assembly - note that this procedure must
only be carried out on a cold engine.
7It is assumed that the belt has been
removed and refitted, i.e. that the crankshaft
pulley and timing belt outer covers are
removed, that the tensioner is unlocked (see
above) and that No 1 cylinder is in its firing
position (just before TDC on the compression
stroke). Temporarily refit the crankshaft pulley
bolt and remove the spark plugs so that the
crankshaft can be rotated easily.
8Note also that turning the coolant pump
with the precision required is a great deal
easier if a special spanner (Kent-Moore Part
No KM-421-A) is used. Alternatives are
available from manufacturers such as
Sykes-Pickavant (Part No 031300) (see
illustration).
9With the belt refitted and correctly routed
(see Section 11), ensure that the punch mark
on the crankshaft sprocket and the stamped
line on the camshaft sprocket are aligned with
their respective timing belt rear cover notches
(see illustrations).
10Tighten the belt by slackening its three
securing bolts, and turning the coolant pump
clockwise until the holes align in the tensioner
indicator arm and baseplate (the tensioner
indicator arm will then have moved fully
clockwise to its stop). Lightly tighten the
pump securing bolts, just sufficiently to
prevent the pump from moving.
11Using a spanner applied to the crankshaft
pulley bolt, turn the crankshaft smoothly
2A•16SOHC engine procedures
11.34 Tension blade KM-510-A correctly
positioned on timing belt. Belt must pass
through points A, B and C - SOHC engines11.42 Checking timing belt tension by
twisting belt through 90º between thumb
and forefinger
12.8 Using a special spanner to adjust the
timing belt by moving the coolant pump12.2 Using a close-fitting drift to lock the
tensioner. Note baseplate lug engaged in
oil pump housing (arrowed)
11.35 Note the reading on the scale of the
tension gauge -
1.6 litre engine

28Recover the cylinder head gasket and
discard it.
Refitting
29Clean the cylinder head and block mating
faces, and the camshaft housing and cylinder
head mating faces by careful scraping. Take
care not to damage the cylinder head and
camshaft housing, which are made of light
alloy and are easily scored. Cover the coolant
passages and other openings with masking
tape or rag to prevent dirt and carbon falling
in. Mop out all the oil from the bolt holes; if oil
is left in the holes, hydraulic pressure could
crack the block when the bolts are refitted.
30If desired, the cylinder head can be
dismantled and inspected as described in
Sections 22 and 23, and the camshaft
housing can be dismantled as described in
Section 18.31Begin refitting by locating a new gasket
on the block so that the word “OBEN” or
“TOP” can be read from above (see
illustrations).
32With the mating faces scrupulously clean,
locate the cylinder head on the block so that
the positioning dowels engage in their holes.
33Refit the hydraulic valve lifters, thrust
pads and rocker arms to the cylinder head in
their original positions. Liberally oil the valve
lifter bores, and if new lifters are being fitted
initially immerse each one in a container of
clean engine oil and compress it (by hand)
several times to charge it. Lubricate the
contact faces of the valve lifters, thrust pads
and rocker arms with a little molybdenum
disulphide grease (see illustration).
34Temporarily refit the crankshaft sprocket,
and ensure that the timing marks are still
positioned as they were before the timing belt
was removed (see Section 11).35Apply sealing compound (Vauxhall part
No 90094714, or equivalent) to the cylinder
head top mating face (see illustration), then
refit the camshaft housing to the cylinder
head.
36Fit the new cylinder head bolts, ensuring
that the washers are in place under their
heads, and screw the bolts in by hand as far
as possible (see illustration).
37Tighten the bolts working from the inside
outwards in a spiral pattern as shown (see
illustration). Tighten the bolts in the four
stages given in the Specifications -i.e. tighten
all bolts to the Stage 1 torque, then tighten all
bolts to Stage 2 and so on (see illustrations).
38Further refitting is a reversal of the
removal procedure, remembering the
following points.
39Ensure that the HT leads are refitted to
their correct cylinders.
