|
If the there is lack of power, excessive oil
consumption or poor fuel economy, measure the compression
pressure. |
| 1. |
Warm up and stop engine.
Allow the engine to warm up to normal
operating temperature. |
| 2. |
Remove the surge
tank. |
| 3. |
Remove the ignition coil connectors(A) and
ignition coils(B).
|
| 4. |
Remove the spark plugs.
Using a 16mm plug wrench, remove the 6 spark
plugs. |
| 5. |
Check cylinder compression
pressure.
| (1) |
Insert a compression gauge into the
spark plug hole. |
| (2) |
Fully open the
throttle. |
| (3) |
After 7 times of cranking the engine,
measure the compression pressure.
|
Always use a fully charged
battery to obtain engine speed of 250 rpm or
more. | |
| (4) |
Repeat steps 1) through 3) for each
cylinder.
|
This measurement must be done in
as short a time as
possible. |
Compression pressure
:
1,225kPa (12.5kgf/cm²,
177psi)
Minimum pressure
:
1,078kPa (11.0kgf/cm²,
156psi)
Difference between each
cylinder :
98kPa (1.0kg/cm², 14psi) or less
| |
| (5) |
If the cylinder compression in 1 or
more cylinders is low, pour a small amount of engine oil into
the cylinder through the spark plug hole and repeat steps (1)
through (3) for cylinders with low compression.
| A. |
If adding oil helps the
compression, it is likely that the piston rings and/or
cylinder bore are worn or
damaged. |
| B. |
If pressure stays low, a valve
may be sticking or seating is improper, or there may be
leakage past the
gasket. | | |
| 6. |
Reinstall the spark
plugs. |
| 7. |
Install the ignition coil and ignition coil
connectors. |
| 8. |
Install the surge
tank. |
Valve
Clearance Inspection And Adjustment
|
Inspect and adjust the valve clearance when
the engine is cold (Engine coolant temperature : 20°C) and cylinder
head is installed on the cylinder
block. |
| 1. |
Remove the engine
cover. |
| 2. |
Remove air cleaner
assembly. |
| 3. |
Remove the surge
tank. |
| 4. |
Remove the cylinder head cover.
| (1) |
Disconnect the ignition coil connector
and remove the ignition coil. |
| (2) |
Disconnect the breather pipe
assembly(A) from the intake manifold.
|
| (3) |
Loosen the cylinder head cover bolts
and then remove the cover(A) and gasket.
| |
| 5. |
Set No.1 cylinder to
TDC/compression.
| (1) |
Turn the crankshaft pulley and align
its groove with the timing mark "T" of the lower timing chain
cover.
|
| (2) |
Check that the mark(A) of the camshaft
timing sprockets are in straight line on the cylinder head
surface as shown in the illustration.
If not, turn the crankshaft one
revolution (360°)
|
Do not rotate engine
counterclockwise |
| |
| 6. |
Inspect the valve clearance.
| (1) |
Check only the valve indicated as
shown. [No. 1 cylinder : TDC/Compression] measure the valve
clearance.
Measurement method.
| A. |
· Using a thickness gauge,
measure the clearance between the tappet and the base
circle of camshaft.
· Record the
out-of-specification valve clearance measurements. They
will be used later to determine the required replacement
adjusting tappet.
Valve
clearance
Specification
Engine coolant temperature
: 20°C [68°F]
Limit
Intake : 0.17 ~ 0.23mm
(0.0067 ~ 0.0090in.)
Exhaust : 0.27 ~ 0.33mm
(0.0106 ~ 0.0129in.)
| | |
| (2) |
Turn the crankshaft pulley one
revolution (360°) and align the groove with timing mark "T" of
the lower timing chain cover.
|
Do not rotate engine
counterclockwise | |
| (3) |
Check only valves indicated as shown.
[NO. 4 cylinder : TDC/compression]. Measure the valve
clearance. (Refer to procedure step1))
| |
| 7. |
Adjust the intake and exhaust valve
clearance.
| (1) |
Set the No.1 cylinder to the
TDC/compression. |
| (2) |
Remove the timing chain.
|
Before removing the timing
chain, mark the RH/LH timing chain with an
identification based on the location of the sproket
because the identification mark on the chain for TDC(Top
Dead Center) can be
erased. | |
| (3) |
Remove the camshaft bearing
caps(A).
|
| (4) |
Remove the camshaft
assembly(A).
|
| (6) |
Measure the thickness of the removed
tappet using a micrometer.
|
| (7) |
Calculate the thickness of a new
tappet so that the valve clearance comes within the specified
value.
Valve
clearance
(Engine coolant temperature:
20°C[68°F])
T : Thickness of removed
tappet
A : Measured valve
clearance
N : Thickness of new
tappet
Intake : N = T + [A -
0.20mm(0.0079in.)]
Exhaust : N = T + [A - 0.30mm
(0.0118in.)]
| |
| (8) |
Select a new tappet with a thickness
as close as possible to the calculated value.
|
Shims are available in 41size
increments of 0.015mm (0.0006in.) from 3.00mm (0.118in.)
to 3.600mm
(0.1417in.) | |
| (9) |
Place a new tappet on the cylinder
head.
|
Apply engine oil at the selected
tappet on the periphery and top
surface. | |
| (10) |
Install the intake and exhaust
camshaft. |
| (11) |
Install the bearing caps(Refer to
Cylinder head assembly in this
Group). |
| (12) |
Install the timing chain(Refer to
Timing system in this Group). |
| (13) |
Turn the crankshaft two turns in the
operating direction(clockwise) and realign crankshaft sprocket
and camshaft sprocket timing marks(A).
|
| (14) |
Recheck the valve
clearance.
Valve
clearance
(Engine coolant temperature:
20°C[68°F]
[Specification]
Intake : 0.17 ~ 0.23mm (0.0067 ~
0.0090in.)
Exhaust : 0.27 ~ 0.33mm (0.0106
~ 0.0129in.)
| | |
