Disassembly
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DISASSEMBLY
1. REMOVE VALVE LIFTERS AND SHIMS
HINT: Arrange the valve lifters and shims in correct order.
2. REMOVE VALVES
a. Using SST, compress the valve spring and remove the 2 keepers.
SST 09202-70020 (09202-00010)
b. Remove the spring retainer, the valve spring, the valve and the spring seat.
HINT: Arrange the valves, valve springs, spring seats and spring retainers incorrect order.
c. Using needle-nose pliers, remove the oil seal.
INSPECTION
1. CLEAN TOP SURFACES OF PISTONS AND CYLINDER BLOCK
a. Turn the crankshaft, and bring each piston to top dead center (TDC). Using a gasket scraper, remove all the carbon from the piston top surface.
b. Using a surface contacting gasket scraper, remove all the gasket materials from the cylinder block.
c. Using compressed air, blow carbon and oil from the bolt holes.
CAUTION: Protect your eyes when using high pressure compressed air.
2. REMOVE GASKET MATERIAL
Using a gasket scraper, remove all the gasket material from the cylinder block contact surface.
NOTICE: Be careful not to scratch the surface contacting the cylinder block.
3. CLEAN COMBUSTION CHAMBERS
Using a wire brush, remove all the carbon from the combustion chambers.
NOTICE: Be careful not to scratch the surface contacting the cylinder block.
4. CLEAN VALVE GUIDE BUSHINGS
Using a valve guide bushing brush and solvent, clean all the guide bushings.
5. CLEAN CYLINDER HEAD
Using a soft brush and solvent, thoroughly clean the cylinder head.
6. INSPECT FOR FLATNESS
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.
7. INSPECT FOR CRACKS
Using a dye penetrant, check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks. If cracked, replace the cylinder head.
8. CLEAN VALVES
a. Using a gasket scraper, chip off any carbon from the valve head.
b. Using a wire brush, thoroughly clean the valve.
9. INSPECT VALVE STEMS AND GUIDE BUSHINGS
a. Using a caliper gauge, measure the inside diameter of the guide bushing.
Bushing inside diameter: 5.510 - 5.530 mm (0.2169 - 0.2177 inch)
b. Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter
c. Subtract the valve stem diameter measurement from the guide bushing inside diameter measurement.
Standard oil clearance
Maximum oil clearance
If the clearance is greater than maximum, replace the valve and guide bushing.
10. INSPECT AND GRIND VALVES
a. Grind the valve enough to remove pits and carbon.
b. Check that the valve is ground to the correct valve face angle.
Valve face angle: 44.5°
c. Check the valve head margin thickness.
Standard margin thickness: 1.00 mm (0.039 inch)
Minimum margin thickness: 0.5 mm (0.020 inch)
If the margin thickness is less than minimum, replace the valve.
d. Check the valve overall length.
Standard overall length
Minimum overall length
If the overall length is less than minimum, replace the valve.
e. 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.
11. INSPECT AND CLEAN VALVE SEATS
a. Using a 45° carbide cutter, resurface the valve seats. Remove only metal enough to clean the seats.
b. Check the valve seating position.
Apply a light coat of prussian blue (or white lead) to the valve face. Lightly press the valve against the seat. Do not rotate the valve.
c. Check the valve face and seat for the following:
- If blue appears 360° around the face, the valve is concentric. If not, replace the valve.
- If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the seat.
- Check that the seat contact is in the middle of the valve face with the following width:
1.0 - 1.4 mm (0.039 - 0.055 inch)
If not, correct the valve seats as follows:
1. If the seating is too high on the valve face, use 30° and 45° cutters to correct the seat.
2. If the seating is too low on the valve face, use 60° and 45° cutters to correct the seat.
d. Hand-lap the valve and valve seat with an abrasive compound.
e. After hand-lapping, clean the valve and valve seat.
12. INSPECT VALVE SPRINGS
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 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:
204 - 226 N (20.8 - 23.0 kgf, 45.9 - 50.7 lbs.) at 35.0 mm (1.378 inch)
If the installed tension is not as specified, replace the valve spring.
13. INSPECT CAMSHAFT FOR RUNOUT
a. Place the camshaft on V-blocks.
b. Using a dial indicator, measure the circle runout at the center journal.
Maximum circle runout: 0.08 mm (0.0031 inch)
If the circle runout is greater than maximum, replace the camshaft.
14. INSPECT CAM LOBES
Using a micrometer, measure the cam lobe height.
Standard cam lobe height
Minimum cam lobe height
If the cam lobe height is less than minimum, replace the camshaft.
15. INSPECT CAMSHAFT JOURNALS
Using a micrometer, measure the journal diameter.
Journal diameter: 26.954 - 26.970 mm (1.0612 - 1.0618 inch)
If the journal diameter is not as specified, check the oil clearance.
16. INSPECT CAMSHAFT GEAR SPRING
Using vernier calipers, measure the free distance between the spring ends.