SOHC engine procedures 2A•21
20.25B . . . and their thrust pads from the
cylinder head - 1.6 litre engine
20.35 Apply sealing compound to the
cylinder head top mating face20.33 Lubricate the valve lifter contact
faces with molybdenum disulphide grease20.31B Cylinder head gasket correctly
located over dowel in cylinder block
20.31A Cylinder head gasket “Oben/TOP”
markings20.27 Lifting the cylinder head from the
cylinder block - 1.6 litre engine20.26 Lift the hydraulic valve lifters from
the cylinder head - 1.6 litre engine
20.25A Lift the rocker arms . . .20.24 Lifting the camshaft housing from
the cylinder head - 1.6 litre engine
2A

40Refit the camshaft sprocket and the
timing belt and tension the timing belt as
described in Section 11.
41Where applicable, refit the manifolds to
the cylinder head, with reference to Chapter
4A, 4B or 4C, using new gaskets.
42Reconnect the exhaust downpipe to the
manifold, using a new gasket, referring to
Chapter 4C, if necessary.
43Refit the upper alternator mounting to the
inlet manifold, then adjust the alternator
drivebelt tension, as described in Chapter 5.
44Refill the cooling system, as described in
Chapter 3.
45On completion, check that all relevant
hoses, pipes and wires, etc., have been
reconnected.
46When the engine is started, check for
signs of leaks.
47Once the engine has reached normal
operating temperature, check and if
necessary adjust the idle speed (where
applicable) and the mixture (where
applicable), with reference to Chapter 4A or
4B.
21Cylinder head - removal and
refitting (engine removed)
4
Note: New cylinder head bolts and a new
cylinder head gasket must be used on
refitting, and sealer will be required when
refitting the camshaft housing.
The torque settings stated are only applicable
to latest specification head bolts, available
from Vauxhall. Earlier type or alternative make,
head bolts may require different torques.
Consult your supplier.
Removal
1The cylinder head can be removed
complete with the manifolds, or the manifolds
can be detached from the cylinder head
before removal, with reference Chapter 4A,
4B or 4C.
2Remove the timing belt and the camshaft
sprocket, as described in Section 11.
3Unscrew the two upper rear timing belt
cover securing bolts from the camshaft
housing (see illustration).4Disconnect the HT leads from the spark
plugs, labelling them if necessary to aid
refitting, and remove the distributor cap
referring to Chapter 5.
5If not already done, disconnect the stub
hose that connects the crankcase breather
tube to the camshaft housing. If applicable,
unscrew the bolt securing the crankcase
breather tube bracket to the end of the
cylinder head.
6Make a final check to ensure that all
relevant hoses, pipes and wires have been
disconnected.
Refitting
7Proceed as described in Section 21,
paragraphs 23 to 41 inclusive, but in addition
note the following.
8On completion check that all relevant
hoses, pipes and wires, etc., have been
reconnected.
22Cylinder head -dismantling
and reassembly
4
Note: A valve spring compressor tool will be
required for this operation. New valve stem oil
seals must be used on reassembly
Dismantling
1With the cylinder head removed as
described in Section 21, clean away all
external dirt.
2If not already done, remove the thermostat
housing, and on 1.4 and 1.6 litre models, thethermostat, as described in Chapter 3.
Remove the manifolds as described in
Chapter 4A, 4B or 4C. Remove the spark
plugs if not already done.
3To remove a valve, fit a valve spring
compressor tool. Ensure that the arms of the
compressor tool are securely positioned on
the head of the valve and the spring cap (see
illustration).
4Compress the valve spring to relieve the
pressure of the spring cap acting on the
collets. If the spring cap sticks on the valve
stem, support the compressor tool and give
the end a light tap with a hammer to help free
the spring cap.
5Extract the two split collets, then slowly
release the compressor tool.
6Remove the spring cap, spring, valve stem
oil seal, and the spring seat, then withdraw
the valve.
2A•22SOHC engine procedures
20.36 Fit new cylinder head bolts, ensuring
that the washers are in place20.37B Tighten the cylinder head bolts to
the specified torque . . .
