Overhaul

OVERHAUL

HINT:
- Thoroughly clean all parts to be assembled.
- Before installing the parts, apply new engine oil to all sliding and rotating surfaces.
- Replace all gaskets, O-rings and oil seals with new ones.

1. 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 valve spring and remove the 2 valve spring retainer locks.
SST 09202-70020 (09202-01010)
b. Remove the spring retainer, valve spring, valve and spring seat.

HINT: Arrange the valves, valve springs, spring seats and spring retainers in correct order.





3. REMOVE EXHAUST VALVE
a. Using SST, compress the valve spring and remove the 2 valve spring retainer locks.
SST 09202-70020 (09202-00010)
b. Remove the spring retainer, valve spring, valve and spring seat.

HINT: Arrange the valves, valve springs, spring seats and spring retainers in correct order.





4. REMOVE VALVE STEM OIL SEAL
a. Using needle-nose pliers, remove the oil seal.





5. INSPECT CYLINDER HEAD SUB-ASSEMBLY
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 warpage.
1 Using a precision straight edge and feeler gauge, measure the warpage of the contact surfaces of the cylinder block and the manifolds.
Maximum warpage: 0.10 mm (0.0039 inch)
If warpage is greater than the 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 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:
Intake: 5.470 to 5.485 mm (0.2154 to 0.2159 inch)
Exhaust: 5.465 to 5.480 mm (0.2152 to 0.2157 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:
Intake: 1.25 mm (0.049 inch)
Exhaust: 1.4 mm (0.055 inch)
Minimum margin thickness: 0.5 mm (0.020 inch)
If the margin thickness is less than the minimum, replace the valve.





e. Check the valve overall length.
Standard overall length:
Intake: 95.05 mm (3.7421 inch)
Exhaust: 95.10 mm (3.7441 inch)
Minimum overall length:
Intake: 94.55 mm (3.7224 inch)
Exhaust: 94.60 mm (3.7244 inch)
If the overall length is less than the 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 the minimum.

7. INSPECT VALVE SPRING





a. Using a steel square, measure the deviation of the valve spring.
Maximum deviation: 2.0 mm (0.079 inch)
If the deviation is greater than the maximum, replace the valve spring.





b. Using vernier calipers, measure the free length of the valve spring.
Free length: 54.1 mm (2.130 inch)
If the free length is not as specified, replace the valve spring.





c. Using a spring tester, measure the tension of the valve spring at the specified installed length.
Installed tension: 210 to 226 N (21.4 to 23.0 kgf, 47.2 to 50.7 ft. lbs.) at 35.0 mm (1.378 inch)
If the installed tension is not as specified, replace the valve spring.





8. INSPECT VALVE GUIDE BUSH
a. Using a caliper gauge, measure the inside diameter of the guide bush.
Bush inside diameter: 5.510 to 5.530 mm (0.2169 to 0.2177 inch)
b. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
Standard oil clearance:
Intake: 0.025 to 0.060 mm (0.0010 to 0.0024 inch)
Exhaust: 0.030 to 0.065 mm (0.0012 to 0.0026 inch)
Maximum oil clearance:
Intake: 0.08 mm (0.0031 inch)
Exhaust: 0.10 mm (0.0039 inch)
If the clearance is greater than the maximum, replace the valve and guide bush.
9. REMOVE VALVE GUIDE BUSH





a. Gradually heat the cylinder head to 80 to 100°C (176 to 212°F).





b. Using SST and a hammer, tap out the guide bush.
SST 09201-10000 (09201-01060), 09950-70010 (09951-07100)
10. INSTALL 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 so that the dimension is between 10.335 and 10.356 mm (0.4069 and 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 bushes are used for the intake and exhaust.





c. Gradually heat the cylinder head to 80 to 100°C (176 to 212°F).
d. Using SST and a hammer, tap in a new guide bush to the specified protrusion height.
Protrusion height:
Intake: 9.2 to 9.8 mm (0.362 to 0.386 inch)
Exhaust: 8.2 to 8.8 mm (0.323 to 0.346 inch)





e. Using a sharp 5.5 mm reamer, ream the guide bush to obtain the specified clearance between the guide bush and valve stem.
SST 09201-10000 (09201-01060), 09950-70010 (09951-07100)
11. INSPECT VALVE SEAT





