Mazda 626 1981 Instruction manual

II
-

LOC.
PART
NO.
DESC.
QTY
.
ORD.
•
.
'
.>\..1
ti
1
•.
11\BZDB
6
Y
9i-95-01YB-81
P74
I
/ 5
I
o.
'rY.
b 26 1
I
3 1/ 8
'i
SHIP
1
4
114.1.
INV
.
LINE
INV
.
NO
.
~
NV
.
DATE
DLR.
CODE

JACK-UP
AND
SUPPORT LOCATIONS
FRONT
REAR
Note:
After jacking-up, adjust and place safety stands
to
support
•
the
vehicle approximately level, and lower
the
vehicle
onto
stands. When placing safety stands,
take
care
not
to
damage
the
brake fluid and fuel pipes.

I
MPORT
ANT INFORMATION
B
AS
IC ASSUMPTIONS
This service manual assumes
that
you h
av
e and know how
to
properly use
certain special tools which are necessary for the safe and efficient perfor-
mance
of
service operations on Mazda vehicles. The manual also assumes
that you are familiar generally with automobile systems and basic service
and repair procedures. You should
not
attempt
to
use
this manual unless
these assumptions are correct and you understand the consequences des-
cribed below.
SAFETY
RI
SK
This manual contains certain
caut
ions which you should carefully read
and follow in order' to minimize the risk
of
personal
injury
to
you
or
others
and the risk
of
improper service methods which may damage your Mazda
or render it unsafe. The fact that there are no cautions with respect to any
specific service method does
not
mean that there
is
no safety risk involved.
YOU SHOULD SATISFY YOURSELF I EVERY CASE THAT NEITHER
PERSONAL SAFETY OR VEHICLE SAFETY WILL
BE
JEOPARDIZED
BY
THE SERVICE METHOD OR TOOLS YOU SELECT.
POSSIBLE
LOSS
OF WA
RRA
NTY
The m
an
ufacturer's warranty
of
Mazda vehicles and engines can
be
voided
by improper service or repairs performed by persons other than
an
authorized
Mazda dealer.
Strict compliance with the instructions in this manual
is
necessary to prevent
loss
of
coverage under such warranties.
GENER
AL
SERVICE
INS
TRU
CTIONS
1.
If
a vehicle
is
to
be
jacked up only at the front or rear end,
be
sure
to
block wheels
in
order to ensure safety.
2.
After a vehicle
is
jacked up, do not f
ail
to support it with stands (rigid
racks).
3.
Use
fender covers, seat covers and
fl
oor covers
to
keep vehicle clean
• and prevent any damage.
4. Before servicing
an
electrical system, always disconnect the negative
cable at the battery (- ) terminal.
5.
Do
not
start
to
disassemble at once. Always make sure first whether the
trouble is
of
the kind
that
requires disassembly.
6.
If
a complecated place
is
to
be
disassembled, place punch marks, match
marks, etc., at place that will
not
affect function
in
order to make
re
-
assembly work eas
ie
r.
7. Always replace the used gaskets, "O" rings and split pins with new ones.
8. Apply sealer or grease at the parts called for.
9. Tighten the bolts and nuts
to
specified torque using a torque wrench.
10. Some
of
the service operations require the special tool.
Be
sure
to
use
the special tool where specified and follow the correct working procedure.

1981
Mazda626
Workshop Manual
Engine ..
Emission Control System {U.S.A.) Dill
Emission C ontrol System {Canada) ~
Lubricating System lfJI
Cooling System llm
Fuel System{U.S.A.) Em
FOREWORD
This workshop manual was prepared as
reference material of the service personnel of
authorized Mazda dealers to enable them to
correctly carry out the task of rendering ser vi ces
and maintenance
on Mazda vehicles·.
In order to ensure that the customers are
satisfied with Mazda products, proper servicing
and maintenance must be provided. For this
purpose, the service personnel must fully under-
stand the contents
of this manual and at same
time, are recommended
to keep the manual in
a place where reference can readily be made.
The information, photographs, drawings and
specifications entered in this manual were
the best available at the time of printing this
manual.
All alterations to.this manual occurring
as the result of modifications will be notified
by the issuance
of Service Informations or
supplementary volumes.
It is , therefore, re-
quested
that the manual be kept up to date by
carefully maintaining a follow-up of these
materials. •
Toyo Kogyo reserves the right
to alter the
specifications and contents of this manual
without obligation and advance notice.
All rights reserved. No part of this book
may be reproduced or utilized in any form
or
by any means, electronic or mechanical,
including photocopying, recording, or by any
informational storage and retrieval system,
without permission in writing.
Fuel System{Canada) 11.i.111
Electrical System
Clutch
Transmission {Five-speed)
Automatic Transmission
Propeller Shaft
Rear Axle
Steering
Power Steering
Brakes
Wheel and Ti res
Suspension
Body and Frame
Electrical System
{Body)
Technical Data
Special Tools
Toyo Kogyo Co.,Lt d.
HIROSHIMA . .JAPAN © 1980
TOYO KOGYO CO ., LTD.
PRINT
ED IN JAPAN '80
1041-10.SOH

