SAAB 9000. Manual - part 19

2B•22 Engine removal and general overhaul procedures

18.8 Plastigauge in place on the crankshaft

main bearing journal

and if necessary corrected, the rings can be
fitted to the pistons.
9 Fit the piston rings using the same
technique as for removal. Fit the bottom (oil
control) ring first, and work up. When fitting
the oil control ring, first insert the expander,
then fit the lower and upper rings with the ring

gaps both on the non-thrust side of the piston,
with approximately 60° between them. Ensure
that the second compression ring is fitted the
correct way up, with the word "TOP"
uppermost. Arrange the gaps of the top and
second compression rings on opposite sides
of the piston, above the ends of the gudgeon
pin (see illustration). Note: Always follow any
instructions supplied with the new piston ring

sets - different manufacturers may specify
different procedures. Do not mix up the top
and second compression rings, as they have
different cross-sections.

Selection of new bearing shells

1 The main bearing shells are classified for

thickness as described in Section 15. Note
that up to the second undersize, it is possible
to mix different thicknesses of shell in order to
obtain the correct running clearance.
Commence the procedure with the two
thinnest shells, then if the clearance is too
great, fit one thick shell with one thin shell, and

make the check again. If the clearance is still

too great, fit two thick shells.

Main bearing running clearance

check

2 Clean the backs of the bearing shells, and
the bearing locations in both the cylinder block
and the main bearing caps.
3 Press the bearing shells into their locations,
ensuring that the tab on each shell engages in
the notch in the cylinder block or main bearing
cap location. Take care not to touch any
shell's bearing surface with your fingers.
4 The running clearance may be checked

using one of two methods.

18.9 Tightening a main bearing cap bolt

5 One method (which will be difficult to
achieve without a range of internal
micrometers or internal/external expanding
calipers) is to refit the main bearing caps to the
cylinder block/crankcase, with the bearing
shells in place. With the cap retaining bolts
correctly tightened, measure the internal

diameter of each assembled pair of bearing
shells. If the diameter of each corresponding
crankshaft journal is measured and then
subtracted from the bearing internal diameter,
the result will be the main bearing running
clearance.
6 The second (and more accurate) method is
to use a product known as "Plastigauge". This
consists of a fine thread of perfectly-round
plastic, which is compressed between the
bearing shell and the journal. When the cap
and shell are removed, the plastic is deformed,
and can be measured with a special card
gauge supplied with the kit. The running
clearance is determined from this gauge.
Plastigauge may be available from your Saab
dealer; otherwise, enquiries at one of the

larger specialist motor factors should produce

the name of a stockist in your area. The

procedure for using Plastigauge is as follows.
7 With the main bearing upper shells in place,
carefully lay the crankshaft in position. Do not
use any lubricant at this stage; the crankshaft

journals and bearing shells must be perfectly

clean and dry.
8 Cut several lengths of the appropriate-size

Plastigauge (they should be slightly shorter

than the width of the main bearings), and

place one length on each crankshaft journal
axis (see illustration). The length of
Plastigauge should be placed approximately

6.0 mm to one side of the centre-line of the
journal.
9 With the main bearing lower shells in
position, refit the main bearing caps, then
insert the bolts and tighten them progressively
to the specified torque (see illustration). Take
care not to disturb the Plastigauge, and do not

rotate the crankshaft at any time during this
operation.
10 Unscrew the bolts and remove the main
bearing caps, again taking great care not to
disturb the Plastigauge or rotate the
crankshaft.

18.11 Measuring the width of the deformed

Plastigauge using the card gauge

11 Compare the width of the crushed
Plastigauge on each journal to the scale
printed on the Plastigauge envelope, to obtain
the main bearing running clearance (see
illustration). Compare the clearance
measured with that given in the Specifications
at the start of this Chapter.

12 If the clearance is significantly different

from that expected, the bearing shells may be
the wrong size (or excessively worn, if the
original shells are being re-used). Before
deciding that different-size shells are required,
make sure that no dirt or oil was trapped

between the bearing shells and the main
bearing caps or block when the clearance was
measured. If the Plastigauge was wider at one
end than at the other, the crankshaft journal
may be tapered.
13 If the clearance is not as specified, use the
reading obtained, along with the shell

thicknesses quoted above, to calculate the

necessary grade of bearing shells required.
When calculating the bearing clearance
required, bear in mind that it is always better
to have the running clearance towards the
lower end of the specified range, to allow for
wear in use.
14 Where necessary, obtain the required
grades of bearing shell, and repeat the running
clearance checking procedure as described
above.
15 On completion, carefully scrape away all
traces of the Plastigauge material from the
crankshaft and bearing shells. Use your
fingernail, or a wooden or plastic scraper
which is unlikely to score the bearing surfaces.

Final crankshaft refitting

16 Carefully lift the crankshaft out of the
cylinder block once more. On B2O4 and B234

engines, refit the crankshaft position sensor
reluctor if removed, and tighten the screws.

