Inspection

INSPECTION
CYLINDER HEAD DISTORTION
Head surface flatness: Less than 0.1 mm (0.004 in)
If beyond the specified limit, replace it or resurface it.
Resurfacing limit: The resurfacing limit of cylinder head is determined by the cylinder block resurfacing in an engine.
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 to make sure that camshaft rotates freely by hand. If resistance is felt, cylinder head must be replaced.
Nominal cylinder head height from camshaft center: 169.5 - 169.7 mm (6.673 - 6.681 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):
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: 40.405 - 40.595 mm (1.5907 - 1.5982 in)
Cam wear limit: 0.15 mm (0.0059 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: 28.000 - 28.021 mm (1.1024 - 1.1032 in)






3. Measure outer diameter of camshaft journal.
Standard outer diameter: 27.935 - 27.955 mm (1.0998 - 1.1006 in)
4. If clearance exceeds the limit, replace camshaft and/or cylinder head.
Camshaft journal clearance 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: 0.03 - 0.08 mm (0.0012 - 0.0031 in)

VALVE GUIDE CLEARANCE
1. Push valve stem out so that its end is even with valve guide height. Measure valve runout by moving valve.
Valve deflection limit (Dial gauge reading): 0.2 mm (0.008 in)






2. If ii exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.
b. Check that clearance is within specification.
Valve to valve guide clearance limit: 0.10 mm (0.0039in)
c. If it exceeds the limit, replace valve or valve guide.






VALVE GUIDE REPLACEMENT
1. To remove valve guide heat cylinder head to 150 to 160°C (302 to 320°F).






2. Drive out valve guide with a press [under a 20 kN (2t, 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 and Exhaust: 10.175 - 10.196 mm (0.4006 - 0.4014 in)






4. Heat cylinder head to 150 to 160°C (302 to 320°F) and press service valve guide onto cylinder head.
Projection "L": 15.1 - 15.3 mm (0.594 - 0.602 in)






VALVE SEATS
Check valve seats for evidence of pitting at valve contact surface, and reseat or replace if it is worn excessively.
- Before repairing valve seats, check valve and valve guide for wear. If they have worn, replace them. Then correct valve seat.
- Cut with both hands to assure a uniform surface.






REPLACING VALVE SEAT FOR SERVICE PARTS
1. Bore out old seat until it collapses. The machine depth stop should be set so that boring cannot continue beyond the bottom face of the seat recess in cylinder head.
2. Ream cylinder head recess.
Reaming bore for service valve seat Oversize [.5 mm (0.020 in)]:
Intake 36.500 - 36.516 mm (1.4370 - 1.4376 in)
Exhaust 32.000 - 32.016 mm (1.2598 - 1.2605 in)
Reaming should be done to the concentric circles to valve guide center so that valve seat will have the correct fit.






3. Heat cylinder head to 150 to 160°C (302 to 320°F).
4. Press fit valve seat until it seats on the bottom.






5. Cut or grind valve seat using suitable tool at the specified dimensions as shown in S.D.S. Service Data and Specification. Engine, Cooling and Exhaust
6. After cutting, lap valve seat with abrasive compound.
7. Check valve seat contact condition.






VALVE DIMENSIONS
Check dimensions in each valve. For dimensions, refer to S.D.S. Service Data and Specification. Engine, Cooling and Exhaust
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 "S" dimension.
Out-of-square:
Less than 1.8 mm (0.071 in)
2. If it exceeds the limit, replace spring.






Pressure
Check valve spring pressure.
Pressure: N (kg, lb) at height mm (in)
Standard 36.4 (54.7,120.6) at 26.5 (1.043)
Limit More than 452.79 (46.17,101.80) at 26.5 (1.043) If it exceeds the limit, replace spring.






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






2. Check diameter of valve lifter.
Outer diameter: 30.955 - 30.965 mm (1.2187 - 1.2191 in)






3. Check valve lifter guide inner diameter.
Inner diameter: 31.000 - 31.020 mm (1.2205 - 1.2213 in)
Standard clearance between valve lifter and lifter guide: 0.035 - 0.065 mm (0.0014 - 0.0026 in)