1
ENGINE
1-
A.
ENGINE RE
MOVAL
. . . . . . . . . . . . . . I : I
1-
B.
ENGINE
DISASSEMBLY
. . . . . . . . . . . I : 3
1-C.
ENGINE INSP
ECTI
ON
AND
REPAIR
..
1 : 6
l
-C-1.
Checking Cylinder Head . . . . . 1 : 6
l
-C-2.
Checking Manifold . . . . . . . . . 1 : 6
l- C
-3.
Checking
Valve'
Spring
......
1 : 7
l-C
-4. Checking
Valve
. . . . . . . . . . . 1 : 7
l-
C-5.
Checking
Valve
Stem
to
Guide Clearance . . . . . . . . . . . l : 8
l-C
-
6.
Replacing
Valve
Guide . . . . . . 1 : 8
1-C-
7. Refacing Valve. . . . . . . . . . . . I : 9
l-C-8
. Inspecting and Refac
ing
Valve
Seat
...............
1 : 9
l - C
-9
. Checking Contact between
Valve
and
Valve
Seat.
. . . . . . I : 9
1-C-10.
Checking
Valve
Seat Sinking
..
1 :
10
l
-C-11.
Checking Rocker Arm and
Shaft. . . . . . . . . . . . . . . . . . . 1 : 10
l-C
-12.
Checking Cylinder
Bl
ock
.....
1 :
JO
l-C-13.
Checking Cylinder Bore
.....
1 : 1
J
l-C
-14. Checking Piston
...........
l :
12
1-C
-l
S.
Checking Piston Clearance. . . . 1 :
12
l
-C-16.
Checking Piston Ring
Groove
..
.
..............
I :
12
I
-C-
1
7.
Checking Piston Ring
End Gap
................
1:
12
l-C
-18. Connecting Rod Bearing
.....
1 :
13
l- C- 19. Checking Connecting Rod
Bearing Clearance . . . . . . . . . . l :
13
•
l-C-20.
Checking Connecting Rod
Side Play
................
1 :
13
l - C- 21. Checking Connecting Rod
Alignment . . . . . . . . . . . . . . . I :
13
l-C-22.
Checking
Main
Journal and
Crankpin . . . . . . . . . . . . . . . . l : 14
l - C- 23. Checking Crankshaft
Alignment . . . . . . . . . . . . . . . 1 :
14
1-C-24.
Main
Bearing
.............
1 : 14
l - C- 25. Checking
Main
Bearing
Clearance. . . . . . . . . . . . . . . . l :
15
l
-C-26.
Checking Crankshaft
End Play . . . . . . . . . . . . . . . . l :
15
l-C-27
. Checking Camshaft.
........
1 :
15
l-C-28.
Checking Camshaft Run-Out
..
1 :
16
l
-C
-29. Camshaft Bearing . . . . . . . . . . I :
16
l-C-30.
Checking Camshaft Bearing
Clearance. . . . . . . . . . . . . . . . 1 : 16
l- C-
.31.
Checking Camshaft End Play. . l : I6
l
-C-32.
Checking Timing Chain,
Oil
Pump
Drive
Chain and Sprockets . . . 1 :
17
l
-C-33.
Checking Chain Adjuster. . . . . 1 :
17
l- C
-3
4. Checking Chain Guide Strip
and Vibration Damper . . . . . . 1 :
17
1-D.
ENGINE
ASSEMBLY
. . . . . . . . . . . . . . 1 : 17
1- E. ENGINE INSTALLATION
........
...
1 : 27
1- F. CHECKING COMPRESSION
PRESSURE . . . . . . . . . . . . . . . . . . . . . 1 : 27
SPEC
IAL TOOLS. . . . . . . . . . . . . . . . . . . . . 1 : 27
..

