1987 MAZDA 626 Workshop Manual

INSPECTION AND REPAIR 1 B
76G01A-128
L 75° 75/ 60° 60
35°>
450 V EX '%50 IN
86U01X-088
76G01B-055
5. Check the seat contact width.
Width: 1.2—1.6 mm (0.047—0.063 in)
6. Check that the valve seating position is at the cen-
ter of the valve face.
(1) If the seating position is too high, correct the
valve seat with a 60° cutter and a 45° cutter.
(2) If the seating position is too low, correct the
valve seat with a 35° (IN) or 15° (EX) cutter
and a 45° cutter.
7. Seat the valve to the valve seat with a lapping
compound.
8. Check the sinking of the valve seat.
Measure protruding length (dimension L) of each
valve stem.
Dimension L: 36.8 mm (1.449 in)
(1) If L is as below, it can be used as it is.
36.8—37.6 mm (1.449—1.480 in)
(2) If L is as below, insert a spacer between the
spring seat and cylinder head to adjust.
37.6—38.3 mm (1.480—1.508 in)
(3) If L is more than as below, replace the cylin-
der head.
38.3 mm (1.508 in) or more
Valve Spring 1. Inspect each valve spring for cracks or damage.
2. Check the free length and angle. Replace if
necessary.
Free length
Outer Standard: 39.1 mm (1.539 in)
Minimum: 38.7 mm (1.524 in)
Inner Standard: 38.0 mm (1.496 in)
Minimum: 37.7 mm (1.484 in)

76G01B-059

1B-38

INSPECTION AND REPAIR 1 B
-Angle limit
76G01B-057
86U01X-092
76G01B-058
Angle
Outer: 1.4 mm (0.055 in) max.
Inner: 1.3 mm (0.051 in) max.
Camshaft
1. Set the front and rear journals on V-blocks.
Check the camshaft runout. Replace if necessary.
Runout: 0.03 mm (0.0012 in) max.
2. Check the cam for wear or damage. Replace if
necessary.
3. Check the cam lobe height at the two points as
shown in the figure.
Height:
45.055 mm (1.7738 in) Leaded fuel
45.052 mm (1.7737 in) Unleaded fuel
Minimum:
44.855 mm (1.7659 in) Leaded fuel
44.852 mm (1.7658 in) Unleaded fuel
4. Measure wear of the journals in X and Y directions
at the two points as shown in the figure.
Diameter:
29.940—29.965 mm (1.1787—1.1797 in)
Out-of-round: 0.05 mm (0.002 in) max.
76G01B-059
1B-39

1 B INSPECTION AND REPAIR
5. Measure the oil clearance of the camshaft and
camshaft caps.
(1) Remove any oil or dirt from the journals and
bearing surface.
(2) Set the camshaft onto the cylinder head.
(3) Position plasti-gauge on top of the journals in
the axial direction.
76G01B-060
(4) Place the camshaft caps according the cap
number and arrow, and tighten them in the or-
der shown in the figure.
Tightening torque:
18—26 N-m (1.8—2.7 m-kg, 13—20 ft-lb)
76G01B-061
(5) Loosen the camshaft cap bolts in the order
shown in the figure.
76G01B-062
(6) Measure the oil clearance at each cap.
Oil clearance:
0.035—0.085 mm (0.0014—0.0033 in)
Maximum: 0.15 mm (0.0059 in)
(7) If the oil clearance exceeds the maximum, re-
place the camshaft and/ or the cylinder head.
76G01B-063
1B—40

INSPECTION AND REPAIR 1 B
76G01B-125
76G01B-064
86U01X-100
6. Measure the camshaft end play. If it exceeds the
maximum, replace the camshaft and/or the cylin-
der head.
End play:
0.08—0.10 mm (0.003—0.004 in)
Maximum: 0.20 mm (0.008 in)
Hydraulic Lash Adjuster (HLA)
1. Check the HLA face for wear or damage.
2. Hold the HLA between your fingers and press it.
If the HLA moves, replace it.
Caution
Do not disassemble the HLA.
Cylinder Block
1. Check the cylinder block. Repair or replace if
necessary.
(1) Leakage damage
(2) Cracks
(3) Scoring of wall
2. Measure the distortion of the top surface of the cyl-
inder block in the six directions as shown in the
figure.
Distortion: 0.15 mm (0.006 in) max.
3. If the distortion exceeds the maximum, repair by
grinding, or replace the cylinder block.
Grinding limit: 0.20 mm (0.008 in) max.
86U01X-101
1B—41

INSPECTION AND REPAIR 1 B
o ^ ^o
(7/T\V
-A-
B-
-c-
79G01C-070
1- B
79G01C-071
79G01C-072
4. Measure the cylinder bore in directions X and Y
at three levels in each cylinder as shown.
Cylinder bore mm (in)
Size Bore
Standard 86.000-86.019 (3.3858-3.3866)
0.25 (0.010) oversize 86.250-86.269 (3.3957—3.3964)
0.50 (0.020) oversize 86.500—86.519 (3.4055-3.4062)
(1) If the difference between the measurement A
and C exceeds the maximum taper, rebore the
cylinder to oversize.
Taper: 0.019 mm (0.0007 in) max.
(2) If the difference between the measurement X
and Y exceeds the maximum out-of-round, re-
bore the cylinder to oversize.
Out-of-round: 0.019 mm (0.0007 in) max.
Caution
The boring size should be based on the size
of an oversize piston and be the same for all
cylinders.
5. If the upper part of the cylinder wall shows uneven
wear, remove the ridge with a ridge reamer.

