
ME(H4SO)-65
MECHANICAL
Cylinder Head
(5) Compress the valve spring, and then fit the
valve spring retainer key.
(6) After installing, tap the valve spring retainers
lightly with plastic hammer for better seating.
E: INSPECTION
1. VALVE SPRING
1) Check the valve springs for damage, free length,
and tension. Replace the valve spring if it is not
within the standard value presented in the table.
2) To measure the squareness of valve spring,
stand the spring on a surface plate and measure its
deflection at the top using a try square.
2. INTAKE AND EXHAUST VALVE OIL
SEAL
In the following case, pinch and remove the oil seal
from valve using pliers, and then replace it with a
new one.
When the lip is damaged.
When the spring is out of the specified position. When readjusting the surfaces of intake valve
and valve sheet.
When replacing the intake valve guide.
1) Place the cylinder head on ST1.
2) Using ST2, press-fit the oil seal.
CAUTION:
Apply engine oil to oil seal before press-fit-
ting.
When press-fitting oil seal, do not use ham-
mer or strike in.
Differentiate between intake valve oil seal
and exhaust valve oil seal by noting their differ-
ence in color.
ST1 498267800 CYLINDER HEAD TABLE
ST2 498857100 VALVE OIL SEAL GUIDE
Color of rubber part:
Intake [Black]
Exhaust [Brown]
Color of spring part:
Intake [Silver]
Exhaust [Silver]
F: ADJUSTMENT
1. CYLINDER HEAD
1) Make sure that no crack or other damage exists.
In addition to visual inspection, inspect important
areas by means of red lead check.
Also make sure that gasket installing surface
shows no trace of gas and water leaks.
2) Place the cylinder head on ST.
ST 498267800 CYLINDER HEAD TABLE
3) Measure the warping of the cylinder head sur-
face that mates with crankcase using a straight
edge and thickness gauge.
If the warping exceeds the limit, regrind the surface
with a surface grinder.
Warping limit:
0.05 mm (0.0020 in)
Grinding limit:
0.1 mm (0.004 in)
Standard height of cylinder head:
97.5 mm (3.839 in)
(A) Retainer
(B) Valve spring
Free length 54.30 mm (2.1378 in)
Squareness 2.5°, 2.4 mm (0.094 in)
Tension/spring
height215 — 246 N
(21.9 — 25.1 kgf, 48.2 — 55.3 lb)/
45.0 mm (1.772 in)
527 — 582 N
(53.7 — 59.3 kgf, 118.1 — 130.8 lb)/
34.7 mm (1.366 in)
ME-00282
(B)(B)
(A)
ME-00283
ME-00284
ST1
ST2

ME(H4SO)-67
MECHANICAL
Cylinder Head
(2) Insert the ST2 into valve guide and press it
down to remove valve guide.
ST1 498267800 CYLINDER HEAD TABLE
ST2 499767200 VALVE GUIDE REMOVER
(3) Turn the cylinder head upside down and
place ST as shown in the figure.
Intake side:
ST 499767700 VALVE GUIDE ADJUSTER
Exhaust side:
ST 499767800 VALVE GUIDE ADJUSTER
(4) Before installing new oversize valve guide,
make sure that neither scratches nor damages
exist on the inside surface of valve guide holes
in cylinder head.
(5) Put new valve guide, coated with sufficient
oil, in the cylinder, and then insert the ST1 into
valve guide. Press in until the valve guide upper
end is flush with the upper surface of ST2.ST1 499767200 VALVE GUIDE REMOVER
Intake side:
ST2 499767700 VALVE GUIDE ADJUSTER
Exhaust side:
ST2 499767800 VALVE GUIDE ADJUSTER
(6) Check the valve guide protrusion.
Valve guide protrusion: L
Intake
20.0 — 20.5 mm (0.787 — 0.807 in)
Exhaust
16.5 — 17.0 mm (0.650 — 0.669 in)
(7) Ream the inside of valve guide with ST.
Gently rotate the reamer clockwise while press-
ing it lightly into valve guide, and return it also ro-
tating clockwise. After reaming, clean the valve
guide to remove chips.
CAUTION:
Apply engine oil to the reamer when reaming.
If the inner surface of the valve guide is torn,
the edge of the reamer should be slightly
ground with an oil stone.
If the inner surface of the valve guide be-
comes lustrous and the reamer does not chips,
use a new reamer or remedy the reamer.
(A) Valve guide
ME-00290
ST2
ST1
(A)
ME-00291
ST
(A) Valve guide
ST2
ME-00292
ST1
ME-00293(A)L