1
Fig. 1- 1
Fig.
1-2
Fig.1-3
Fig.
1-4
l : I
1-A.
ENGINE REMOVAL
Inside
of
engine compartment :
Remove and disconnect the following parts from the
engine.
1. Bonnet
2.
Battery negative cable
3.
Cooling water (drain)
Note:
To
avoid
the
danger
of
being burned up,
do
not
remove
the radiator drain plug while
the
coolant
is
hot.
4.
Upper and lower water hoses
5.
Fluid pipes (automatic transmission only)
6. Radiator cowling and cooling
fan
7.
Radiator
8.
Air hoses from air cleaner
9. Air cleaner
Note:
After removing
the
air cleaner, cover
the
carburetor
with a
clean shop towel
to
prevent dust
or
dirt
from
entering.
10.
Wiring for
1)
Distributor primary
2) Hightensi
on
cord and condenser (IG. coil to
distributor)
3)
Pickup coil
4) Oil pressure switch
5)
Alternator
"B"
tenninal
6)
Alternator wiring coupler
11. Engine mounting
nut
(right side)
12. Wiring for
I)
Water temperature gauge unit
2) Fuel cut solenoid
3)
Air
vent solenoid
4)
Automatic choke
5) Starting motor
6)
Engine earth
13. Air hoses
14. Vacuum hoses (three way solenoid valve)
15. Fuel hoses
16. Acceleration wire
17. Master vac vacuum hose
18. Heater hoses
19. Engine mounting
nut
(left side)

Fig . 1 -5
Fig. 1-6
Fig. 1-7
Fig.1-8
1
Underside of vehicle :
Raise the front end of the vehicle and support with
stands.
Remove and disconnect the following parts from the
engine.
1. Under cover
2. Exhaust pipe
3. Clutch
~nder cover plate and stays
4. Torque converter and driving plate support bolts
(automatic transmission only)
5. Transmission supporting bolts and nuts
Note:
Support the transmission with a suitable jack.
6. Starting motor
7. Clutch release cylinder
Install a suitable lifting sling on the engine hanger.
Attach the sling to the hoist or other lifting device
and take up
all slack.
Pull the engine forword until it clears the clutch shaft.
Then, lift the engine from the vehicle.
Before installing the engine to the engine stand, remove
the following parts from the engine.
1. E.G.R. pipe
2. Air injection pipe
3. Reed valve (Canada)
4.
Air injection nozzle (U.S.A.)
5. Air injection pipe joint (Canada)
6. Exhaust manifold
7. Alternator
8. Engine mounting brackets
9. Emission control parts
1) E.G.R. valve
2) Air pump (U.S.A.)
3) Water thenno valves
4) Water thermo switch (Canada)
5) Anti-afterbum valve (manual transmission only)
(Canada)
Mount the engine on the engine stand (49 0107 680A
and 49 0221 005A).
1 ; 2

1
Fig.
1-9
vvnmn
17nvnC0.67m
)
Chai
n adjuster
Fig. 1-
10
Fie.
1-11
•
Fig.
1-12
I : 3
1-B
.
ENGINE
DISASSEMBLY
Remove the following parts from the engine.
I. Engine oil (drain)
2. Distributor
1) Hightension cord
2)
Vacuum sensing tube
3. Alternator bracket
I)
Alternator strap
2)
"V"
belt
4.
Oil
filter
S.
Inlet manifold and carburetor
6. Water pump
7. Thermostat
Before disassembling, check the protrusion
of
chain
adjuster
as
follows:
1.
Move the stop lever
of
chain adjuster
to
slipper
head side.
2. In the above condition,
tum
the crank shaft counter
clockwise and push in the slipper head and install
the chain adjuster
guide
(49 3953 260).
3.
Tum
the crank shaft clockwise.
4. Readjust the chain guide
as
explained
on
page 1 : 21.
S.
If
the protrusion amount exceeds 17
mm
{0.67 in),
replace the chain.
Cylinder head :
I.
Rocker arm cover and gasket
2.
Oil
seals
3. Blind cover
Note :
After removi
ng
the
blind cover, install
the
chain adjuster
guide (49 3953 260)
to
prevent
the
slipper head
of
the chain adjuster from
popping
out.
4.
Lock
nut
(distributor drive gear)
S.
Lock nut (camshaft sprocket)
Use
the brake
(49
0118 271A) and spanner (49
0164 631A)
6. Bolt (cylinder head
to
cylinder block)
7. Cylinder head bolts
Note :
To
avoid
the
cylinder head distortion, loosen the
bolts
a few turns
at
a time until
they
are all loose.
8. Rocker arm assembly
9.
Camshaft and bearings
10. Camshaft sprocket
-

