Part 1
OVERHAUL1. REMOVE VALVE LIFTER
a. Remove the valve lifter and adjusting shim.
HINT: Arrange the valve lifters and shims in correct order.
2. REMOVE INTAKE VALVE
a. Using SST, compress the compression spring and remove the 2 keepers.
SST 09202-70020 (09202-00010)
b. Remove the spring retainer, compression spring, valve and spring seat.
HINT: Arrange the valves, compression springs, spring seats and spring retainers incorrect order.
3. REMOVE EXHAUST VALVE
a. Using SST, compress the compression spring and remove the 2 keepers.
SST 09202-70020 (09202-00010)
b. Remove the spring retainer, compression spring, valve and spring seat.
HINT: Arrange the valves, compression springs, spring seats and spring retainers incorrect order.
4. REMOVE VALVE STEM OIL O-SEAL OR RING
a. Using needle-nose pliers, remove the oil seal.
5. INSPECT CYLINDER HEAD SUB-ASSY
a. Clean the cylinder head.
1. Using a gasket scraper, remove all the gasket material from the cylinder block contact surface.
NOTICE: Be careful not to scratch the cylinder block contact surface.
2. Using a wire brush, remove all the carbon from the combustion chambers.
NOTICE: Be careful not to scratch the cylinder block contact surface.
3. Using a valve guide bushing brush and solvent, clean all the guide bushes.
4. Using a soft brush and solvent, thoroughly clean the cylinder head.
b. Inspect for flatness.
1. Using a precision straight edge and feeler gauge, measure the surfaces contacting the cylinder block and the manifolds for warpage.
Maximum warpage: 0.10 mm (0.0039 inch)
If warpage is greater than maximum, replace the cylinder head.
c. Inspect for cracks.
1. Using a dye penetrant, check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks.
If cracked, replace the cylinder head.
6. INSPECT INTAKE VALVE
a. Clean the valves.
1. Using a gasket scraper, chip off any carbon from the valve head.
2. Using a wire brush, thoroughly clean the valve.
b. Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter: 5.470 - 5.485 mm (0.2154 - 2.2159 inch)
c. Check the valve face angle.
1. Grind the valve enough to remove pits and carbon.
2. Check that the valve is ground to the correct valve face angle.
Valve face angle: 44.5°
d. Check the valve head margin thickness.
Standard margin thickness: 1.0 mm (0.039 inch)
Minimum margin thickness: 0.5 mm (0.020 inch)
If the margin thickness is less than minimum, replace the valve.
e. Check the valve overall length.
Standard overall length: 94.80 - 95.30 mm (3.7323 - 3.7520 inch)
Minimum overall length: 94.55 mm (3.7224 inch)
If the overall length is less than minimum, replace the valve.
f. Check the surface of the valve stem tip for wear. If the valve stem tip is worn, resurface the tip with a grinder or replace the valve.
NOTICE: Do not grind off more than minimum.
7. INSPECT EXHAUST VALVE
a. Clean the valves.
1. Using a gasket scraper, chip off any carbon from the valve head.
2. Using a wire brush, thoroughly clean the valve.
b. Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter: 5.465 - 5.480 mm (0.2152 - 2.2157 inch)
c. Check the valve face angle.
1. Grind the valve enough to remove pits and carbon.
2. Check that the valve is ground to the correct valve face angle.
Valve face angle: 44.5°
d. Check the valve head margin thickness.
Standard margin thickness: 1.0 mm (0.039 inch)
Minimum margin thickness: 0.5 mm (0.020 inch)
If the margin thickness is less than minimum, replace the valve
e. Check the valve overall length.
Standard overall length: 94.85 - 95.35 mm (3.7342 - 3.7539 inch)
Minimum overall length: 94.60 mm (3.7244 inch)
If the overall length is less than minimum, replace the valve.
f. Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, resurface the tip with a grinder or replace the valve.
NOTICE: Do not grind off more than minimum.
8. INSPECT INNER COMPRESSION SPRING
a. Using a steel square, measure the deviation of the spring.
Maximum deviation: 2.0 mm (0.079 inch)
If the deviation is greater than maximum, replace the spring.
b. Using vernier calipers, measure the free length of the spring.
Free length: 54.05 - 54.15 mm (2.1279 - 2.1319 inch)
If the free length is not as specified, replace the spring.
c. Using a spring tester, measure the tension of the valve spring at the specified installed length.
Installed tension: 210 - 226 N (20.8 - 23.0 kgf, 45.9 - 50.7 lbs) at 35.04 mm (1.3795 inch)
If the installed tension is not as specified, replace the valve spring.
9. INSPECT INTAKE VALVE GUIDE BUSH
a. Using a caliper gauge, measure the inside diameter of the guide bush.
Bush inside diameter: 5.510 - 5.530 mm (0.2169 - 0.2177 inch)
b. Subtract the valve stem diameter measurement (See step 6) from the guide bush inside diameter measurement.
Standard oil clearance: 0.025 - 0.060 mm (0.0010 - 0.0024 inch)
Maximum oil clearance: 0.08 mm (0.0031 inch)
If the clearance is greater than maximum, replace the valve and guide bush (See steps 11 and 13).
10. INSPECT EXHAUST VALVE GUIDE BUSH
a. Using a caliper gauge, measure the inside diameter of the guide bush.
