width FORD SIERRA 1991 2.G SOHC Engines Workshop Manual

Crankshaft
Endfloat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.08 to 0.28 mm (0.003 to 0.011 in)
Main bearing running clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.010 to 0.064 mm
Main bearing journal diameter:
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56.970 to 56.990 mm
Undersize 0.25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56.720 to 56.740 mm
Undersize 0.50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56.470 to 56.490 mm
Undersize 0.75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56.220 to 56.240 mm
Undersize 1.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55.970 to 55.990 mm
Main bearing thrustwasher thickness:
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.30 to 2.35 mm
Oversize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.50 to 2.55 mm
Big-end bearing running clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.006 to 0.060 mm
Big-end bearing journal diameter:
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51.980 to 52.000 mm
Undersize 0.25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51.730 to 51.750 mm
Undersize 0.50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51.480 to 51.500 mm
Undersize 0.75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51.230 to 51.250 mm
Undersize 1.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50.980 to 51.000 mm
Pistons and piston rings
Piston diameter:
Standard class 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78.965 to 78.975 mm
Standard class 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78.975 to 78.985 mm
Standard class 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78.985 to 78.995 mm
Standard class 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78.995 to 79.005 mm
Standard service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78.990 to 79.015 mm
Service oversize 0.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79.490 to 79.515 mm
Service oversize 1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79.990 to 80.015 mm
Piston ring end gap:
Top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.300 to 0.500 mm
Centre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.300 to 0.500 mm
Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.400 to 1.400 mm
Auxiliary shaft
Endfloat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.050 to 0.204 mm (0.002 to 0.008 in)
Cylinder head
Valve seat angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44¼ 30Õ to 45¼ 00Õ
Service correction cutter*:
Upper correction angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30¼
Lower correction angle:
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75¼
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62.5¼
Valve seat width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 to 2.0 mm
Valve guide bore:
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.063 to 8.088 mm
Oversize 0.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.263 to 8.288 mm
Oversize 0.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.463 to 8.488 mm
*Not for use with hardened valve seats
Camshaft
Endfloat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.104 to 0.204 mm (0.004 to 0.008 in)
Thrust plate thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.98 to 4.01 mm (0.156 to 0.158 in)
Bearing journal diameter:
Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41.987 to 42.013 mm
Centre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44.607 to 44.633 mm
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44.987 to 45.013 mm
Valves
Valve clearance (cold engine):
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.20 ±0.03 mm (0.008 ±0.001 in)
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.25 ±0.03 mm (0.010 ±0.001 in)
Valve timing:
Inlet opens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22¼ BTDC
Inlet closes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54¼ ABDC
Exhaust opens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64¼ BBDC
Exhaust closes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12¼ ATDC
Valve spring free length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47.00 mm (1.85 in)
2A¥2SOHC engines

components, but there must be no tight spots
or binding.
28Check that the crankshaft endfloat is
within the specified limits by inserting a feeler
blade between the centre crankshaft web and
the thrustwashers.
29Make sure that the rear oil seal is fully
located onto its seating. Coat the rear main
bearing cap sealing wedges with sealing
compound, then press them into position
using a blunt screwdriver with the rounded
red face towards the cap (see illustration).
30Refit the oil pump and pick-up tube.
31Refit the crankshaft front oil seal housing
and the auxiliary shaft front cover using a new
gasket, and tighten the securing bolts. Smear
the lip of the oil seal with clean engine oil
before fitting; and using a straight edge, ensure
that the bottom face of the oil seal housing is
aligned with the bottom face of the cylinder
block before finally tightening the bolts.
32Refit the pistons and connecting rods.
33Refit the flywheel/driveplate and the
auxiliary shaft sprocket, crankshaft sprocket,
and timing belt.
1Examine the bearing surfaces of the
crankshaft for scratches or scoring and, using
a micrometer, check each journal and
crankpin for ovality. Where this is found to be
in excess of 0.0254 mm (0.001 in) the
crankshaft will have to be reground and
undersize bearings fitted.