17 Using a little grease, stick the upper
thrustwashers to each side of the centre main
bearing upper location; ensure that the oilway
grooves on each thrustwasher face outwards
(away from the cylinder block)
18 Place the bearing shells in their locations
in the caps as described earlier. If new shells
are being fitted, ensure that all traces of
protective grease are cleaned off, using

Engine removal and general overhaul procedures 2B•23

18.18 Lubricating the main bearing shells

paraffin. Wipe dry the shells and connecting
rods with a lint-free cloth. Liberally lubricate

each bearing shell in the cylinder

block/crankcase with clean engine oil (see
illustration).
19 Lower the crankshaft into position so that
Nos 2 and 3 cylinder crankpins are at TDC. In
this position, Nos 1 and 4 cylinder crankpins
will be at BDC, ready for fitting No 1 piston.
Check the crankshaft endfloat as described in
Section 14.
20 Lubricate the lower bearing shells in the
main bearing caps with clean engine oil. Make
sure that the locating lugs on the shells
engage with the corresponding recesses in the
caps.

21 Fit the main bearing caps to their correct

locations, ensuring that they are fitted the
correct way round (the bearing shell lug
recesses in the block and caps must be on the
same side). Insert the bolts loosely.
22 Progressively tighten the main bearing cap
bolts to the specified torque wrench setting.

23 Check that the crankshaft rotates freely.
24 Refit the piston/connecting rod
assemblies to the crankshaft, as described in
Section 19.
25 Before refitting the crankshaft rear oil seal

housing, fit a new rear oil seal in the housing,
with reference to Chapter 2A. Use a mallet and
block of wood to drive it into the housing, or
alternatively, use the block of wood in a vice
(see illustrations).

26 Apply suitable sealant to the contact faces

18.25a Driving the crankshaft rear oil seal

into the housing

of the rear oil seal housing, then smear a little
oil on the oil seal lips, and refit the locating
dowels where necessary. Locate the housing
on the rear of the cylinder block. To prevent
damage to the oil seal as it locates over the
crankshaft, make up a guide out of a plastic
container, or alternatively use adhesive tape.
Once the housing is in position, remove the
guide or tape, then insert the bolts and tighten

them to the specified torque (see

illustrations).
27 Refit the flywheel/driveplate, oil pick-
up/strainer/transfer tube and sump, with
reference to Part A of this Chapter.
28 Where removed, refit the cylinder head as
described in Part A.

29 Refit the timing chain and sprocket as
described in Part A of this Chapter.

Selection of bearing shells

1 The big-end bearing shells are classified for

thickness as described in Section 15. Note
that up to the second undersize, it is possible
to mix different thicknesses of shell, in order to
obtain the correct running clearance.
Commence the procedure with the two
thinnest shells, then if the clearance is too

18.25b Fitting the crankshaft rear oil seal

using a block of wood in a vice

great, fit one thick shell with one thin shell, and
make the check again. If the clearance is still

too great, fit two thick shells.

Big-end bearing running
clearance check

2 The clearance can be checked in either of
two ways.
3 One method is to refit the big-end bearing
cap to the connecting rod before refitting the
pistons to the cylinder block, ensuring that
they are fitted the correct way round, with the
bearing shells in place. With the cap retaining
nuts correctly tightened, use an internal
micrometer or vernier caliper to measure the
internal diameter of each assembled pair of
bearing shells. If the diameter of each
corresponding crankshaft journal is measured
and then subtracted from the bearing internal
diameter, the result will be the big-end bearing
running clearance.
4 The second, and more accurate, method is
to use Plastigauge (see Section 18) after
refitting the pistons to the cylinder block. The

following paragraphs describe the latter

method, together with the refitting of the
pistons to the cylinder block.
5 Position the cylinder block either on its side
or on the flywheel/driveplate end.
6 Lay out the assembled pistons and rods in

order, with the bearing shells, connecting rod
caps and nuts.
7 Clean the backs of the bearing shells, and
the bearing locations in both the connecting

18.26a Adhesive tape over the end of the

crankshaft will prevent damage to the oil

seal when refitting

18.26b Applying sealant to the rear oil seal

housing

18.26c Refitting the rear oil seal housing

(engine backplate)

2B•24 Engine removal and general overhaul procedures

19.10 Piston ring compressor fitted over

the piston rings

rod and bearing cap. If new shells are being

fitted, ensure that all traces of protective
grease are cleaned off, using paraffin.
8 Press the bearing shells into their locations,
ensuring that the tab on each shell engages in
the notch in the connecting rod and cap. Take
care not to touch any shell's bearing surface

with your fingers. If the original bearing shells
are being used for the check, ensure that they
are refitted in their original locations.
9 Lubricate the cylinder bores, pistons and
piston rings with clean engine oil, then lay out
each piston/connecting rod assembly in its
respective position. Do not lubricate the
bearing shells at this stage.

