2003 DAEWOO MATIZ camshaf

GENERAL ENGINE INFORMATION 1A–9
DAEWOO M-150 BL2
GENERAL DIAGNOSIS (Cont’d)
 Condition Probable cause Correction
Poor FuelMalfunction of
Improper ignition timing.
Adjust the ignition timing.
ConsumptionIgnition System
Abnormal spark plug
(Excessive carbon deposit,
inadequate gap, burnt
electrode).
Replace the plug.

Electric leakage or poor
connection of the high
tension cable.
Connect the cable normally
or replace it.
Malfunction of
Cooling System
Malfunction of the
thermostat.
Replace the thermostat.
Others
Improperly installed valve.
Repair or replace the valve.

Slipping clutch.
Repair or replace the clutch.

Low pressure of tires.
Adjust the pressure of tires.
ExcessiveLeakage of
Loosened oil drain plug.
Tighten the plug.
Consumption of
Engine OilEngine Oil
Loosened oil pan bolt.
Tighten the bolt.Engine Oil

Loosened oil filter.
Tighten the filter.

Loosened oil pressure
switch.
Tighten the switch.

Leakage of camshaft front oil
seal.
Replace the seal.

Leakage of crankshaft front
oil seal.
Replace the seal.

Leakage at the cylinder head
cover gasket.
Replace the gasket.

Damage of the cylinder head
gasket.
Replace the gasket.
Oil Mixing in
Combustion
Stuck piston ring.
Remove carbon and replace
the ring.
Chamber
Worn piston or cylinder.
Replace the piston or the
cylinder.

Worn piston ring or ring
groove.
Replace the piston or ring.

Inadequate position of the
piston ring cutting part.
Adjust the position.

Abrasion or damage of the
valve system.
Replace the valve system.
Low Oil PressureMalfunction of
Lubrication
Inadequate oil viscosity.
Replace with the specified
one.
System
Loosening of the oil pressure
switch.
Tighten the switch.

Lack of engine oil.
Refill oil.

Blocking oil strainer.
Clean the strainer.

1B – 2 SOHC ENGINE MECANICAL
DAEWOO M-150 BL2
DESCRIPTION AND OPERATION
ENGINE TYPE
The engine is 4-cycle, water-cooled, in-line 3 cylinders
with displacement of 796cc (68.5×72.0mm) (2.70×
2.83 in.).
Engine model
(Specifications)F8C Type SOHC /
2 Valve (MPI)
Maximum power (kw/rpm)37.5 / 6,000
Maximum torque (N
m/rpm)68.6 / 4,600
Compression ratio9.3 : 1
D102B001
ENGINE LUBRICATION
The engine lubrication is of the wetsump method to draw
up the oil forced by the oil pump. The oil pump is of a
trochoid type, and mounted on crankshaft at crankshaft
pulley side (a). Oil is drawn up through oil pump pickup
tube (b) and passed through pump (c) to oil filter (d). The
filtered oil flows into two paths in engine block. In one
path (e), oil reaches crankshaft journal bearings. Oil
from crankshaft journal bearings is supplied to connect-
ing rod bearings by means of intersecting passages
drilled in crankshaft, and then injected from a small hole
provided on big end of connecting rod to lubricate piston
(f), rings, and cylinder wall. In another path (g), oil goes
up to cylinder head and lubricates rocker arm (i), valve
(j), camshaft (k), etc. through the oil hole provided on the
rocker arm shaft (h).
D102B002
CYLINDER HEAD AND VALVE TRAIN
The cylinder head is made of cast aluminum alloy for
better strength in hardness with lightweight, and cam-
shaft (k) and rocker arm shaft (h) arranged in-line sup-
port.
D102B003
The combustion chambers are formed into the manifold
combustion chambers with increased squish parts for
better combustion efficiency and its intake and exhaust

SOHC ENGINE MECANICAL 1B–3
DAEWOO M-150 BL2
parts are installed in the cross flow arrangement. The
rocker arm (i) operates in seesaw motion to close and
open the intake and exhaust valves (j) with camshaft by
turning the rocker arm shaft of each intake and exhaust
part.
ENGINE BLOCK
As the largest part of the engine components. the block
(l) has all the necessary parts attached to outer surface
of it.
On the inside surface of block, there are bore surfaces
by horning, which are cylinders, and on the periphery of
the cylinders, there are the passages to prevent the
over-heated and to lubricate the engine block.
CRANKSHAFT
The crankshaft (m) is to convert the rectilinear motion
into the rotation motion through the connecting rod (n)
which transmits the power generated by combustion.
On the one side of it, oil pump, crankshaft pulley and
timing belt pulley are attached, and oil seal housing and
flywheel are on the other side.
A special steel of high grade cast iron is used for the ma-
terial to stand the bending load and distortion. The mate-
rial of the main bearing (o) is aluminum alloy. The split
thrust bearings (p) are inserted in the journal bearing
part (No.3).
D102B004
CONNECTING ROD
The connecting rods (n) are made of forged steel, and
its section is typed “I” with its big end connected tocrankshaft (m) and its small end to piston pin to transmit
the power.
The big end is detachable, and its upper and lower parts
are fastened by bolting after the metal bearings (q) are
inserted.
PISTON, PISTON RING AND PISTON
PIN
Piston
The piston (r) is of the open skirt type and its crown is
exposed in the combustion chamber to generate power.
Its land and skirt parts are made of coat aluminum alloy
which is light and has excellent heat conductivity in order
to meet its continuous and high speed reciprocation
movement.
Piston Ring
It is composed of two compression rings (s) and one oil
ring (t) and installed between the grooves of the piston
to make the high speed reciprocating movement main-
taining a remarkable air tightness as well as cylinders. It
is a critical parts to affect the compression pressure, oil
consumption, compression, blow by pressure and en-
gine performance.
Piston Pin
The pin (u) is not fixed to the piston or connecting rod
and its both ends are assembled by the circlip (v) in the
full floating type. The pin is used to transmit the power
from the crown part of piston to connecting rod.
D102B005

