Disassembly, Inspection and Assembly

Legend
1 Oil filler cap
2 Rocker cover
3 Rocker cover gasket
4 Oil seal
5 Camshaft bracket
6 Intake camshaft
7 Exhaust camshaft
8 Distributor bracket
9 Cylinder head bolt
10 Shim
11 Valve litter
12 Valve cotter
13 Valve spring retainer
14 Valve spring
15 Valve spring seat
16 Valve oil seal
17 Valve guide
18 Cylinder head
19 Cylinder head gasket
20 Valve seat
21 Valve
22 Cylinder head front cover

DISASSEMBLY
1. Remove valve components with Tool.
2. Remove valve oil seal with a suitable tool.

INSPECTION
CYLINDER HEAD DISTORTION
Clean surface of cylinder head.
Use a reliable straightedge and feeler gauge to check the flatness of cylinder head surface.
Check along six positions shown in image.
Head surface flatness:
Standard: Less than 0.03 mm (0.0012 in)
Limit: 0.1 mm (0.004 in)

If beyond the specified limit, replace it or resurface it.

Resurfacing limit:
The limit for cylinder head resurfacing is determined by the amount of cylinder block resurfacing.
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit is as follows:
A + B = 0.2 mm (0.008 in)

After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, replace cylinder head.
Nominal cylinder head height:
117.8 - 118.0 mm (4.638 - 4.646 in)

CAMSHAFT VISUAL CHECK
Check camshaft for scratches, seizure and wear.

CAMSHAFT RUNOUT
1. Measure camshaft runout at the center journal.
Runout (Total indicator reading):
Standard:
Less than 0.02 mm (0.0008 in)
Limit:
0.1 mm (0.004 in)

2. If it exceeds the limit, replace camshaft.

CAMSHAFT CAM HEIGHT
1. Measure camshaft cam height.
Standard cam height:
Intake
40.610 - 40.800 mm (1.5988 - 1.6063 in)
Exhaust
39.910 - 40.100 mm (1.5713 - 1.5787 in)
Cam wear limit:
0.20 mm (0.0079 in)

2. If wear is beyond the limit, replace camshaft.

CAMSHAFT JOURNAL CLEARANCE
1. Install camshaft bracket and tighten bolts to the specified torque.
2. Measure inner diameter of camshaft bearing.
Standard inner diameter:
No.1 bearing
28.000 - 28.021 mm (1.1024 - 1.1032 in)
No.2 to No.5 bearings
24.000 - 24.021 mm (0.9449 - 0.9457 in)

3. Measure outer diameter of camshaft journal.
Standard outer diameter:
No.1 journal
27.935 - 27.955 mm (1.0998 - 1.1006 in)
No.2 to No.5 journals
23.935 - 23.955 mm (0.9423 - 0.9431 in)

4. If clearance exceeds the limit, replace camshaft and/or cylinder head.
Camshaft journal clearance:
Standard 0.045 - 0.086 mm (0.0018 - 0.0034 in)
Limit 0.15 mm (0.0059 in)

CAMSHAFT END PLAY
1. Install camshaft in cylinder head.
2. Measure camshaft end play.
Camshaft end play:
Standard
0.115 - 0.188 mm (0.0045 - 0.0074 in)
Limit
0.20 mm (0.0079 in)

3. If limit is exceeded, replace camshaft and remeasure end play.
- If limit is still exceeded after replacing camshaft, replace cylinder head.

CAMSHAFT SPROCKET RUNOUT
1. Install sprocket on camshaft.
2. Measure camshaft sprocket runout.
Runout (Total indicator reading):
Limit 0.15 mm (0.0071 in)

3. If it exceeds the limit, replace camshaft sprocket.

VALVE GUIDE CLEARANCE
1. Measure valve deflection as shown in image. (Valve and valve guide mostly wear in this direction.)
Valve deflection limit (Dial gauge reading):
Intake & Exhaust 0.2 mm (0.008 in)

2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.
b. Calculate valve to valve guide clearance.

