maintenance FORD SIERRA 1991 2.G DOHC Engine Workshop Manual

General
Engine type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Four-cylinder, in-line, double overhead camshaft
Engine code:
Carburettor engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N8A
Fuel injection engine without catalyst . . . . . . . . . . . . . . . . . . . . . . . . . N9A
Fuel injection engine with catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . N9C
Bore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.00 mm
Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.00 mm
Cubic capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1998 cc
Compression ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 : 1
Compression pressure at starter motor speed . . . . . . . . . . . . . . . . . . . . 11 to 13 bars
Maximum continuous engine speed:
N8A engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6050 rpm
All engines except N8A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5950 rpm
Maximum engine power (DIN):
N8A engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 kW at 5600 rpm
N9A engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 kW at 5500 rpm
N9C engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 kW at 5500 rpm
Maximum engine torque:
N8A engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 Nm at 3000 rpm
N9A engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 Nm at 2500 rpm
N9C engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Nm at 2500 rpm
Cylinder bore diameter
Standard class 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.000 to 86.010 mm
Standard class 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.010 to 86.020 mm
Oversize 0.15 class A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.150 to 86.160 mm
Oversize 0.15 class B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.160 to 86.170 mm
Oversize 0.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.500 to 86.510 mm
Chapter 2 Part B:
DOHC engine
Camshafts and cam followers - removal, inspection and refitting . . .21
Crankcase ventilation system - inspection and maintenance . . . . . . .2
Crankshaft and bearings - examination and renovation . . . . . . . . . .31
Crankshaft and main bearings - removal and refitting . . . . . . . . . . . .30
Crankshaft front oil seal - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Crankshaft rear oil seal - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Cylinder head - dismantling and reassembly . . . . . . . . . . . . . . . . . . .19
Cylinder head - inspection and renovation . . . . . . . . . . . . . . . . . . . . .20
Cylinder head - removal and refitting (engine in vehicle) . . . . . . . . . .17
Cylinder head - removal and refitting (engine removed) . . . . . . . . . . .18
Engine/automatic transmission assembly - removal and separation . .8
Engine/automatic transmission assembly - reconnection and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Engine dismantling, examination, renovation and reassembly - general
information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Engine/manual gearbox assembly - removal and separation . . . . . . .7
Engine/manual gearbox assembly - reconnection and refitting . . . . .11Engine - refitting (manual gearbox in vehicle) . . . . . . . . . . . . . . . . . . . .9
Engine - refitting (automatic transmission in vehicle) . . . . . . . . . . . . .10
Engine - removal leaving manual gearbox in vehicle . . . . . . . . . . . . . .5
Engine - removal leaving automatic transmission in vehicle . . . . . . . .6
Engine mountings - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Flywheel/driveplate - removal, inspection and refitting . . . . . . . . . . .22
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Initial start-up after overhaul or major repair . . . . . . . . . . . . . . . . . . .32
Major operations possible with the engine in the vehicle . . . . . . . . . . .3
Major operations requiring engine removal . . . . . . . . . . . . . . . . . . . . .4
Oil pump drive chain and sprockets - examination and renovation . .28
Oil pump - dismantling, inspection and reassembly . . . . . . . . . . . . .27
Oil pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Pistons and connecting rods - removal and refitting . . . . . . . . . . . . .29
Sump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Timing chain and sprockets - removal and refitting . . . . . . . . . . . . . .15
Timing chain, sprockets and tensioner - examination and renovation .16
2B•1
Specifications Contents
2B
Unless otherwise stated, procedures are as described for the SOHC engines in Part A of this Chapter.
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty

Torque wrench settingsNmlbf ft
Main bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 to 10466 to 77
Connecting rod (big-end bearing cap) bolts:
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 to 84 to 6
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 to 1711 to 13
Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle-tighten a further 85º
Crankshaft pulley bolt:
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 to 5833 to 43
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle-tighten a further 80º
Camshaft sprocket bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 to 6341 to 46
Flywheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82 to 9261 to 68
Oil pump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 to 127 to 9
Oil pump sprocket bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 to 1912 to 14
Oil pump chain tensioner bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 to 137 to 10
Sump bolts and nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 106 to 7
Sump studs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 to 84 to 6
Sump drain plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2815 to 21
Sump front mounting plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 to 2817 to 21
Oil baffle nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 to 2113 to 15
Oil pick-up pipe-to-cylinder block bolts . . . . . . . . . . . . . . . . . . . . . . . . .9 to 137 to 10
Oil pressure warning lamp switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 to 2213 to 16
Cylinder head bolts:
M11 bolts:
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4030
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5541
Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle-tighten a further 90º
Stage 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Angle-tighten a further 90º
M8 bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 to 3927 to 29
Camshaft cover bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 to 84 to 6
Camshaft bearing cap nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 to 2616 to 19
Lower timing chain guide upper bolt . . . . . . . . . . . . . . . . . . . . . . . . . . .10 to 137 to 10
Lower timing chain guide lower bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 to 2818 to 21
Upper and lower timing chain cover bolts . . . . . . . . . . . . . . . . . . . . . . .7 to 105 to 7
Crankshaft rear oil seal housing bolts . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 116 to 8
Engine-to-gearbox/transmission bolts . . . . . . . . . . . . . . . . . . . . . . . . . .29 to 4121 to 30
The 2.0 litre DOHC (Double OverHead
Camshaft) engine was introduced in August
1989 to replace the 2.0 litre SOHC engine
used previously in the Sierra range. The
engine is of four-cylinder, in-line type.
The crankshaft incorporates five main
bearings. Thrustwashers are fitted to the
centre main bearing in order to control
crankshaft endfloat.
The camshafts are driven by a chain from
the crankshaft, and operate the angled valves
via hydraulic cam followers. One camshaft
operates the inlet valves, and the other
operates the exhaust valves. The operation of
the cam followers is explained in Chapter 2,
Part C, but note that no rollers are fitted and
the base of each cam follower is in direct
contact with the cam profile.
The distributor is driven directly from the
front of the inlet camshaft, and the oil pump is
driven by a chain from the crankshaft. An
electric fuel pump is mounted in the fuel tank.Lubrication is by means of a bi-rotor pump
which draws oil through a strainer located
inside the sump, and forces it through a full-
flow filter into the engine oil galleries, from
where it is distributed to the crankshaft and
camshafts. The big-end bearings are supplied
with oil via internal drillings in the crankshaft.
The undersides of the pistons are supplied
with oil from drillings in the connecting rods.
The hydraulic cam followers are supplied with
oil from passages in the cylinder head. The
camshafts are lubricated by oil from spray
tubes mounted above the camshaft bearing
caps.
A closed crankcase ventilation system is
employed, whereby piston blow-by gases are
drawn from the crankcase, through a breather
pipe into the inlet manifold, where they are
burnt with fresh air/fuel mixture.
Refer to Chapter 1, Section 35.The following operations can be carried out
without removing the engine from the vehicle:
a)Removal of the camshafts.
b)Removal and servicing of the cylinder head
c)Removal of the timing chain and
sprockets.
d)Removal of the oil pump.
e)Removal of the sump.
f)Removal of the pistons and connecting
rods.
g)Removal of the big-end bearings.
h)Removal of the engine mountings
i)Removal of the clutch and flywheel.
j)Removal of the crankshaft front and rear
oil seals.
The following operation can only be carried out
after removing the engine from the vehicle:
a)Removal of the crankshaft and main
bearings.
4Major operations requiring
engine removal
3Major operations possible with
the engine in the vehicle
2Crankcase ventilation system -
inspection and maintenance
1General information
DOHC engine 2B•3
2B