1B –4 SOHC ENGINE MECANICAL
DAEWOO M-150 BL2
TIMING BELT AND PULLEY
The timing belt connects the camshaft timing pulley (w)
and the crankshaft timing pulley (x). The timing belt
coordinates the crankshaft and the camshaft and keeps
them synchronized. The timing belt also turns the cool-
ant pump (y). The timing belt and the pulleys are toothed
so that there is no slippage between them. There is a
tension pulley (z) that maintains the correct timing belt
tension. The timing belt is made of a tough reinforced
rubber similar to that used on the serpentine drive belt.
The timing belt requires no lubrication.
D102B006
ENGINE MOUNT
This is to absorb or reduce the engine vibration and im-
pact from the wheeled road. Engine mount is attached to
the engine–front side, the engine-right side and the en-
gine-rear side and one transaxle mount is attached to
the transaxle side.
D102B007
D102B008

SOHC ENGINE MECANICAL 1B–5
DAEWOO M-150 BL2
COMPONENT LOCATOR
CYLINDER HEAD
D12B4011
1 Oil Filler Cap
2 Cylinder Head Cover
3 Cylinder Head Cover (Euro III)
4 Distributor Case
5 Camshaft
6 Exhaust Rocker Arm7 Cylinder Head Gasket
8 Cylinder Head
9 Intake Rocker Arm
10 Exhaust Valve
11 Intake Valve

1B –10 SOHC ENGINE MECANICAL
DAEWOO M-150 BL2
ADJUSTMENT OF VALVE
CLEARANCE
Adjust the valve clearance in the following procedures:
1. Remove the air filter/resonator assembly and the
relevant parts installed on the cylinder head cover.
2. Remove the cylinder head cover hexagon bolts and
remove the cover.
3. Turn over the crankshaft to make No.1 cylinder
matched with the compression top dead center.
(When the camshaft sprocket notch (d) is aligned with
the timing belt rear cover triangle pointer (e) and the
crankshaft sprocket point (f) is aligned with the oil
pump housing point (g), the compression top dead
center is on the ignition sequence for No. 1 cylinder.)
D102B303
4. Check the valve clearance for No. 1 cylinder com-
pression top dead center.

Condition

Cylinder
No.

1

2

3

Compression topIntake
dead center of
No.1 cylinder
Exhaust

marks indicates the place where the valve clear-
ance can be checked and adjusted.
5. If the checking for the valve clearance of No.1 cylin-
der compression top dead center is over, position
No.1 cylinder on the exhaust top dead center as rotat-
ing the crankshaft in a 360–degree arc. (When the
camshaft sprocket point (h) is aligned with the timing
belt rear cover triangle pointer (e), the exhaust top
dead center is on the ignition sequence for No. 1 cyl-
inder.)
D102B304
6. Check the valve clearance for the No. 1 cylinder ex-
haust top dead center.

Condition

Cylinder
No.

1

2

3

Exhaust top deadIntake
center of No.1
cylinder
Exhaust

marks indicates the place where the valve clear-
ance can be checked and adjusted.
Check and adjust the valve clearance (i) using thick-
ness gauge (j).
D102B305
D102B306

1B –12 SOHC ENGINE MECANICAL
DAEWOO M-150 BL2
D102B310
5. If the ignition timing exceeds the specified value,
loosen the distributor bolts and adjust it to the speci-
fied ignition timing by turning the distributor body (s).
D102B311
VA LV E T I M I N G C H E C K A N D
ADJUSTMENT
Check the valve timing in the following procedures:
1. After removing the high headlamp, loosen the bolts
(a) and remove the timing belt front upper cover (b).
D102B312
2. Turning the crankshaft clockwise twice, align the
notch (d) on the crankshaft pulley (c) with the mark 0
(e) for the timing check on the timing belt front lower
cover.
D102B313
3. Check if the notch (f) on the camshaft sprocket is
aligned with the triangle pointer (g) on the timing belt
rear cover.
Important: Notch (f) should be aligned with pointer (g)
to set the valve timing normally.
D102B314

SOHC ENGINE MECANICAL 1B–13
DAEWOO M-150 BL2
Adjust the valve timing in the following procedures:
1. Loosen the bolt and remove the timing belt pulley (c).
In loosening the bolt, use the driver (h) in the picture
shown.
D102B315
2. Remove the oil level gauge guide tube (i) and the tim-
ing belt front lower cover (j).
D102B316
3. Remove the timing belt tensioner (k) and the timing
belt (l).
D102B317
4. Using the bolt, turn the crankshaft clockwise to align
the mark (m) on the crankshaft sprocket with the
pointer (n) on the oil pump housing. Then, turn the
camshaft to align the notch (f) with the pointer (g).
D102B318
5. Install the timing belt (l) and the tensioner (k). (Do not
tighten the tensioner bolt completely.)
Turning the crankshaft clockwise twice, align the
mark (m) with the pointer (n) and tighten the tensioner
bolt to 15–23 N
m (11–17 lb-ft).
D12B319A
6. Install all removed parts.