Bush inside diameter: 5.510 - 5.530 mm (0.2169 - 0.2177 inch)
b. Subtract the valve stem diameter measurement (See step 7) from the guide bush inside diameter measurement.
Standard oil clearance: 0.030 - 0.065 mm (0.0012 - 0.0026 inch)
Maximum oil clearance: 0.10 mm (0.0039 inch)
If the clearance is greater than maximum, replace the valve and guide bush (See steps 12 and 14).
11. REMOVE INTAKE VALVE GUIDE BUSH
a. Gradually heat the cylinder head to 80 - 100°C (176 - 212°F).
b. Using SST and a hammer, tap out the guide bush.
SST 09201-01055, 09950-70010 (09951-07100)
12. REMOVE EXHAUST VALVE GUIDE BUSH
a. Gradually heat the cylinder head to 80 - 100°C (176 - 212°F)
b. Using SST and a hammer, tap out the guide bush.
SST 09201-01055, 0995-70010 (09951-07100)
13. INSTALL INTAKE VALVE GUIDE BUSH
a. Using a caliper gauge, measure the bush bore diameter of the cylinder head.
b. Select a new guide bush (STD or O/S 0.05).
Bush bore diameter Bush size
If the bush bore diameter of the cylinder head is greater than 10.306 mm (0.4057 inch), machine the bush bore to this dimension of 10.335 - 10.356 mm (0.4068 - 0.4077 inch).
If the bush bore diameter of the cylinder head is greater than 10.356 mm (0.4077 inch), replace the cylinder head.
HINT: Different the bushes are used for the intake and exhaust.
c. Gradually heat the cylinder head to 80 - 100°C (176 - 212°F).
d. Using SST and a hammer, tap in a new guide bush to the specified protrusion height.
SST 09201-01055, 09950-70010 (09951-07100)
Protrusion height (H): 9.2 - 9.8 mm (0.362 - 0.386 inch)
e. Using a sharp 5.5 mm reamer, ream the guide bush to obtain the standard specified clearance (See step 9) between the guide bush and valve stem.
14. INSTALL EXHAUST VALVE GUIDE BUSH
a. Using a caliper gauge, measure the bush bore diameter of the cylinder head.
b. Select a new guide bush (STD or O/S 0.05).
If the bush bore diameter of the cylinder head is greater than 10.306 mm (0.4057 inch), machine the bush bore to this dimension of 10.335 - 10.356 mm (0.4068 - 0.4077 inch).
If the bush bore diameter of the cylinder head is greater than 10.356 mm (0.4077 inch), replace the cylinder head.
HINT: Different the bushes are used for the intake and exhaust.
c. Gradually heat the cylinder head to 80 - 100°C (176 - 212°F).
d. Using SST and a hammer, tap in a new guide bush to the specified protrusion height.
SST 09201-01055, 0995-70010 (09951-07100)
Protrusion height (H): 8.2 - 8.8 mm (0.323 - 0.346 inch)
e. Using a sharp 5.5 mm reamer, ream the guide bush to obtain the standard specified clearance (See step 10) between the guide bush and valve stem.
15. INSPECT INTAKE VALVE SEAT
a. Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats.
b. Check the valve seating position.
1. Apply a light coat of Prussian blue (or white lead) to the valve face.
2. Lightly press the valve against the seat. Do not rotate valve.
c. Check the valve face and seat for the following:
1. If blue appears 360° around the face, the valve is concentric. If not, replace the valve.
2. If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the seat.
3. Check that the seat contact is in the middle of the valve face with these width:
Width: 1.0 - 1.4 mm (0.039 - 0.055 inch)
16. INSPECT EXHAUST VALVE SEAT
a. Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats.
b. Check the valve seating position.
1. Apply a light coat of Prussian blue (or white lead) to the valve face.
2. Lightly press the valve against the seat. Do not rotate valve.
c. Check the valve face and seat for the following:
1. If blue appears 360° around the face, the valve is concentric. If not, replace the valve.
2. If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the seat.
3. Check that the seat contact is in the middle of the valve face with these width:
Width: 1.0 - 1.4 mm (0.039 - 0.055 inch)
17. REPAIR INTAKE VALVE SEAT
a. If the seating is too high on the valve face:
Use 30° and 45° cutters to correct the seat.
b. If the seating is too low on the valve face:
Use 60° and 45° cutters to correct the seat.
c. Hand-lap the valve and valve seat with an abrasive compound.
d. After hand-lapping, clean the valve and valve seat.
18. REPAIR EXHAUST VALVE SEAT
a. If the seating is too high on the valve face:
Use 30° and 45° cutters to correct the seat.
b. If the seating is too low on the valve face:
Use 60° and 45° cutters to correct the seat.
c. Hand-lap the valve and valve seat with an abrasive compound.
d. After hand-lapping, clean the valve and valve seat.
19. INSPECT VALVE LIFTER
a. Using a micrometer, measure the lifter diameter at the 12.5 ± 2.0 mm (0.492 ± 0.079 inch) from the top surface.
Lifter diameter: 30.968 - 30.976 mm (1.2192 - 1.2195 inch)
b. Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Lifter bore diameter: 31.000 - 31.016 mm (1.2205 - 1.2211 inch)
c. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.024 - 0.048 mm (0.0009 - 0.0018 inch)
Maximum oil clearance: 0.07 mm (0.0028 inch)
If the oil clearance is greater than maximum, replace the lifter.
If necessary, replace the cylinder head.