22.3 Valve spring compressor tool fitted to
No 1 exhaust valve - 2.0 litre engine21.3 Upper rear timing belt cover securing
bolts (arrowed) - 1.6 litre engine
20.37C . . .then through the specified
angle - 2.0 litre engine
20.37A Cylinder head bolt tightening
sequence - SOHC engines

23Cylinder head - inspection
and renovation
4
Note: Refer to a dealer for advice before
attempting to carry out valve grinding or valve
seat reciting operations, as these operations
may not be possible for the DIY mechanic.
This is due to the fitment of hardened valve
seats for use with unleaded petrol
Inspection
1Remember that the cylinder head is of light
alloy construction and is easily damaged, use
a blunt scraper or rotary wire brush to clean all
traces of carbon deposits from the
combustion spaces and the ports. The valve
stems and valve guides should also be freed
from any carbon deposits. Wash the
combustion spaces and ports down with
paraffin and scrape the cylinder head surface
free of any foreign matter with the side of a
steel rule, or a similar article.
2If the engine is installed in the car, clean the
pistons and the top of the cylinder bores. If
the pistons are still in the block, it is essential
that great care is taken to ensure that no
carbon gets into the cylinder bores. This could
scratch the cylinder walls or cause damage to
the pistons and rings. To ensure this does not
happen, first turn the crankshaft so that two of
the pistons are at the top of their bores. Insert
rag into the other two bores or seal them off
with paper and masking tape. The waterways
should also be covered with small pieces of
masking tape, to prevent particles of carbon
entering the cooling system and damaging the
coolant pump.
3Press a little grease into the gap between
the cylinder walls and the two pistons that are
to be worked on. With a blunt scraper,
carefully scrape away the carbon from the
piston crown, taking great care not to scratch
the aluminium. Also scrape away the carbon
from the surrounding lip of the cylinder wall.
When all carbon has been removed, scrape
away the grease that will now be
contaminated with carbon particles, taking
care not to press any into the bores. To assist
prevention of carbon build-up, the piston
crown can be polished with a metal polish.
Remove the rags or masking tape from the
other two cylinders, and turn the crankshaft
so that the two pistons that were at thebottom are now at the top. Place rag or
masking tape in the cylinders that have been
decarbonised, and continue as just described.
4Examine the heads of the valves for pitting
and burning, especially the heads of the
exhaust valves. The valve seatings should be
examined at the same time. If the pitting on
the valve and seat is very slight, the marks
can be removed by grinding the seats and
valves together with coarse, and then fine,
valve grinding paste.
5Where bad pitting has occurred to the valve
seats, it will be necessary to recut them and fit
new valves. This latter job should be entrusted
to the local dealer or engineering works. In
practice it is very seldom that the seats are so
badly worn. Normally it is the valve that is too
badly worn for refitting, and the owner can
easily buy a new set of valves and match
them to the seats by valve grinding.
Renovation
6Valve grinding is carried out as follows.
Smear a trace of coarse carborundum paste
on the seat face and apply a suction grinder
tool to the valve head. With a semi-rotary
motion, grind the valve head to its seat, lifting
the valve occasionally to redistribute the
grinding paste. When a dull matt even surface
is produced on both the valve seat and the
valve, wipe off the paste and repeat the
process with fine carborundum paste, lifting
and turning the valve to redistribute the paste
as before. A light spring placed under the
valve head will greatly ease this operation.
When a smooth unbroken ring of light grey
matt finish is produced, on both valve and
valve seat faces, the grinding operation is
complete. Carefully clean away every trace of
grinding compound, taking great care to leave
none in the ports or in the valve guides. Clean
the valves and valve seats with a
paraffin-soaked rag, then with a clean rag,
and finally, if an air line is available, blow the
valves, valve guides and valve ports clean.
7Check that all valve springs are intact. If any
one is broken, all should be renewed. Check
the free height of the springs against new
ones. If some springs are not long enough,
replace them all. Springs suffer from fatigue
and it is a good idea to renew them even if
they look serviceable. 8The cylinder head can be checked for
warping either by placing it on a piece of plate
glass or using a straight-edge and feeler
blades. If there is any doubt or if its block face
is corroded, have it re-faced by your dealer or
motor engineering works.
