MAZDA 626 1987 Workshop Manual

1 B ON-VEHICLE INSPECTION
76G01B-017
86U01X-020
76G01B-018
Possible Cause
ON-VEHICLE INSPECTION
If the engine exhibits low power, poor fuel economy,
or poor idle, check the following points.
1. Ignition system (Refer to Section 5)
2. Compression
3. Fuel system (Refer to Section 4C)
COMPRESSION
1. Check that the battery is fully charged. Recharge
if necessary.
2. Warm up the engine to the normal operating tem-
perature.
3. Turn it off for about 10 minutes to allow the exhaust
manifold to cool.
4. Remove all spark plugs.
5. Disconnect the primary wire connector from the
ignition coil.
6. Connect a compression gauge to No.1 spark plug
hole.
7. Fully depress the accelerator pedal and crank the
engine.
8. Note the maximum gauge reading.
9. Check each cylinder.
Standard compression:
1,422 kPa (14.5 kg/cm2, 206 psi)—290 rpm
Leaded fuel
1,373 kPa (14.0 kg/cm2,199 psi)—310 rpm
... Unleaded fuel
Compression limit:
996 kPa (10.2 kg/cm2, 144 psi)—290 rpm
Leaded fuel
961 kPa (9.8 kg/cm2, 139 psi)—310 rpm
... Unleaded fuel
If compression is low, pour heavy oil into the cylinder and turn the crankshaft several times Check compression once more
»
Is compression increased? Yes 1. Worn piston or piston rings
2. Worn cylinder wall
No
1. Worn piston or piston rings
2. Worn cylinder wall
No 1. Defective cylinder head gasket 2. Distorted cylinder head
Is compression in adjacent cylinder low? Yes
1. Defective cylinder head gasket 2. Distorted cylinder head
Is compression in adjacent cylinder low?
No 1. Improper valve seating
2. Valve sticking in guide
3. Defective cylinder head gasket
86U01X-022
1B—10

ON-VEHICLE MAINTENANCE (TIMING BELT) 1 B
ON-VEHICLE MAINTENANCE
TIMING BELT
Removal
1. Disconnect the negative battery cable.
2. Remove in the sequence shown in the figure referring to the removal note for specially marked parts.
76G01A-108
76G01B-020
1. Center cover
2. High-tension lead and spark plug
3. Engine side cover
4. Drive belt
5. Crankshaft pulley
6. Engine mount bracket
7. Upper timing belt cover
8. Lower timing belt cover
9. Baffle plate
10. Timing belt tensioner
11. Timing belt tensioner spring
12. Timing belt
1B—11

ON-VEHICLE MAINTENANCE (TIMING BELT) 1 B
76G01B-021
Removal note
Timing belt tensioner
1. Turn the crankshaft to align the mating marks of
the camshaft pulleys.
Note
For intake side camshaft pulley, align "I"
mark.
For exhaust side camshaft pulley, align "E"
mark.
2. Remove the tensioner.
Timing belt
Mark the timing belt rotation for proper reinstallation
if it is reused.
Caution
Be careful not to allow oil, grease, or water
on the belt.
86U01X-024
Inspection
Inspect the following parts. (Refer to page 1B—46,
47.)
1. Timing belt
2. Timing belt tensioner and spring
3. Timing belt idler pulley
4. Timing belt pulley
5. Camshaft pulley
76G01B-022
1B—12

1 B ON-VEHICLE MAINTENANCE (TIMING BELT)
Installation
Install in the reverse order of removal referring to the installation note.
Torque Specifications 76G01A-109
8—12 N m (80—120 cm-kg, 69—104 In-lb)
Installation note
Timing belt
1. Check that the mark on the timing belt pulley is
aligned with the mating mark.
2. Check that the mating mark of the camshaft pul-
leys are aligned with the seal plate mating marks.
Note
For intake side camshaft pulley, align "I"
mark.
For exhaust side camshaft pulley, align "E"
mark.

76G01B-026

1B—13

1 B ON-VEHICLE MAINTENANCE (TIMING BELT)
3. Install the timing belt tensioner and spring. Tem-
porarily secure it with the spring fully extended.
Caution
Do not damage the pulleys when securing the
tensioner pulley.
76G01B-024
4. Install the timing belt so that there is no looseness
at the tension side, and at the two camshaft pulleys.
Caution
a) If the timing belt is being reused, it must be
reinstalled to rotate in the original direction.
b) Check that there is no oil, grease, or dirt on
the timing belt.
76G01B-025
5. Loosen the tensioner lock bolt.
6. Turn the crankshaft twice in the direction of rota-
tion, and align the mating marks.
7. Check that the timing marks are correctly aligned.
If not aligned, remove the timing belt tensioner and
timing belt, and repeat steps 1—6.
69G01B-027
8. Turn the crankshaft to align the "S" mark of the
right side camshaft pulley with seal plate mating
mark.
Tighten the timing belt tensioner lock bolt.
Tightening torque:
37—52 Nm (3.8—5.3 m-kg, 27—38 ft-lb)
76G01B-026
1B—14