2Crankshaft regrinding should be carried out
by a suitable engineering works, who will
normally supply the matching undersize main
and big-end shell bearings.
3Note that undersize bearings may already
have been fitted, either in production or by a
previous repairer. Check the markings on the
backs of the old bearing shells, and if in doubt
take them along when buying new ones.
Production undersizes are also indicated by
paint marks as follows:
White line on main bearing cap - parent bore
0.40 mm oversize
Green line on crankshaft front counterweight
- main bearing journals 0.25 mm
undersize
Green spot on counterweight - big-end
bearing journals 0.25 mm undersize4If the crankshaft endfloat is more than the
maximum specified amount, new
thrustwashers should be fitted to the centre
main bearings. These are usually supplied
together with the main and big-end bearings
on a reground crankshaft.
5An accurate method of determining bearing
wear is by the use of Plastigage. The
crankshaft is located in the main bearings
(and big-end bearings if necessary) and the
Plastigage filament located across the journal
which must be dry. The cap is then fitted and
the bolts/nuts tightened to the specified
torque. On removal of the cap the width of the
filaments is checked against a scale which
shows the bearing running clearance. This
clearance is then compared with that given in
the Specifications (see illustration).
6If the spigot bearing in the rear of the
crankshaft requires renewal, extract it with a
suitable puller. Alternatively fill it with heavy
grease and use a close fitting metal dowel
driven into the centre of the bearing. Drive the
new bearing into the crankshaft with a soft
metal drift.
1The cylinder bores must be examined for
taper, ovality, scoring and scratches. Start by
examining the top of the bores; if these are
worn, a slight ridge will be found which marks
the top of the piston ring travel. If the wear is
excessive, the engine will have had a high oil
consumption rate accompanied by blue
smoke from the exhaust.
2If available, use an inside dial gauge to
measure the bore diameter just below the
ridge and compare it with the diameter at the
bottom of the bore, which is not subject to
wear. If the difference is more than 0.152 mm
(0.006 in), the cylinders will normally require
reboring with new oversize pistons fitted.
3Proprietary oil control rings can be obtained
for fitting to the existing pistons if it is felt that
the degree of wear does not justify a rebore.
However, any improvement brought about by
such rings may be short-lived.
4If new pistons or piston rings are to be fitted
to old bores, deglaze the bores with abrasive
paper or a Òglaze busterÓ tool. The object is to
produce a light cross-hatch pattern to assistthe new rings to bed in.
5If there is a ridge at the top of the bore and
new piston rings are being fitted, either the
top piston ring must be stepped (Òridge
dodgerÓ pattern) or the ridge must be
removed with a ridge reamer. If the ridge is
left, the piston ring may hit it and break.
6Thoroughly examine the crankcase and
cylinder block for cracks and damage and use
a piece of wire to probe all oilways and
waterways to ensurethatthey are
unobstructed.
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 bay.
2Check that oil and coolant levels are
correct.
3Start the engine. This may take a little
longer than usual as fuel is pumped up to the
engine.
4Check that the oil pressure light goes out
when the engine starts.
5Run the engine at a fast tickover and check
for leaks of oil, fuel or coolant. Also check
power steering and transmission fluid cooler
unions, where applicable. Some smoke and
odd smells may be experienced as assembly
lubricant burns off the exhaust manifold and
other components.
6Bring the engine to normal operating
temperature, then check the ignition timing
and the idle speed (where applicable) and
mixture.
7If splined type cylinder head bolts have
been used, stop the engine after it has been
running for 15 minutes, then remove the
crankshaft cover and tighten the cylinder
head bolts to the fourth stage given in the
Specifications, in the correct order.
8When the engine has completely cooled,
re-check the oil and coolant levels, and
check, and if necessary adjust, the valve
clearances.
9If 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.
37Initial start-up after overhaul or
major repair
36Cylinder block and bores -
examination and renovation35Crankshaft and bearings -
examination and renovation
2A¥24SOHC engines
34.24 Fitting a thrustwasher to the centre
main bearing cap35.5 Checking the width of the filament
against the scale of the packet34.29 Fitting a sealing wedge to the rear
main bearing cap