9On 1.8 and 2.0 litre, always renew the
sealing ring between the cylinder head and
the thermostat housing when the head is
removed for overhaul (see illustration).
Reference to Chapter 21 will show that a
considerable amount of work is involved if it is
wished to renew the sealing ring with the
cylinder head installed.
10If the oil pressure regulating valve in the
cylinder head is to be renewed, access is
gained through the circular plug covering the
end of the valve (see illustration). The old
valve must be crushed, then its remains
extracted, and a thread (M10) cut in the valve
seat to allow removal using a bolt. A new
valve and plug can then be driven into
position. In view of the intricacies of this
operation, it is probably best to have the valve
renewed by a Vauxhall dealer if necessary.
24Hydraulic valve lifters -
inspection
4
Inspection
1On engines that have covered a high
mileage, or for which the service history
(particularly oil changes) is suspect, it is
possible for the valve lifters to suffer internal
contamination. In extreme cases this may
result in increased engine top end noise and
wear. To minimise the possibility of problems
occurring later in the life of the engine, it is
advisable to dismantle and clean the hydraulic
valve lifters as follows whenever the cylinder
head is overhauled. Note that no spare parts
are available for the valve lifters, and if any of
the components are unserviceable, the
complete assembly must be renewed (see
illustration).
2With the cylinder head removed and
dismantled as described in Sections 21 and
23, first inspect the valve lifter bores in the
2A•24SOHC engine procedures
23.10 Oil pressure regulating valve (1) and
plug (2) - 2.0 litre engine23.9 Renewing the thermostat housing
sealing ring - 2.0 litre engine
Warning: The exhaust valves
fitted to 20 XEJ and C 20 XE
(DOHC) models are fitted with
sodium to improve their heat
transfer. Sodium is a highly reactive
metal, which will ignite or explode
spontaneously on contact with water
(including water vapour in the air). These
must NOT be disposed of with ordinary
scrap. Seek advice from a Vauxhall dealer
or your Local Authority, if the valves are to
be disposed of.

18If the engine is in the vehicle, further
refitting is a reversal of the removal
procedure, but refit the front section of the
exhaust system referring to Chapter 4C. On
completion, refill the engine with oil, as
described in Chapter 1.
30Oil pump - removal and
refitting
4
Removal
1Remove the timing belt, sprockets and the
rear timing belt cover, as shown in Section 11.
2Remove the sump, oil pick-up pipe and
sump baffle (where applicable), as described
in Section 29.3On C 16 NZ2, 1.8 and 2.0 litre engines,
unscrew the oil filter from its mounting on the
oil pump, referring to Chapter 1, if necessary.
4Disconnect the wiring from the oil pressure
switch mounted on the oil pump.
5Remove the securing bolts, and withdraw
the oil pump from the cylinder block. Recover
the gasket.
6The oil pump can be dismantled for
inspection, as described in Section 31.
Refitting
7Thoroughly clean the mating faces of the oil
pump and cylinder block, then locate a new
gasket on the block (see illustration).
8Before refitting the oil pump, steps must be
taken to protect the oil seal lips from damage,
and from turning back on the shoulder at the
front end of the crankshaft. Grease the seallips, and then wind tape around the
crankshaft to form a gentle taper.
9Refit the oil pump, ensuring that the inner
gear engages with the flats on the crankshaft,
and tighten the securing bolts to the specified
torque, then remove the tape from the end of
the crankshaft (see illustrations).
10Reconnect the wiring to the oil pressure
switch.
11On C 16 NZ2, 1.8 and 2.0 litre engines, fit
a new oil filter, with reference to Chapter 1.
12Refit the sump baffle (where applicable),
oil pick-up tube and sump, as described in
Section 29.
13Refit the rear timing belt cover and the
timing belt, and tension the timing belt as
described in Section 11.
