Dissemble
Disassembly Of Cylinder HeadCylinder Head Components:
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 two keepers. SST 09202-70010.
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.
c. Using needle-nose pliers, remove the oil seal.
3. Remove wire harness protector bracket.
4. Remove no.2 engine hanger.
5. Remove no.1 engine hanger.
6. Remove half circular plug.
7. Remove the two bolts and No.4 camshaft bearing cap.
Inspection, Cleaning and Repair of Cylinder Head Components
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 surfaces.
b. Using a gasket scraper, remove all the gasket material from the top surface of 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. Clean cylinder head.
a. Using a gasket scraper, remove all the gasket material from the cylinder block surface.
NOTICE: Be careful not to scratch the cylinder block contact surface.
b. Using a wire brush, remove all the carbon from the combustion chambers.
NOTICE: Be careful not to scratch the cylinder block contact surface.
c. Using a valve guide bushing brush and solvent, clean all the guide bushings.
d. Using a soft brush and solvent, thoroughly clean the cylinder head.
3. Inspect cylinder head.
a. Inspect for flatness. Using precision straight edge and feeler gauge, measure the surfaces contacting the cylinder block and manifolds for warpage.
Maximum warpage:
Cylinder block side 0.05 mm (0.0020 in.)
Manifold side 0.05 mm (0.0020 in.)
If warpage is greater than maximum, replace the cylinder head.
b. Inspect for cracks. Using a dye penetrant, check the combustion chambers, intake ports, exhaust ports and cylinder block surface for cracks. If cracked, replace the cylinder head.
4. Clean valves.
a. Using a gasket scraper, chip off any carbon from the valve head.
b. Using a wire brush, thoroughly clean the valve.
5. Inspect valve stems and guide bushings.
a. Using a caliper gauge, measure the inside diameter of the guide bushing.
Bushing inside diameter:
6.010 - 6.030 mm (0.2366 - 0.2374 in.)
b. Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter:
Intake 5.970 - 5.985 mm (0.2350 - 0.2356 in.)
Exhaust 5.965 - 5.980 mm (0.2348 - 0.2354 in.)
c. Subtract the valve stem diameter measurement from the guide bushing inside diameter measurement.
Standard oil clearance:
Intake 0.025-0.060 mm (0.0010 - 0.0024 in.)
Exhaust 0.030 - 0.065 mm (0.0012-0.0026 in.)
Maximum oil clearance:
Intake 0.08 mm (0.0031 in.)
Exhaust 0.10 mm (0.0039 in.)
If the clearance is greater than maximum, replace the valve and guide bushing.
6. If necessary, replace valve guide bushings.
a. Using SST and a hammer, tap out the guide bushing. SST 09201-70010.
b. Using a caliper gauge, measure the bushing bore diameter of the cylinder head.
c. Select a new guide bushing (STD size or 0/S 0.05). If the bushing bore diameter of the cylinder head is greater than 11.027 mm (0.4341 in.), machine the bushing bore to the following dimension: 11.050 - 11.077 mm (0.4350 - 0.4361 in.)
If the bushing bore diameter of the cylinder head is greater than 11.077 mm (0.4361 in.), replace the cylinder head.
d. Using SST and a hammer, tap in a new guide bushing until there is 12.7 - 13.1 mm (0.500 - 0.516 in.) protruding from the cylinder head. SST 09201-70010
HINT: Different bushing are used for the intake and exhaust.
e. Using a sharp 6 mm reamer, ream the guide bushing to obtain the standard specified clearance between the guide bushing and valve stem.
7. 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: 0.8 - 1.2 mm (0.031 - 0.047 in.)
Minimum margin thickness: 0.5 mm (0.020 in.)
If the margin thickness is less than minimum, replace the valve.
d. Check the valve overall length.
Standard overall length:
Intake 93.45 mm (3.6791 in.)
Exhaust 93.89 mm (3.6965 in.)
Minimum overall length:
Intake 92.95 mm (3.6594 in.)
Exhaust 93.39 mm (3.6768 in.)
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 overall length.
8. Inspect and clean valve seats.
a. Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal 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 in.)
d. 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 seating is too low on the valve face, use 75°, 60° (IN only) 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.
9. Inspect valve springs.
a. Using a steel square, measure the squareness of the valve spring.