86U01X-101

1B—42

INSPECTION AND REPAIR 1 B
Oil ring
groove
18mm IJUv. (0.709 in)*"! ^
79G01C-073
r Clearance
76G01A-130
69G01A-125
HV JT
101
^^Piston ring
vAv n^-n
iXXi ^^Piston ring ^^Piston ring
Piston
1. Inspect the outer circumferences of all pistons for
seizure or scoring. Replace if necessary.
2. Measure the outer diameter of each piston at a right
angle (90°) to the piston pin, 18 mm (0.709 in)
below the oil ring land lower edge.
Piston diameter mm (in)
Size Diameter
Standard 85.944—85.964 (3.3836—3.3844)
0.25 (0.010) oversize 86.194-86.214 (3.3935-3.3942)
0.50 (0.020) oversize 86.444-86.464 (3.4033-3.4041)
3. Check the piston to cylinder clearance.
Clearance:
0.036—0.075 mm (0.0014—0.0030 in)
Maximum: 0.15 mm (0.0059 in)
4. If the clearance exceeds the maximum, replace the
piston or rebore the cylinders to fit oversize pistons.
Caution
If the piston is replaced, replace the piston
rings also.
Piston and Piston Ring
1. Measure the piston ring to ring land clearance
around the entire circumference using a new pis-
ton ring.
Clearance (Top and Second):
0.03—0.07 mm (0.001—0.003 in)
Maximum: 0.15 mm (0.006 in)
2. If the clearance exceeds the maximum, replace the
piston.
Inspect the piston rings for damage, abnormal
wear, or breakage. Replace if necessary.
Insert the piston ring into the cylinder by hand and
push it to the bottom of the ring travel in using the
piston.

86U01X-101

1B—43

1 B INSPECTION AND REPAIR
76G01B-065
%
-X
@H
C/ v M v M
76G01B-066
76G01B-067
5. Measure each piston ring end gap with a feeler
gauge. Replace if necessary.
End gap
Top : 0.20—0.35 mm (0.008—0.014 in)
Second: 0.15—0.30 mm (0.006—0.012 in)
Oil rail : 0.20—0.70 mm (0.008—0.028 in)
Maximum: 1.0 mm (0.039 in)
Piston and Piston Pin
1. Measure the piston pin hole diameter in X and Y
directions at four points.
Diameter:
21.988—21.998 mm (0.8657—0.8661 in)
2. Measure the piston pin diameter.
Diameter:
21.987—21.993 mm (0.8656—0.8659 in)
3. Determine the piston pin to piston clearance by
subtracting the two figures.
Clearance:
-0.005—0.011 mm (-0.0002—0.0004 in)
4. If the clearance exceeds the specification, replace
the piston and/or piston pin.
Connecting Rod
1. Measure the connecting rod small end bore.
Diameter: 22.003—22.014 mm (0.8663—0.8667 in)
2. Check the clearance between the small end bore
and piston pin.
Clearance:
0.010—0.027 mm (0.0004—0.0011 in)

76G01B-063

1B—44

INSPECTION AND REPAIR 1 B
3. Check each connecting rod for bending or twist-
ing. Repair or replace if necessary.
Bend: 0.06 mm (0.0024 in) max.
Twist: 0.06 mm (0.0024 in) max.
86U01X-108
Crankshaft
1. Check the journals and pins for damage, scoring,
or oil hole clogging.
2. Set the crankshaft on V-blocks.
3. Check the crankshaft runout at the center journal.
Replace if necessary.
Runout: 0.03 mm (0.0012 in) max.
86U01X-109
4. Measure each journal diameter in X and Y direc-
tions at two points.
Main journal
Diameter:
59.937—59.955 mm (2.3597—2.3604 in)
Out-of-round: 0.05 mm (0.0020 in) max.
Crankpin journal
Diameter:
50.940—50.955 mm (2.0055—2.0061 in)
Out-of-round: 0.05 mm (0.0020 in) max.
76G01A-131
Crankpin
Main journal
5. If the diameter is less than the minimum, grind the
journals to match undersize bearings.
Undersize bearing: 0.25 mm (0.010 in),
0.50 mm (0.020 in), 0.75 mm (0.030 in)
Main journal diameter undersize mm (in)

69G01A-101

Bearing size Journal diameter
0.25
(0 010)
undersize
0.50 (0.020) undersize

No
1,2,4,5 59.693-59.711 (2.3501-2.3508) 0.25
(0 010)
undersize
0.50 (0.020) undersize
No 3 59.687-59.705 (2.3499-2.3506)
0.25
(0 010)
undersize
0.50 (0.020) undersize
No.1,2,4,5 59.443-59.461 (2.3403—2.3410)
0.25
(0 010)
undersize
0.50 (0.020) undersize No.3 59.437-59.455 (2.3400—2.3407)
0.75
(0 030)
undersize
NO.1,2,4,5 59.193-59.211 (2.3304-2.3311) 0.75
(0 030)
undersize No.3 59.187-59.205 (2.3302-2.3309)
1B—45