31Oil pump - dismantling,
inspection and reassembly
4
Note: A new crankshaft front oil seal must be
used on reassembly
Dismantling
1With the oil pump removed as described in
Section 30, continue as follows.
2Remove the securing screws and withdraw
the rear cover (see illustration). The screws
may be very tight, in which case it may be
necessary to use an impact driver to remove
them.
2A•28SOHC engine procedures
29.16 Refitting the oil pick-up pipe bracket
- 2.0 litre engine29.17B Refitting the sump - 2.0 litre engine
31.2 Removing an oil pump rear cover
securing screw -
2.0 litre SOHC engine30.9C Tighten the oil pump securing bolts
to the specified torque -
2.0 litre SOHC engine30.9B . . .and with two flats (arrowed) on
1.8 and 2.0 litre engines
30.9A Oil pump inner gear must engage
with hexagon flats on crankshaft (arrowed)
on 1.4 and 1.6 litre engines . . .30.7 Fit a new oil pump gasket to the
cylinder block - 2.0 litre engine
29.17A Coat the sump securing bolts with
thread-locking compound before fitting

Inspection
3Check the clearance between the inner and
outer gear teeth (backlash) using a feeler
blade (see illustration).
4Check the clearance between the edges of
the gears and the housing (endfloat) using a
straight edge and a feeler blade (see
illustration).
5If any of the clearances are outside the
specified limits, renew the components as
necessary.
6Ensure that the gears and the interior of the
pump body are scrupulously clean before
reassembly, and note that the outer gear is
marked with a punch dot to indicate the gear
outer face.
7The oil pressure relief valve components
can be removed from the pump by
unscrewing the cap (see illustration).
Examine the spring and plunger, and renew if
necessary.
Reassembly
8Thoroughly clean the components before
refitting.
9Always renew the crankshaft front oil seal at
the front of the oil pump housing. Prise out the
old seal using a screwdriver, and fit the new
seal using a socket or tube, so that it is flush
with the outer face of the housing (see
illustrations).
10Ensure that the mating faces of the rear
cover and the pump housing are clean, then
coat the pump housing mating face with
sealing compound (Vauxhall part No
90485251, or equivalent) and refit the rear
cover. Refit and tighten the securing screws.
11Refit the pump, as described in Section 30.
32Pistons and connecting rods
- removal and refitting
4
Note: New big-end cap bolts must be used on
refitting
Removal
1Remove the cylinder head, as described
previously in Section 20.
2Remove the sump, oil pick-up pipe and
sump baffle (where applicable), as described
in Section 29.3If the connecting rods and big-end caps are
not marked to indicate their positions in the
cylinder block (i.e. cylinder numbers),
centre-punch them at adjacent points either
side of the cap/rod joint. Note to which side of
the engine the marks face (see illustration).
4Unscrew the big-end cap bolts from the
first connecting rod, and remove the cap. If
the bearing shells are to be re-used, tape the
cap and shell together.
5Check the top of the piston bore for a wear
ridge. If evident, carefully scrape it away with
a ridge reaming tool, otherwise as the piston
is pushed out of the block, the piston rings
may jam against the ridge.
6Place the wooden handle of a hammer
against the bottom of the connecting rod, and
push the piston/rod assembly up and out of the
cylinder bore. Recover the bearing shell, and
tape it to the connecting rod if it is to be re-used.
7Remove the remaining three assemblies in
a similar way. Rotate the crankshaft as
necessary to bring the big-end bolts to the
most accessible position.
8The piston can be separated from the
connecting rod by removing the circlips that
secure the fully floating gudgeon pin. Note the
orientation of the piston and connecting rod
before separation, and if necessary, make
alignment marks. Reassembly is a reversal of
dismantling ensuring that the piston and
connecting rod are correctly orientated.
9The pistons and connecting rods can be
examined for wear and damage, as described
in Section 33, and the bearings can be
examined as described in Section 35.
Refitting
10Begin reassembly by laying the
piston/connecting rod assemblies out in their
correct order, complete with bearing shells,
ready for refitting into their respective bores in
the cylinder block.