a. Using a 45° carbide cutter, resurface the valve seats. Clean metal filings from the valve 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 Prussian blue appears around the entire face, the valve is centered. If not, replace the valve.
2 If Prussian blue appears around the entire valve seat, the guide and face are centered. If not, resurface the seat.
3 Check that the seat contacts in the middle of the valve face with the the following width:
Width: 1.0 to 1.4 mm (0.039 to 0.055 inch)
12. REPAIR 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 rub the valve and valve seat with an abrasive compound.
d. After hand-rubbing, clean the valve and valve seat.
13. INSPECT VALVE LIFTER





a. Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Lifter bore diameter: 31.000 to 31.016 mm (1.2205 to 1.2211 inch)





b. Using a micrometer, measure the lifter diameter where the distance from the top surface is 12.3 to 12.7 mm (0.484 to 0.500 inch).
Lifter diameter: 30.968 to 30.976 mm (1.2192 to 1.2195 inch)
c. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.024 to 0.050 mm (0.0009 to 0.0020 inch)
Maximum oil clearance: 0.07 mm (0.0028 inch)
If the oil clearance is greater than the maximum, replace the lifter. If necessary, replace the cylinder head.
14. INSPECT CAMSHAFT OIL CLEARANCE





a. Install the camshaft timing tube to the camshaft.
b. Clean the bearing caps and camshaft journals.
c. Check the bearings for flaking and scoring.
If the bearings are damaged, replace the bearing caps and cylinder head as a set.
d. Place the camshafts on the cylinder head.
e. Lay a strip of Plastigage across each of the camshaft journals.





f. Install the bearing caps.
Torque:
7.5 Nm (76 kgf-cm, 66 ft. lbs.) for bolt A
16 Nm (163 kgf-cm, 12 ft. lbs.) for others

NOTICE: Do not turn the camshaft.

g. Remove the bearing caps.





h. Measure the Plastigage at its widest point.





Standard oil clearance





Maximum oil clearance

If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
i. Remove the camshafts.
j. Completely remove the Plastigage.
15. INSPECT CAMSHAFT THRUST CLEARANCE





a. Install the camshaft.
b. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.





Standard thrust clearance





Maximum thrust clearance

If the thrust clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
c. Remove the camshafts.
d. Remove the camshaft timing tube from the intake camshaft.





16. INSPECT CAMSHAFT GEAR BACKLASH
a. Install the drive gear to the camshaft timing tube.
b. Install the camshaft timing tube to the intake camshaft.
c. Install the camshafts without installing the exhaust camshaft sub-gear No.3 and front bearing cap.
d. Using a dial indicator, measure the backlash.
Standard backlash: 0.020 to 0.200 mm (0.0008 to 0.0079 inch)
Maximum backlash: 0.30 mm (0.0118 inch)
If the backlash is greater than the maximum, replace the intake camshaft drive gear and exhaust camshaft.
e. Remove the camshafts.
f. Remove the camshaft timing tube from the intake camshaft.
g. Remove the drive gear from the camshaft timing tube.





17. INSTALL TIGHT PLUG NO.1
a. Apply adhesive to the tight plug.
Adhesive: Part No. 08833-00070, THREE BOND 1324 or equivalent
b. Using SST and a hammer, tap in a new tight plug as shown in the illustration.
SST 09950-60010 (09951-00300), 09950-70010 (09951-07100)





18. INSTALL CAMSHAFT BEARING CAP SETTING RING PIN





19. INSTALL STUD BOLT
20. INSTALL VALVE STEM OIL SEAL





a. Apply a light coat of engine oil to a new oil seal.

NOTICE: Pay close attention when installing the intake and exhaust oil seals. For example, installing the intake oil seal into the exhaust or installing the exhaust oil seal to the intake can cause installation problems later.

HINT: The intake valve oil seal is gray/brown and the exhaust valve oil seal is black/gray.





b. Using SST, push in a new oil seal.
SST 09201-41020

NOTICE: Failure to use SST will cause the seal to be damaged or improperly seated.

21. INSTALL VALVE





a. Install the following parts:
1 Valve
2 Spring seat
3 Valve spring
4 Spring retainer





b. Using SST, compress the valve spring and place the 2 spring retainer locks around the valve stem.
SST 09202-70020 (09202-00010)





c. Using a plastic hammer and the valve stem (not in use) tip wrapped with vinyl tape, lightly tap the valve stem tip to assure proper fit.

NOTICE: Be careful not do damage the valve stem tip.

22. INSTALL VALVE LIFTER
a. Install the valve lifter and shim.
b. Check that the valve lifter rotates smoothly by hand.