ME(H4SO)-86
MECHANICAL
Cylinder Block
NOTE:
Immediately after reboring, the cylinder diameter
may differ from its real diameter due to temperature
rise. Thus, pay attention to this when measuring
the cylinder diameter.
Limit of cylinder enlarging (boring):
0.5 mm (0.020 in)
3. PISTON AND PISTON PIN
1) Check the pistons and piston pins for damage,
cracks, and wear and the piston ring grooves for
wear and damage. Replace if defective.
2) Measure the piston-to-cylinder clearance at
each cylinder.
any of the clearances is not to specification, re-
place the piston or bore the cylinder to use an over-
size piston.
3) Make the sure that piston pin can be inserted
into piston pin hole with a thumb at 20°C (68°F).
Replace if defective.
Standard clearance between piston pin and
hole in piston:
Standard
0.004 — 0.008 mm (0.0002 — 0.0003 in)
Limit
0.020 mm (0.0008 in)4) Check the circlip installation groove (A) on piston
for burr. If necessary, remove the burr from groove
so that piston pin can lightly move.
5) Check the piston pin circlip for distortion, cracks
and wear.
4. PISTON RING
1) If the piston ring is broken, damaged, or worn, or
if its tension is insufficient, or when the piston is re-
placed, replace the piston ring with a new one of
the same size as the piston.
CAUTION:
Marks are shown on the end of top and sec-
ond rings. When installing the rings to piston,
face these marks upward.
Oil ring is composed of upper rail, expander
and lower rail. Be careful of the rail direction
when installing oil ring to the piston.
ME-00173
ME-00174
(A) Upper rail
(B) Expander
(C) Lower rail
ME-00175
(A)
ME-00375(A)
(B)
(C)
(A)
(B)
(C)

ME(H4SO)-96
MECHANICAL
Engine Noise
23.Engine Noise
A: INSPECTION
NOTE*:
When disconnecting fuel injector connector, the malfunction indicator light illuminates and DTC is stored in ECM memory.
Therefore, carry out the clear memory mode
Regular clicking soundSound increases as engine
speed increases. Valve mechanism is defective.
Incorrect valve clearance
Worn valve rocker
Worn camshaft
Broken valve spring
Heavy and dull clankOil pressure is low. Worn crankshaft main bearing
Worn connecting rod bearing (big end)
Oil pressure is normal. Loose flywheel mounting bolts
Damaged engine mounting
High-pitched clank (Spark
knock)Sound is noticeable when
accelerating with an overload. Ignition timing advanced
Accumulation of carbon inside combustion chamber
Wrong spark plug
Improper gasoline
Clank when engine speed is
medium (1,000 to 2,000 rpm).Sound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*) Worn crankshaft main bearing
Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warmSound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*) Worn cylinder liner and piston ring
Broken or stuck piston ring
Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is dis-
connected in turn. (NOTE*) Unusually worn valve lifter
Worn cam gear
Worn camshaft journal bore in crankcase
Squeaky sound — Insufficient generator lubrication
Rubbing sound — Defective generator brush and rotor contact
Gear scream when starting
engine— Defective ignition starter switch
Worn gear and starter pinion
Sound like polishing glass with
a dry cloth— Loose drive belt
Defective water pump shaft
Hissing sound — Loss of compression
Air leakage in air intake system, hoses, connections or mani-
folds
Timing belt noise — Loose timing belt
Belt contacting case/adjacent part
Valve tappet noise — Incorrect valve clearance