11Ensure that the seats for the bearing
shells are absolutely clean, and then fit the
shells into the seats.
12Wipe out the cylinder bores and oil them.
Oil the piston rings liberally, and ensure that
the ring gaps are positioned as described in
Section 33.
13Fit a piston ring compressor tool to the
first assembly to be installed.
SOHC engine procedures 2A•29
31.7 Oil pressure relief valve components
- 2.0 litre SOHC engine
32.3 Big-end cap centre punch
identification marks (circled). Note that lug
on bearing cap faces flywheel end of
engine - 2.0 litre SOHC engine
31.9B . . .and fit the new seal using a
socket - 2.0 litre SOHC engine31.9A Prise out the old crankshaft front
oil seal . . .
31.4 . . .and between the edges of the
gears and the housing -
2.0 litre SOHC engine31.3 Check the clearance between the
inner and outer gear teeth . . .
2A

31Refit the previously removed
components, referring to the relevant
Sections of this Chapter.
35Crankshaft and bearings -
examination
4
Examination
1Examine the crankpin and main journal
surfaces for signs of scoring or scratches, and
check the ovality and taper of the crankpins
and main journals. If the bearing surface
dimensions do not fall within the tolerance
ranges given in the Specifications at the
beginning of this Chapter, the crankpins
and/or main journals will have to be reground.
2Big-end and crankpin wear is accompanied
by distinct metallic knocking, particularly
noticeable when the engine is pulling from low
revs, and some loss of oil pressure.
3Main bearing and main journal wear is
accompanied by severe engine vibration rumble
- getting progressively worse as engine rev’s
increase - and again by loss of oil pressure.
4If the crankshaft requires regrinding, take it
to an engine reconditioning specialist, who
will machine it for you and supply the correct
undersize bearing shells.
5Inspect the big-end and main bearing shells
for signs of general wear, scoring, pitting and
scratches. The bearings should be matt grey
in colour. With leadindium bearings, should a
trace of copper colour be noticed, the
bearings are badly worn, as the lead bearing
material has worn away to expose the indium
underlay. Renew the bearings if they are in
this condition, or if there are any signs of
scoring or pitting. You are strongly advised
to renew the bearings - regardless of their
condition at time of major overhaul.
Refitting used bearings is a false economy.
6The undersizes available are designed to
correspond with crankshaft regrind sizes. Thebearings are in fact, slightly more than the
stated undersize, as running clearances have
been allowed for during their manufacture.
7Main and big-end bearing shells can be
identified as to size by the marking on the
back of the shell. Standard size shell bearings
are marked STD or .00, undersize shells are
marked with the undersize such as 0.020 u/s.
This marking method applies only to
replacement bearing shells, and not to those
used during production.
8An accurate method of determining bearing
wear is by using a Plastigage. The crankshaft
is located in the main bearings (and, if
necessary, the big-end bearings), and the
Plastigage filament is located across the
journal. Vauxhall recommend that the
crankshaft journal and bearing shells are
lightly lubricated, to prevent the Plastigage
from tearing as the bearing cap is removed.
The bearing cap should be fitted, and the
bolts tightened to the specified torque. The
cap is then removed, and the width of the
filament is checked against a scale that shows
the bearing running clearance. The clearance
should be compared with that given in the
Specifications.
9Where applicable, check the teeth of the
crankshaft TDC sensor wheel for damage
(see illustration). If evident, the crankshaft
must be renewed.
10Similarly, check the condition of the pins
in the front crankshaft balance weight, which
serve as detect points for the plug-in
diagnostic sensor used by Vauxhall dealers
(see illustration).
36Cylinder block and bores -
examination and renovation
4
Examination
1Examine the cylinder bores for taper,
ovality, scoring and scratches. Start bycarefully examining the top of the cylinder
bores. If they are at all worn, a very slight
ridge will be found on the thrust side. This
marks the top of the piston ring travel. The
owner will have a good indication of the bore
wear before dismantling the engine, or
removing the cylinder head. Excessive oil
consumption, accompanied by blue smoke
from the exhaust, is a sure sign of worn
cylinder bores and piston rings.