Fig. 1-13
Fig. 1-14
Fig. 1-15
Fig. 1- 16
1
11. Cylinder head and gasket
Note:
When removing only the camshaft or the cylinder
head, the timing chain should be lifted upward
to
prevent the slipper head of the chain adjuster from
flying
out and causing a difficulty in adjusting the
timing chain.
Valve and valve spring :
Remove the valve and valve spring, use the valve spring
lifter (49 0636
IOOA) and pivot (49 0221 222A) and
compress the valve spring.
1. Taper sleeves
2. Valve spring upper seats
3. Valve springs (outer and inner)
4. Valve spring lower seats
5. Valve (inlet and exhaust)
Note:
Place the taper sleeves, upper spring seats, valve springs,
lower spring seats and valves in order
in a suitable case
for reassembling.
Crankshaft pulley and clutch assembly :
Remove the crankshaft pulley and clutch assembly,
use the brake
(49 0118 271A).
1. Pulley bolt
2. Crankshaft pulley
3. Clutch cover and pressure plate assembly
4. Clutch disc
5. Flywheel (manual transmission)
Driving plate (automatic transmission)
1 : 4

1
Fig. 1- 17
Fig.
1-18
Fig.
1-19
P
iston
Connecting
rod
ipi:lllltl~1
fig.
1- 20
I :
5
Oil
pan and timing chain :
Rotate the cylinder block upside down position.
I.
Oil
pan and attaching bolts
2. Timing chain cover and gasket
3. Oil thrower
4. Oil pump sprock
et
lock
nut
and washer
5. Oil pump drive chain and sprocket
6. Timing chain and sprocket
7.
Crankshaft key
8. Vibration damper
9.
Chain guide strip
10. Chain adjuster (with chain adjuster guide)
11. Oil strainer
12. Oil pump assembly
Pi
st
on
and connecting rod :
l.
Connecting rod caps and bearings
2.
Piston and connecting rod assemblies
3. Piston pin
Use
the pre
ss
and piston pin setting tool (49 8134
040)
Arrange the installer (
49
8134 04
2)
and removing
guide (49 8134 045) on the piston and connecting rod,
and set the assembly on the support block (49
81
34
041)
as
shown in Fig. 1- 20.
P
ress
out the piston pin.

fi9.
1- 21
Fig.
1-22
height
Fig.
1-23
Fig.
1-24
1
4.
Main bearing caps and side seals
Use
the puller
(49
0221
2708)
S.
Main
bearings and thrust bearings
6. Rear oil seal
7. Crankshaft
1-C
. ENGINE INSPECTION
AND
REPAIR
1-C-1.
Checking Cylinder Head
Check to see the water passages are open. Inspe
ct
the tapped openings. Repair or replace any damaged
threads or broken studs.
Check for cylinder head distortion by placing a
st
raight
edge on the cylinder head surface. Measure the clearance
between the straight edge and the cylinder head surface
with a feeler gauge.
If
the distortion exceeds 0.
15
mm (0.006 in), grind with
a surface grinder
or
replace the head.
Cylinder head hight
Grinding Limit
1-C-2.
Checking Manifold
109
±
0.
05
mm
(4.291 ± 0.002 in)
0
.2
0mm
(0.008 in)
Check the inlet and exhaust manifold for distortion.
To check, place the straight edge
on
the manifold.
Measure the clearance between the manifold and surface
plate
with
a feeler gauge.
If
excessive distortion
is
found, correct
it
by
grinding.
Limit 0.15 mm (0.006 in)
I : 6