LU(H4SO)-2
LUBRICATION
General Description
1. General Description
A: SPECIFICATION
Lubrication methodForced lubrication
Oil pumpPump type Trochoid type
Number of teethInner rotor 9
Outer rotor 10
Outer rotor diameter×thicknessNon-turbo model 78×7 mm (3.07×0.28 in)
Turbo model 78×10 mm (3.07×0.39 in)
Tip clearance between inner and outer rotorStandard 0.04 — 0.14 mm (0.0016 — 0.0055 in)
Limit 0.18 mm (0.0071 in)
Side clearance between inner rotor and pump
caseStandard 0.02 — 0.07 mm (0.0008 — 0.0028 in)
Limit 0.12 mm (0.0047 in)
Case clearance between outer rotor and pump
caseStandard 0.10 — 0.175 mm (0.0039 — 0.0069 in)
Limit 0.20 mm (0.0079 in)
Capacity at
80°C (176°F)Non-turbo
model
600 rpmDischarge
pressure98 kPa (1.0 kg/cm
2, 14 psi)
Discharge
quantity3.22 (3.4 US qt, 2.8 Imp qt)/min.
5,000 rpmDischarge
pressure294 kPa (3.0 kg/cm
2, 43 psi)
Discharge
quantity32.62 (34.4 US qt, 28.7 Imp qt)/min.
Turbo model
600 rpmDischarge
pressure98 kPa (1.0 kg/cm
2, 14 psi)
Discharge
quantity4.62 (4.9 US qt, 4.0 Imp qt)/min.
5,000 rpmDischarge
pressure294 kPa (3.0 kg/cm
2, 43 psi)
Discharge
quantity47.02 (49.7 US qt, 41.4 Imp qt)/min.
Relief valve operation pressureNon-turbo model
490 kPa (5.0 kg/cm
2, 71 psi)
Turbo model
588 kPa (6.0 kg/cm
2, 85 psi)
Oil filterTy p eFull-flow filter type
Filtration areaNon-turbo
760 cm
2 (118 sq in)
Tu r b o
800 cm
2 (124 sq in)
By-pass valve opening pressureNon-turbo
157 kPa (1.60 kg/cm
2, 22.8 psi)
Tu r b o
160 kPa (1.63 kg/cm
2, 23.2 psi)
Outer diameter×widthNon-turbo 80×70 mm (3.15×2.76 in)
Tu r b o 6 8×65 mm (2.68×2.56 in)
Oil filter to engine thread size M 20×1.5
Oil pressure
switchType Immersed contact point type
Working voltage — wattage 12 V — 3.4 W or less
Warning light activation pressure
14.7 kPa (0.15 kg/cm
2, 2.1 psi)
Proof pressure
More than 981 kPa (10 kg/cm
2, 142 psi)
Oil capacity (at replacement) 4.02 (4.2 US qt, 3.5 Imp qt)

LU(H4SO)-8
LUBRICATION
Oil Pressure System
2. Oil Pressure System
A: WIRING DIAGRAM
LU-00102
E
i12
i10
i3
B38
B9
A3
B22
E3
14
E11
A:
B:
B:
i10
123456789101112131415161718192021222324252627282930219
32
1234 5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
i3B22
125678
131415169101112
34
17181920
**: 5
: 14
No.14SBF-4SBF-1
B72
14
B72i12
12345678910111213143412
TURBO MODEL NON-TURBO MODELBATTERY
IGNITION
SWITCH
COMBINATION
METER
OIL PRESSURE
WARNING LIGHT
OIL PRESSURE
SWITCH

LU(H4SO)-9
LUBRICATION
Oil Pressure System
B: INSPECTION
Step Check Yes No
1 CHECK COMBINATION METER.
1) Turn the ignition switch to ON. (engine
OFF)
2) Check other warning lights.Does the warning lights illumi-
nate?Go to step 2.Repair or replace
the combination
meter.
Combination
Meter System.>
2 CHECK HARNESS CONNECTOR BETWEEN
COMBINATION METER AND OIL PRES-
SURE SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from oil pressure
switch.
3) Turn the ignition switch to ON.
4) Measure the voltage of harness between
the combination meter connector and chassis
ground.
Connector & terminal
(E11) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Replace the oil
pressure switch.Go to step 3.
3 CHECK COMBINATION METER.
1) Turn the ignition switch to OFF.
2) Remove the combination meter.
3) Measure the resistance of combination
meter.
Te r m i n a l
No. B9 — No. A3:Is the resistance less than 10
Ω?Replace the har-
ness connector
between combina-
tion meter and oil
pressure switch.Repair or replace
the combination
meter and the oil
pressure switch
warning light bulb.

LU(H4SO)-24
LUBRICATION
Engine Lubrication System Trouble in General
9. Engine Lubrication System Trouble in General
A: INSPECTION
Before performing diagnostics, make sure that the engine oil level is correct and no oil leakage exists.
Trouble Possible cause Corrective action
1. Warning light remains
on.1) Oil pressure switch
failureCracked diaphragm or oil leakage within switch Replace.
Broken spring or seized contacts Replace.
2) Low oil pressureClogged oil filter Replace.
Malfunction of oil by-pass valve of oil filter Clean or replace.
Malfunction of oil relief valve of oil pump Clean or replace.
Clogged oil passage Clean.
Excessive tip clearance and side clearance of oil
pump rotor and gearReplace.
Clogged oil strainer or broken pipe Clean or replace.
3) No oil pressureInsufficient engine oil Replenish.
Broken pipe of oil strainer Replace.
Stuck oil pump rotor Replace.
2. Warning light does
not go on.1) Malfunction of combination meter Replace.
2) Poor contact of switch contact points Replace.
3) Disconnection of wiring Repair.
3. Warning light flickers
momentarily.1) Poor contact at terminals Repair.
2) Defective wiring harness Repair.
3) Low oil pressureCheck for the same
possible causes as
listed in 1. — 2).