2Measure the bore diameter across the
block, and just below any ridge. This can be
done with an internal micrometer or a dial
gauge. Compare this with the diameter of the
bottom of the bore, which is not subject to
wear. If no measuring instruments are
available, use a piston from which the rings
have been removed, and measure the gap
between it and the cylinder wall with a feeler
blade. Refer to the Specifications. If the
cylinder wear exceeds the permitted
tolerances, then the cylinders will need
reboring, in which case note the following
points:
a)Piston and cylinder bores are closely
matched in production. The actual
diameter of the piston is indicated by
numbers on its crown; the same numbers
stamped on the crankcase indicate the
bore diameter
b)After reboring has taken place, the
cylinder bores should be measured
accurately and oversize pistons selected
from the grades available to give the
specified piston-to-bore clearance
c)For grading purposes, the piston diameter
is measured across the bottom of the skirt
3If the wear is marginal and within the
tolerances given, new special piston rings can
be fitted to offset the wear.
4Thoroughly examine the crankcase and
cylinder block for cracks and damage, and
use a piece of wire to probe all oilways and
waterways to ensure that they are
unobstructed.
SOHC engine procedures 2A•33
35.10 Check the condition of the pins (arrowed) in the front
crankshaft balance weight - 2.0 litre SOHC engine35.9 Check the condition of the TDC sensor wheel teeth at the
front of the crankshaft - 2.0 litre SOHC engine
2A

5Note that the rubber plug located next to
the bellhousing flange on the cylinder block
covers the aperture for the installation of a
diagnostic TDC sensor. The sensor, when
connected to a monitoring unit, indicates TDC
from the position of the pins set into the
crankshaft balance weight.
37Examination and renovation
-general
4
General
1With the engine completely stripped, clean all
components and examine them for wear. Each
component should be checked, and where
necessary renewed or renovated, as described
in the relevant Sections of this Chapter.
2Renew main and big-end bearing shells as
a matter of course, unless it is known that
they have had little wear, and are in perfect
condition.
3If in doubt whether to renew a component
that is still just serviceable, consider the time
and effort that will be incurred should the
component fail at an early date after rebuild.
Obviously, the age and expected life of the
vehicle must influence the standards applied.4Gaskets, oil seals and O-rings must all be
renewed as a matter of routine. Flywheel,
cylinder head, and main and big-end bearing
cap bolts must be renewed, because of the
high stress to which they are subjected.
5Renew the engine core plugs while they are
easily accessible, if they show signs of
leakage. Knock out the old plugs with a
hammer and chisel or punch. Clean the plug
seats, smear the new plugs with sealing
compound, and tap them squarely into
position.
38Initial start-up after major
overhaul or repair
2
1Make a final check to ensure that
everything has been reconnected to the
engine, and that no rags or tools have been
left in the engine compartment.
2Check that oil and coolant levels are
correct.
3Start the engine. This may take a little longer
than usual, as fuel is pumped to the engine.
4Check that the oil pressure warning lamp
goes out when the engine starts. This may
take a few seconds as the new oil filter fills
with oil.5Run the engine at a fast tickover, and check
for leaks of oil, fuel and coolant. If a new
camshaft has been fitted, pay careful
attention to the running-in procedure given in
Section 18, paragraphs 17 and 18. Where
applicable, check the power steering and/or
automatic transmission fluid cooler unions for
leakage. Some smoke and odd smells may be
experienced, as assembly lubricants and
sealers burn off the various components.
6Bring the engine to normal operating
temperature. Check the ignition timing, idle
speed and the mixture (where applicable), as
described in Chapter 4A or 4B.
7Allow the engine to cool, then recheck the
oil and coolant levels. Top-up if necessary
8If new bearings, pistons, etc., have been
fitted, the engine should be run-in at reduced
speeds and loads for the first 500 miles (800
km) or so. It is beneficial to change the engine
oil and filter after this mileage.
2A•34SOHC engine procedures