Valve to valve guide clearance = valve guide inner diameter - valve stem diameter:

c. Check that clearance is within specification.
- If it exceeds the limit, replace valve and remeasure clearance.
- If limit is still exceeded after replacing valve, replace valve guide.

VALVE GUIDE REPLACEMENT
1. To remove valve guide, heat cylinder head to 110 to 1 20°C (230 to 248°F).

2. Drive out valve guide with a press [under a 20 kN (2 ton, 2.2 US ton, 2.0 Imp ton) pressure] or hammer and suitable tool.

3. Ream cylinder head valve guide hole.
Valve guide hole diameter (for service parts):
Intake & Exhaust
9.685 - 9.696 mm (0.3813 - 0.3817 in)

4. Heat cylinder head to 110 to 120°C (230 to 248°F) and press service valve guide into cylinder head.
Projection "L":
11.5 - 11.7 mm (0.453 - 0.461 in)

5. Ream valve guide.
Finished size:
Intake & Exhaust
5.500 - 5.515 mm (0.2165 - 0.2171 in)

VALVE SEATS
Check valve seats for pitting at contact surface. Resurface or replace if excessively worn.
- Before repairing valve seats, check valve and valve guide for wear. If they have worn, replace them. Then correct valve seat.
- Use both hands to cut uniformly.

REPLACING VALVE SEAT FOR SERVICE PARTS
1. Bore out old seat until it collapses. Set machine depth stop so that boring cannot contact the bottom face of seat recess in cylinder head.
2. Ream cylinder head recess.
Reaming bore for service valve seat Oversize [0.5 mm (0.020 in)]:
Intake 31.500 - 31.516 mm (1.2402 - 1.2408 in)
Exhaust 26.500 - 26.516 mm (1.0433 - 1.0439 in)

Use the valve guide center for reaming to ensure valve seat will have the correct fit.

3. Heat cylinder head to 110 to 120°C (230 to 248°F).
4. Press fit valve seat until it seats on the bottom.

5. Cut or grind valve seat using suitable tool to the specified dimensions as shown in Specifications.
6. After cutting, lap valve seat with abrasive compound.
7. Check valve seating condition.
Seatface angle:
45° 15' - 45° 45' deg.
Contacting width "W":
Intake
1.06-1.34 mm (0.0417 - 0.0528 in)
Exhaust
1.20-1.68 mm (0.0472 - 0.0661 in)

VALVE DIMENSIONS
Check dimensions of each valve. Refer to Specifications.

When valve head has been worn down to 0.5 mm (0.020 in) in margin thickness, replace valve.
Grinding allowance for valve stem tip is 0.2 mm (0.008 in) or less.

VALVE SPRING
Squareness
1. Measure dimension "S".
Out-of-square "S":
Less than 1.80 mm (0.0709 in)

2. If it exceeds the limit, replace spring.

Pressure
Check valve spring pressure at specified spring height.
Pressure:
Standard
344.42 N (35.12 kg, 77.44 lb) at 25.26 mm (0.9945 in)
Limit
More than 330.41 N (33.69 kg, 74.31 lb) at 23.64 mm (0.9307 in)

If it exceeds the limit, replace spring.

VALVE LIFTER
1. Check contact and sliding surfaces for wear or scratches.

2. Check diameter of valve lifter and valve lifter guide bore.
Valve lifter diameter:
29.960 - 29.975 mm (1.1795 - 1.1801 in)

Lifter guide bore diameter:
30.000 - 30.021 mm (1.1811 - 1.1819 in)
Clearance between valve lifter and valve lifter guide:
0.025 - 0.061 mm (0.0010 - 0.0024 in)

If it exceeds the limit, replace valve lifter or cylinder head which exceeds the standard diameter tolerance.

Assembly
1. Install valve component parts.
- Always use new valve oil seal.
- Before installing valve oil seal, install valve spring seat.
- After installing valve components, tap valve stem tip with a plastic hammer to assure a proper fit.

- Install Type A valve spring (narrow pitch at one end of spring only) with narrow pitch end toward cylinder head.

- Install Type B valve spring (narrow pitch at both ends of spring) with either end toward cylinder head.