Maximum squareness: 2.0 mm (0.079 in.)
If squareness is greater than maximum, replace the valve spring.
b. Using a vernier caliper, measure the free length of the valve spring.
Free length: 39.8 mm (1.567 in.)
It 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: 148 - 164 N (15.1 - 16.7 kgf, 33.3 - 36.8 lbf) at 31.8 mm (1.252 in.)
If the installed tension is not as specified, replace the valve spring.
10. Inspect camshaft and bearings.
a. Inspect Camshaft runout
1. Place the camshaft on V-blocks.
2. Using a dial indicator, measure the circle runout at the center journal. Maximum circle runout: 0.04 mm (0.0016 in.)
If the circle runout is greater than maximum, replace the camshaft.
b. Inspect cam lobes
Using a micrometer, measure the cam lobe height.
Standard cam lobe height:
Intake 41.510 - 41.610 mm (1.6343 - 1.6382 in.)
Exhaust 41.310 - 41.410 mm (1.6264 - 1.6303 in.)
Minimum cam lobe height:
Intake 41.36 mm (1.6283 in.)
Exhaust 41.16 mm (1.6205 in.)
If the cam lobe height is greater than minimum, replace the camshaft.
c. Inspect camshaft journals
Using a micrometer, measure the journal diameter.
Journal diameter:
Exhaust No.1 24.949 - 24.965 mm (0.9822 - 0.9829 in.)
Others 22.949 - 22.965 mm (0.9035 - 0.9041 in.)
If the journal diameter is not as specified, check the oil clearance.
d. Inspect camshaft bearings for flaking and scoring. If the bearings are damaged, replace the bearing caps and cylinder head as a set.
e. Inspect camshaft gear spring
Using a vernier caliper, measure the free distance between the spring ends.
Free distance: 22.5 - 22.9 mm (0.886 - 0.902 in.)
If the free distance is not as specified, replace the gear spring.
f. Inspect camshaft journal oil clearance
1. Clean the bearing caps and camshaft journals.
2. Place the camshafts on the cylinder head.
3. lay a strip of Plastigage across each of the camshaft journals.
4. Install the bearing caps.
Torque: 13 N.m (130 kgf.cm, 9 ft.lbf)
NOTICE: Do not turn the camshaft.
5. Remove the bearing caps.
6. Measure the Plastigage at its widest point.
Standard oil clearance: 0.035 - 0.072 mm (0.0014 - 0.0028 in.)
Maximum oil clearance: 0.10 mm (0.0039 in.)
If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
7. Completely remove the Plastigage.
g. Inspect camshaft thrust clearance
1. Install the camshaft.
2 Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance: 0.045 - 0.100 mm (0.0018 - 0.0039 in.)
Maximum thrust clearance: 0.12 mm (0.0047 in.)
If the thrust clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
h. Inspect camshaft gear backlash
1. Install the camshafts without installing the intake cam sub-gear.
2. Using a dial indicator, measure the backlash.
Standard backlash: 0.020 - 0.200 mm (0.0008 - 0.0079 in.)
Maximum backlash: 0.30 mm (0.0118 in.)
If the backlash is greater than maximum, replace the camshafts.
11. Inspect valve lifters and lifter bores.
a. Using a micrometer, measure the lifter diameter.
Lifter diameter: 27.975 - 27.985 mm (1.1014 - 1.1018 in.)
b. Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Lifter bore diameter: 28.000 - 28.021 mm (1.1024-1.1032 in.)
c. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.015 - 0.046 mm (0.0005 - 0.0018 in.)
Maximum oil clearance: 0.10 mm (0.0039 in.)
If the oil clearance is greater than maximum, replace the lifter. If necessary, replace the cylinder head.
12. Inspect intake and exhaust manifolds.
Using precision straight edge and thickness gauge, measure the surface contacting the cylinder head for warpage.
Maximum warpage:
Intake 0.1 mm (0.039 in.)
Exhaust 0.2 mm (0.079 in.)
If warpage is greater than maximum, replace the manifold.
13. If necessary, replace spark plug tube gasket.
a. Using a screwdriver, pry out the gasket.
b. Using SST, tap in a new gasket until its surface is flush with the upper edge of the cylinder head cover. SST 09550-10012 (09552-10010, 09560-10010)
c. Apply a light coat of MP grease to the gasket lip.