Free distance: 18.2 - 18.8 mm (0.712 - 0.740 inch)
If the free distance is not as specified, replace the gear spring.
17. INSPECT CAMSHAFT BEARINGS
Check that bearings for flaking and scoring. If the bearings are damaged, replace the bearing caps and cylinder head as a set.
18. INSPECT CAMSHAFT JOURNAL OIL CLEARANCE
a. Clean the bearing caps and camshaft journals.
b. Place the camshafts on the cylinder head.
c. Lay a strip of Plastigage across each of the camshaft journals.
d. Install the bearing caps.
NOTICE: Do not turn the camshaft.
e. Remove the bearing caps.
f. Measure the Plastigage at its widest point.
Maximum oil clearance: 0.10 mm (0.0039 inch)
If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
g. Completely remove the plastigage.
h. Remove the camshafts.
19. 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: 0.12 mm (0.0047 inch)
If the thrust clearance is greater than maximum, replace the camshaft.
If necessary, replace the bearing caps and cylinder head as a set.
c. Remove the camshafts.
20. INSPECT CAMSHAFT GEAR BACKLASH
a. Install the camshafts without installing the exhaust cam sub-gear and front bearing cap.
b. Using a dial indicator, measure the backlash.
Standard backlash: 0.020 - 0.200 mm (0.0008 - 0.0079 inch)
Maximum backlash: 0.30 mm (0.0188 inch)
If the backlash is greater than maximum, replace the camshafts.
c. Remove the camshafts.
21. INSPECT VALVE LIFTERS AND LIFTER BORES
a. 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)
b. Using a micrometer, measure the lifter diameter at the valve lifter center line, 12.3 - 12.7 mm (0.484 - 0.500 inch) from the valve lifter head.
Lifter diameter: 30.966 - 30.976 mm (1.2191 - 1.2195 inch)
c. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.024 - 0.050 mm (0.0009 - 0.0020 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.
22. INSPECT INTAKE MANIFOLD
a. Upper Intake Manifold:
Using a precision straight edge and feeler gauge, measure the surface contacting the lower intake manifold for warpage.
Maximum warpage: 0.15 mm (0.0059 inch)
If warpage is greater than maximum, replace the upper intake manifold.
b. Lower Intake Manifold:
Using a precision straight edge and feeler gauge, measure the surface contacting the cylinder head and upper intake manifold for warpage.
Maximum warpage: 0.15 mm (0.0059 inch)
If warpage is greater than maximum, replace the lower intake manifold.
23. INSPECT EXHAUST MANIFOLDS
Using a precision straight edge and feeler gauge, measure the surface contacting the cylinder head for warpage.
Maximum warpage: 0.50 mm (0.0197 inch)
If warpage is greater than maximum, replace the manifold.
24. INSPECT CYLINDER HEAD BOLTS
Using vernier calipers, measure the thread outside diameter of the bolt.
Standard outside diameter: 9.810 - 9.960 mm (0.3862 - 0.3921 inch)
Minimum outside diameter: 9.700 mm (0.3819 inch)
If the diameter is less than minimum, replace the bolt.
REPLACEMENT
1. REPLACE VALVE GUIDE BUSHINGS
a. Gradually heat the cylinder head to 80 - 100°C (176 - 212°F).
b. Using SST and a hammer, tap out the guide bushing.
SST 09201-10055, 09950-70010 (09951-07100)
c. Using a caliper gauge, measure the bushing bore diameter of the cylinder head.
d. Select a new guide bushing (STD or O/S 0.05).
If the bushing bore diameter of the cylinder head is greater than 10.306 mm (0.4057 inch), machine the bushing bore to the following dimension:
10.335 - 10.356 mm (0.4069 - 0.4077 inch)
If the bushing bore diameter of the cylinder head is greater than 10.356 mm (0.4077 inch), replace the cylinder head.
HINT: Different the bushings are used for the intake and exhaust.
e. Gradually heat the cylinder head to 80 - 100°C (176 - 212°F).
f. Using SST and a hammer, tap in a new guide bushing to the specified protrusion height.
Protrusion height
SST 09201-10055, 09950-70010 (09951-07100)
g. Using a sharp 5.5 mm reamer, ream the guide bushing to obtain the standard specified clearance between the guide bushing and valve stem.
2. REPLACE SPARK PLUG TUBE GASKETS
a. Bend the 4 ventilation case claws installed on the cylinder head cover to an angle of 90° or more.
b. Using a screwdriver, pry out the gasket.
NOTICE: Be careful not to damage the cylinder head cover. Tape the screwdriver tip.
c. Using SST and a hammer, tap in a new gasket until its surface is flush with the upper edge of the cylinder head cover.
SST 09950-60010 (09551-00240, 09951-00440, 09952-06010), 09950-70010 (09951-07100)
NOTICE: Be careful of the installation direction.
d. Apply a light coat of MP grease to the gasket lip.
e. Return the 4 ventilation case claws to its original position.