1987 MAZDA 626 engine

1 C DISASSEMBLY (CYLINDER HEAD)
CYLINDER HEAD
76G01C-079
1. Thermostat cover
2. Thermostat
3. Thermostat case
4. Front and rear engine
hanger
5. Fuel leak pipe
6. Injection nozzle
7. Glow cord
8. Glow plug
9. Camshaft cap
10. Oil seal
11. Camshaft
12. Cylinder head bolt
13. Cylinder head and gasket
14. Tappet and adjusting disc
15. Valve keepers
16. Upper spring seat
17. Valve spring
18. Valve
19. Lower spring seat
20. Valve seal
21. Valve guide and clip
1C-40

INSPECTION AND REPAIR 1C
Piston and Piston Pin
1. Measure the piston pin hole diameter in X and Y
directions at four points.
Diameter mm (in)
RF-CX 29.997-30.007 (1.1810-1.1814)
RF-N 24.997-25.007 (0.9841-0.9845)
76G01C-137
76G01C-139
2. Measure the piston pin diameter.
Diameter mm (in)
RF-CX 29.994-30.000 (1.1809-1.1811)
RF-N 24.994-25.000 (0.9840-0.9843)
3. Determine the piston pin to piston clearance by
subtracting the two figures.
Clearance-
-0.003—0.013 mm (0.0001—0.0005 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 mm (in)
RF-CX 30.014-30.030 (1.1817-1.1823)
RF-N 25.014-25.030 (0.9848-0.9854)
2. Check the clearance between the small end bore
and piston pin.
Clearance*
0.014—0.036 mm (0.0005—0.0015 in)
Maximum: 0.05 mm (0.002 in)
3. If the clearance exceeds the maximum, replace the
connecting rod bushing.
(1) Apply engine oil to the connecting rod and the
bushing.
(2) Align the oil holes of the connecting rod and
the bushing, and press the bushing in.
(3) Correct the bushing inner diameter, so that the
clearance is within the specification, by using
a spiral expansion reamer.

76G01C-144

1C-58

1 C ASSEMBLY (CYLINDER BLOCK)
ASSEMBLY
1. Clean all parts before reinstallation.
2. Apply new engine oil to all sliding and rotating parts.
3. Replace plain bearings if they are peeling, burned, or otherwise damaged.
4. Tighten all bolts and nuts to the specified torques.
Caution
Do not reuse gaskets or oil seals.
CYLINDER BLOCK—I
Torque Specifications
69G01A-139
1C—62

ASSEMBLY (CYLINDER BLOCK) 1 C
Cavity
"F" mark
o
/-Matching mark
76G01C-147
76G01C-252
Top ring and — 90° •v. Second ring expanders. •v. Second ring
457//
iW
\ /
-J^/ \Oil ring
4BG01B-153
RF-CX RF-N
—ll Br1 &Top
GO [IP 2nd
fa? r® oil
Piston ring
Connecting Rod
1. Align the piston cavity and matching mark in the
large end of the connecting rod.
2. Apply engine oil to the circumference of each pis-
ton pin and to the small end of each connecting
rod.
3. Insert a snap ring into one of the piston pin holes
in the piston.
4. Install the piston pin using the SST.
5. Connect the piston and connecting rod by the pis-
ton pin, and lock the snap ring.
Note
Heat the piston to 50—70°C (120—170°F) for
installation.
Piston Ring
1. Apply a liberal coat of engine oil to the piston rings.
2. Install the oil ring expander and the oil ring.
3. Install the second ring.
4. Install the top ring.
5. Align the piston ring end gaps, as shown in the
figure.
Caution
The rings must be mounted so the "R" or "N"
marks face upward.
76G01C-148
1C—63

ASSEMBLY (CYLINDER BLOCK) 1 C
Cylinder block side Crankshaft side
Lower side
4BG01B-159
2. Apply engine oil to the main bearings and main
journals.
3. Install the crankshaft and bearings.
4. Install the main bearing cap according to the cap
number and mark, and tighten it evenly in or-
der shown in the figure.
5. Check that the crankshaft turns easily.
76G01C-153
6. Inspect the crankshaft end play.
End play:
0.040—0.282 mm (0.0016—0.0111 in)
Maximum: 0.30 mm (0.012 in)
76G01C-154
76G01C-155
7. If the end play is not within the specification, ad-
just the end play with an oversize thrust bearing.
Standard width:
2.00—2.05 mm (0.0787—0.0807 in)
Oversize width:
2.175—2.225 mm (0.0856—0.0876 in)
Note
First replace the rear thrust bearings, if still
not within the specification, replace the front
thrust bearings also.
1C-65

1C ASSEMBLY (CYLINDER BLOCK)
Pilot Bearing
1. Apply engine oil to the outer circumference of the
bearing.
2. Set a piece of pipe (outer diameter 30—34 mm,
1.18—1.34 in) against the outer race of the bear-
ing, then tap it evenly into the crankshaft.
3. Lubricate the bearing with grease.
76G01C-156
Piston and Connecting Rod Assembly
1. Apply a liberal amount of clean engine oil to the
cylinder walls, piston, and rings.
2. Check the piston rings for the end gap alignment.
3. Insert each piston assembly into the cylinder block
with the "F" mark facing the front of the engine.
Use a piston installer tool (commercially available).
86U01X-128
Connecting Rod Cap
1. Check the connecting rod bearing clearances us-
ing the same procedure as used for the main bear-
ing oil clearance.
Connecting rod cap tightening torque:
65—69 N-m (6.6—7.0 m-kg, 48—51 ft-lb)
Oil clearance:
0.027—0.055 mm (0.0011—0.0022 in)
Maximum: 0.08 mm (0.0031 in)
76G01C-157
Caution
Align the alignment marks on the cap and on
the connecting rod when installing the con-
necting rod cap.
If the oil clearance exceeds the maximum, grind
the crankshaft and use undersize bearings. (Re-
fer to page 1C—60.)
76G01C-158
1C-66

ASSEMBLY (CYLINDER BLOCK) 1 C
3. Check the side clearance of each connecting rod
without the cap installed.
Side clearance:
0.11—0.262 mm (0.0043—0.0103 in)
Maximum: 0.30 mm (0.012 in)
If the clearance exceeds the maximum, replace the
connecting rod.
76G01C-159
4. Apply a liberal amount of engine oil to the crank-
pin journal and connecting rod bearing.
5. Install the connecting rod cap with the alignment
marks aligned.
Tightening torque:
65—69 Nm (6.6—7.0 m-kg, 48—51 ft-lb)
86U01X-130
Oil jet
Install the oil jet into the cylinder block.
Tightening torque: 12—18 N-m
(1.2—1.8 m-kg, 104—156 in-lb)
76G01C-160
1C-67

1 C ASSEMBLY (CYLINDER BLOCK)
CYLINDER BLOCK—II
Torque Specifications
179—193 N m (18.3—19.7 m-kg, 132—142 ft-lb)
—
I iu
uii-nn, 69—95 in-tb)
69G01A-166
Rear Cover
1. Apply engine oil to the rear cover, oil seal and oil
seal lip.
2. Press the oil seal into the rear cover.
4BG01A-158
1C-68