10 Start with assembly No 1. Make sure that

the piston rings are still spaced as described
in Section 17, then clamp them in position with
a piston ring compressor (see illustration).
11 Insert the piston/connecting rod assembly
into the top of cylinder No 1. Ensure that the
notch or arrow on the piston crown is pointing
towards the timing chain end of the engine.

Using a block of wood or hammer handle

against the piston crown, tap the assembly into
the cylinder bore until the piston crown is flush
with the top of the cylinder (see illustrations).
Make sure that the ends of the big-end bearing
cap bolts do not scratch the bore walls.
12 With the No 1 crankpin at the bottom of its
stroke, guide the connecting rod onto it while
tapping the top of the piston with the hammer
handle.

13 Place a strand of Plastigauge on the

crankpin journal.

14 Refit the big-end bearing cap, using the
marks made or noted on removal to ensure

that they are fitted the correct way round.

19.14 Tightening the big-end bearing cap

nuts

19.11 a The arrow on the piston crown must

point towards the timing chain end of the

engine

Tighten the bearing cap nuts to the specified
torque (see illustration). Take care not to
disturb the Plastigauge or rotate the
crankshaft during the tightening sequence.

15 Dismantle the assembly, then use the

scale printed on the Plastigauge envelope to
obtain the big-end bearing running clearance.

16 If the clearance is significantly different
from that specified, the bearing shells may be
the wrong size (or excessively worn, if the
original shells are being re-used). If necessary,
select different shells as described in
paragraph 1. Make sure that no dirt or oil was
trapped between the bearing shells and the
cap or connecting rod when the clearance was
measured. If the Plastigauge was wider at one
end than at the other, the crankpins may be
tapered.
17 Push the No 1 piston/connecting rod
assembly to the top of the cylinder, then refit
the No 4 piston/connecting rod assembly and
repeat the bearing running clearance check.
With Nos 1 and 4 pistons at the top of their
bores, refit Nos 2 and 3 pistons and repeat the
bearing running clearance check on these.
18 On completion, carefully scrape away all
traces of the Plastigauge material from the
crankshaft and bearing shells. Use your
fingernail, or some other object which is
unlikely to score the bearing surfaces.

Final piston/connecting rod
refitting

19 Position No 1 crankpin at the bottom of its
stroke. Liberally lubricate the crankpin and
both bearing shells. Taking care not to mark

the cylinder bores, tap the piston/connecting
rod assembly down the bore and onto the
crankpin. Refit the big-end bearing cap,
tightening its retaining nuts finger-tight at first.

Note that the faces with the identification
marks must match (which means that the
bearing shell locating tabs abut each other).

20 Tighten the bearing cap retaining nuts
evenly and progressively to the specified
torque setting.
21 Rotate the crankshaft. Check that it turns
freely; some stiffness is to be expected if new
components have been fitted, but there should

be no signs of binding or tight spots.
22 Refit the remaining three piston/
connecting rod assemblies to their crankpins
in the same way.

19.11b Using a hammer handle to tap the

piston down the cylinder bore

23 Refit the oil pump pick-up/strainer, sump
and cylinder head with reference to Part A of
this Chapter.

1 With the engine refitted in the vehicle,
double-check the engine oil and coolant
levels. Make a final check that everything has
been reconnected, and that there are no tools
or rags left in the engine compartment.
2 Remove the spark plugs. On models with a
distributor, disable the ignition system by
disconnecting the ignition HT coil lead from
the distributor cap, and earthing it on the
cylinder block. Use a jumper lead or similar
wire to make a good connection. On models
with Direct Ignition, disconnect the wiring plug

from the ignition cartridge (refer to Chapter 5B

if necessary).

3 Turn the engine on the starter until the oil

pressure warning light goes out. Refit the
spark plugs, and reconnect the coil lead to the
distributor cap or Dl cartridge wiring (as

applicable).
4 Start the engine, noting that this may take a
little longer than usual, due to the fuel system
components having been disturbed.
5 While the engine is idling, check for fuel,
water and oil leaks. Don't be alarmed if there
are some odd smells and smoke from parts
getting hot and burning off oil deposits.
6 Assuming all is well, keep the engine idling
until hot water is felt circulating through the
top hose then switch off the engine.
7 Check the ignition timing and the idle speed
settings (as appropriate), then switch off the
engine.
8 After a few minutes, recheck the oil and
coolant levels as described in Chapter 1, and
top-up as necessary.
9 There is no requirement to re-tighten the
cylinder head bolts once the engine has first
run after reassembly.

10 If new pistons, rings or crankshaft bearings
have been fitted, the engine must be treated as
new, and run-in for the first 500 miles (800 km).

Do not operate the engine at full-throttle, or
allow it to labour at low engine speeds in any
gear. It is recommended that the oil and filter
be changed at the end of this period.