1
Fig.
1-25
Fig. 1
-2
6
Fig.
1-27
l : 7
1- C- 3. Checking Valve Spring
Examine the springs for corrosion or any damage.
If
it
is
severe, replace with new ones.
Mea
sure the
free
length and the fitting pressure.
The specifications
of
the springs are
as
follows :
Inner sprin2
Outer
spring
Standard Limit Standard Limit
Free length 36.8
mm
35.7
mm
37.3
mm
36.2
mm
(l.449
in) (1.406 in)
(1
.469 in) (1.425 in)
Fitting load 9.5 kg 8.1 kg 14.25 kg 12.1
kg
(20.9 lb) (17.9 lb) (31.4 lb) (26.7 l
b)
Filling length
32.0
mm
(1
.2
60
in) 34.0 mm
(l.339
in)
1
-C-4.
Checking Valve·
Remove all carbon from the valves. Visually inspect
all
valves
for warpage, cracks
or
excessive burning
and replace
if
any
of
these conditions are found.
Replace any worn, pitted or corroded
valves
that can
not be cleaned or refaced.
Measure the diameter
of
the
valve
stem at two
or
three
places along the length
of
the stem with a micrometer.
Replace
if
the stem diameter
is
less than 7.980
mm
(0.3
142
in) on the inl
et
valve
and 7.975 mm
(0
.3140
in)
on
the
exhau
st
valve.
The standard diameter
is
8.0
mm
(0.3150 in).

Fig, 1- 28
L
--1;--[-_---- ----r-r- ___ ;g -----r+-_ _ IN
Fig. 1-30
Fig. 1- 31
1-C -5 . Checking Valve Stem to Guide Clearance
The standard clearance between the
va l ve stem and
guide should be, under the condition
of the guide being
fitted with the cylinder head, 0.018 -0.053 mm
(0. 0007 -0.0021 in) on the inlet side and 0.018 -
0.0
58 mm (0. 0007 ~ 0.0023 in) on the exhaust side.
To check this clearance, place the va lv e in each guide:
Check the clearance with a suitable mounted dial indi-
cator, or
feel the clearance by moving the stem back a nd
forth. If the clearance is 0. 20 mm (0.008 in) or more;
replace the valve guide and valve.
1
-C-6. Replacing Valve Guide
I. Press
out the old guide with the puller & installer
(49 0221 251A).
2. Press in the new guide squarely with the same tool
until the ring on the guide touches the cy
li nder
head.
Note:
Inlet and exhaust v al ve guides are different as shown
in F ig. 1-30 .
3. Install the new
va l ve seal onto the va l ve guide with
the pusher (49 0223 160D).
Not e:
When installing the va lve seal, be careful not to twist
and check
to see if the valve moves smoothy.
I : 8