ON-VEHICLE MAINTENANCE (TIMING BELT) 1 B
10. Check the timing belt deflection. If the deflection
is not correct, repeat the adjustment from step 5
above.
Timing belt deflection: 7.5—8.5 mm
(0.30—0.33 in) /98 N (10 kg, 22 lb)
Caution
Be sure not to apply tension other than that
of the tensioner spring.
76G01B-027
Drive belt
Install each drive belt, and check the belt deflection.
(Refer to page 1B—6.)
76G01B-028
Spark plug
1. Apply anti-seize compound or molybdenum-based
lubricant to the spark plug threads.
2. Install the spark plugs.
Tightening torque:
15—23
N
m (1.5—2.3 m-kg, 11—17 ft-lb)
79G01C-021
Steps After Installation
Perform the necessary engine adjustment. (Refer to
TUNE-UP PROCEDURE.)
86U01X-029
1B—15

1 B ON-VEHICLE MAINTENANCE (CYLINDER HEAD)
CYLINDER HEAD
Removal
Warning: Release the fuel pressure. (Refer to Section 4C.)
1. Disconnect the negative battery cable.
2. Drain the engine coolant.
3. Remove in the sequence shown in the figure referring to the removal note for specially marked parts.
1B—16

76G01B-034

1 B ON-VEHICLE MAINTENANCE (CYLINDER HEAD)
1. Center cover
2. High-tension lead and spark plug
3. Accelerator cable
4. Air intake pipe assembly
5. Fuel hose
6. Upper radiator hose
7. Heater hose
8. Brake vacuum hose
9. Canister hose (Unleaded fuel)
10. Engine harness connector and ground
11. EGR pipe (Unleaded fuel)
12. A/C compressor and bracket
13. Exhaust manifold insulator
14. Exhaust pipe
15. Exhaust manifold
16. Intake manifold bracket
17. Intake manifold assembly
18. Distributor
19. Engine mount stay
20. Upper timing belt cover
21. Timing belt tensioner spring
22. Timing belt
23. Cylinder head cover
24. Cylinder head and gasket
76G01B-030
Removal note
Fuel hose
Warning
a) Cover the hose with a rag because fuel will
spray out when disconnecting.
b) Keep sparks and open flame away from the
fuel area.
Plug the disconnected hoses to avoid fuel leakage.
86U01X-032
Timing belt
1. Before removing the timing belt, turn the crankshaft
to align the mating marks of the camshaft pulleys
with the seal plate timing mark.
Note
For intake side camshaft pulley, align "I"
mark.
For exhaust side camshaft pulley, align "E"
mark.
76G01B-031
2. Loosen the timing belt tensioner lock bolt.
3. Shift the tensioner outward as far as possible, then
temporarily tighten it.

76G01B-034

1B—17

1 B ON-VEHICLE MAINTENANCE (CYLINDER HEAD)
69G01B-037
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76G01A-111
4. Remove the timing belt and secure it out of the way
to prevent damage during removal and installation
of the cylinder head.
Cylinder head bolt
Loosen the cylinder head bolts in two or three steps
in the order shown in the figure.
Disassembly of Cylinder Head
Refer to page 1B—28.
Inspection of Cylinder Head
Refer to page 1B—34.
Assembly of Cylinder Head
Refer to page 1B—59.
76G01B-032
1B—18

1 B ON-VEHICLE MAINTENANCE (CYLINDER HEAD)
Installation
Install in the reverse order of removal referring to the installation note.
Note a) Position the hose clamp in the original location on the hose.
b) Squeeze the clamp lightly with large pliers to ensure a good fit.
Torque Specifications
8—12 N-m (80—120 cm-kg, 69—104
4—6 N-m (40—60 cm-kg, 35—52 in
15—23 N-m (1.5—2.3 m-kg, 11—17 ft-lb)
7—10 N-m (70—100 cm-kg, 61—87 In-lb)
—11 N-m (80—110 cm-kg, 69—95 In-lb)
37—52 N-m (3.8—5.3 m-kg. 27—38 ft-lb)
80—86 N-m (8.2—8.8 m-kj, 59—64 ft-lb)
~t/—- -19—30 N-m (1.9—3.1 m-kg, g^ 14-22 ft-lb)

\34—44
N-m (3.5—4.5 m-kg, ' 25—33 ft-lb)
19-30 N-m (1.9—3.1 m-kg, 14—22 ft-lb)
19—30 N-m (1.9—3.1 m-kg, 14—22 ft-lb)
37—52 N-m (3.8—5.3 m-kg, 27—38 ft-lb)
76G01A-112
1B—19