1
s:~
:
~~~mm
n
(0.
315
+o.001S In)
+0.0010
8
+0.045
mm
c
·-
+O
030 E ·-
E
,...
· E
,...
E
~
(0.315 +
O.OOlS
in)
~
;:::
,._ N
+Q0012
IX>
N
o~
·
o~
--
--
EXHAUST
INLET
Fig. 1-
32
Fig.
1-33
INL
ET
EXHAUST
Fig.
1-34
I : 9
-
37
mm
11.4567")
28mm
(1.1024"')
1.4
mm
(0.055"
1-
C-7
. Refacing Valve
Reface the valves with a
valv
e
re
facer, following the
instructions
of
the valve refacer manufacturer.
The inlet and exhaust valve face has a
45
degree angle.
Take
off
only the minimum
of
metal required
to
clean
the
vaJve
faces.
Note:
If
the
outer
edge
of
the
valve (valve margin) becomes
less than 1.0 mm (0.039
in)
from exccessive grinding,
the
va
lv
e must be replaced.
1-C-8.
Inspecting and Refacing Valve
Seat
Inspect the valve seats for cracks, burrs, ridges
or
im-
proper angle and width.
If
necessary to reface the
valve
seats, use a valve seat grinder
or
valve seat cu
tter
and grind to a
45
degree angle. Do
not
grind any more
than
is
necessary to clean up the valve seat.
Note:
a)
If
the
valve guides are
to
be replaced, this must
be done before refacing
the
valve seat.
b)
The valve seat ring
is
shrinkage-fitted in
the
cylinder
head. However,
the
seat ring
cannot
be
replaced
in view
of
maintaining strength.
1- C- 9. Checking Contact between Valve and Valve
Seat
After the
valve
or
valve seat is ground, check
the
contact
between
the
valve and valve seat
as
follows:
I. Apply a thin coat
of
Prussian Blue on the valve
face and insert
the
valve into the valve seat.
2. Move
the
valve
up
and down with hand pressure,
rotating the valve.
3.
Remove the valve and observe the transfer
of
Prus-
sian Blue to the valve seat.
An
even transfer indicates accurate valve and valve
seat refacing.
If
uneven, the valve must be lapped into
the valve seat, using a suitable lapping compound.
4.
Check the
valve
seat width with a scale.
The valve seat width
is
1.4 mm (0.055 in) on
the
both inlet and exhaust valve seats.
If
the
valve seat width
is
too
wide,
it
can be reduced
from inside
with
a
75°
seat
cutter
and from outside
with a
15°
seat cutter.

Fig . 1-35
Fig.1-37
IN. 40.9mm
(1.61in)
EX. 37.9mm
( 1.49 i n)
1
1-C-10. Checking Valve Seat Sinking
Check the sinking of the valve seat by using a vernier
calipers
as shown in Fi g. 1 -3 5.
If the sinking exceeds 0.5 mm (0.020 in), washers of
sufficie nt thickness to compensate the sinking mu st be
placed under the springs so as to maintain the specified
spring pressure.
If it is more than 1.5 mm (0.059 in),
replace the valve.
1-C-11. Checking Rocker Arm and Shaft
The standard clearance between the rocker arm bore
and shaft
is 0. 027 -0.081 mm (0.0011 -0.0032 in).
Inspect the clearance and if it is more than 0.10 mm
(0.004 in), replace the rocker arm or shaft.
1- C- 12. Checking Cylinder Block
Clean t he cylinder block with a suitable solvent. Spe-
cial care must be taken when cleaning the oil pas-
sages, coolant passages and cylinder bore
to remove
all sludge, dirt and carbon deposit. After cleaning,
use compressed air to dry the block thoroughly.
Examine the cylinder block for crack and any damage.
Examine
all machined surfaces of the block for burrs
and scores.
Check the cylinder block for distortion in the same
way, as described in Par. l -C-1.
Distortion limit 0.
15 mm (0.006 in)
1 : 10

11
Fig.
1-
38
y
y
fig.
1-
39
J :
11
1-C-13.
Checking Cylinder Bore
Check the cylinder bores for wear, scratching and
waviness.
Measure the diameter
of
the
cylinder bore
by
using
a cylinder gauge.
This measurement should
be
taken
in
the
X-X direc-
tion and the Y-Y direction
at
each
of
the
3 sections,
upper
, middle and lower,
of
one
cylinder, as shown
in Fig. I
39
.
The difference
between
the
minimum and maximum
values
out
of
the
6 measured values is regarded as
the
amount
of
wear.
If
the
wear
of
cylinder
bore
is 0.15 mm
(0.0059
in)
or
more, it should be honed
or
rebored.
Honing and reboring should
be
made
to
correspond
to
piston
and rings oversize and
to
the
recommended
piston
clearance
of
0.
036
-
0.075
mm
(0.0014
-
0.0030
in).
The following oversize piston and rings are available:
0.25
mm
(0.010 in) 0.50
mm
(0.020
in)
Note :
If
any
one
of
the
cylinder bores requires reboring,
the
remaining ones also
re
qu
ire reboring.

Fig. 1
-40
Fig.
1-41
Fig. 1
-42
•
Fig.
1-43
1
1- C-
14.
Checking Piston
Carefully inspect the piston and replace
if
it is severely
scored, scratched
or
burned.
Measure the diamet
er
of the piston without the piston
pin fitted
by
means
of
a micrometer.
The
standard diameter are as sho
wn
in
Fig.
1-41.
If
the wear is severe, replace
the
piston.
1-C-15.
Checking Piston Clearance
Check the clearance between each piston and cylinder
by
measuring
the
diameter
of
the pi
sto
n and cylinder.
Measure the pist
on
diameter
at
right angle
to
the
pis-
ton
pin and
18.5
mm
(0.73 in) below
the
ring groove.
The
standard clearance is 0.
036
- 0.
075
mm
(0.0014 -
0.0030
in).
If
the
clearance exceeds
0.15
mm (0.006 in). rebore
the
cylinders and use the oversize pistons and rings,
referring
to
Par. 1- C- 13.
A:
79.954
± 0.01
mm
(3.1478
±
0.0004
in)
B:
79.980
mm
(3.
1489
in)
C:
79.550
mm
(3.1319
in)
1-
C-16.
Checking Piston Ring Groove
Remove the
carbon
from the pi
sto
n ring grooves
by
using a ring groove cleaner
or
a broken piece
of
piston
ring.
Wi
th
a feeler gauge, check the side clearance
of
the
piston rings
at
several places.
If
1t
is improper, replace the pi
sto
n rings.
Standard:
Top
ring
Second ring
Limit
0.030
-
0.070
mm
(0.
0012
-
0.0028
in)
0.030
-
0.064
mm
(0.0012-0.0025 in)
0.15
mm
(0.006
in)
1- C- 17. Checking Piston Ring End Gap
Place t
he
piston ring in the cyli
nder
bore
below
the
ring travel, using a piston head
to
push
the ring in
squarely.
Check the piston ring
end
gap
with
a feeler gaug
e.
Standard:
Top
& second ring
0.2
-
0.4
mm
(0.008 -
0.016
in)
Oil ring 0
.3
-
0.9
mm
(0.012 -
0.035
in)
Limit
1.0
mm
(0.039
in)
I :
12
.,

1
Fig. 1-44
Fig, 1-47
l : 13
1-C-18 . Connecting Rod Bearing
The connecting rod bearing sets are available
in the
standard size and undersize
of 0.25, 0.50 and 0.75
mm (0.010, 0.020 and 0.030 in).
Inspect the bear
in g carefully and replace if it is worn,
scored or flaked.
Each bearing consists
of two halves and should be
replaced
as a set.
1-C-19 . Checking Connecting Rod Bearing Clearance
1. Clean the surfaces of the bearing and crankpin.
2. Place the "Plasti ga ug e" on the crankpin.
3. Install the bearing cap and tighten the bolts to
4.1 -4.6 m-kg (30 - 33 ft-lb).
4. Remove the bearing cap and measure the width
of the "Plastigauge", using the scale printed on the
envelope. The connecting rod bearing clearance
is
0.027 -0.077 mm (0.0011 - 0.0030 in). Correct if
the clearance exceeds 0 .1 0 mm (0.0039 in).
1-C-20 . Checking Connecting Rod Side Play
Check the connecting rod side play with a feeler gauge.
The side play should be between 0.11 -0.21 mm (0.004
-0.008 in).
1-C-21. Checking Connecting Rod Alignme nt
Check the connecting rod for bend or twist by using
a suitable alignment fixture. Follow the instructions
of the fixture manufacturer. If the bend or twist exceeds
specificatio
ns , the connecting rod must be straightened
or replaced.
Permissible deflection :
0.02 mm (0.0008 in) Per
50 mm (2 in)
..

Fig. 1-48
\._,
Fig. 1-49
Fig. 1-50
1
1-C-22 . Checking Main Journal and Crankpin
Clean the crankshaft thoroughly with a suitable so
l-
vent and blow out the oil passages with compressed
air.
In spect the crankshaft for crack, scratch and t he o il
passages for clog.
Measure the diameter
of each crankpin and main journal
with a micrometer.
If the wear is more than 0.05 mm
(0.0020 in), the crankshaft should be ground to the
undersize
of 0.25, 0.50 and 0.75 mm (0.010, 0.020 and
0.030 in) or replaced.
The standard diameter of the crankpins and main
journals are shown in the following table.
Crankpin
53 - 0.045 (2 0866 -0.0018 .
-0.060
mm · - 0.0024 m)
Main journal 63 -0.045 (2 4804 -0.0018 .
-0.060
mm • - 0.0024 m)
1-C- 23 . Checking Crankshaft Alignment
To check alignment, mount the crankshaft on the
"V" blocks and apply a dial indicator. Slowly rotate
the crankshaft and note the reading on the dial indi-
cator. The maximum allowable run-out
is 0. 03 mm
(0.00 12 in).
If it is not within specification, replace the crankshaft
with new one.
1-C-24. Main Bearing
The main bearings are classified into 2 types according
to the shape as shown in Fig. 1-50 .
The main bearings are available in the standard size
and undersize of 0.2 5, 0.50 and 0.75 mm (0.010,
0.020 and 0.030 in).
Inspect the bearings carefully for wear, scoring, flaking
or any damage. If any of these conditions exists, replace
with new bearings.
Each bearing consists of Lwo halves and should be
replaced as a set.
1 : 14