Cylinder Head Assembly: Testing and Inspection

CYLINDER HEAD

INSPECTION

1. INSPECT CYLINDER HEAD SET BOLT
a. Using a vernier caliper, measure the tension portion diameter of the bolt.
Standard outside diameter: 8.95 to 9.05 mm (0.3524 to 0.3563 inch)
Minimum outside diameter: 8.75 mm (0.3445 inch)
If the diameter is less than the minimum, replace the bolt.

2. INSPECT CAMSHAFT
a. Inspect the camshaft for runout.
(1) Place the camshaft on V-blocks.
(2) Using a dial indicator, measure the runout at the center journal.
Maximum circle runout: 0.06 mm (0.0024 inch)
If the runout is greater the maximum, replace the camshaft.

b. Inspect the cam lobes.
(1) Using a micrometer, measure the cam lobe height.

Standard Cam Lobe Height:

Minimum Cam Lobe Height:

If the cam lobe height is less than the minimum, replace the camshaft.

c. Inspect the camshaft journals.
(1) Using a micrometer, measure the journal diameter.
Journal diameter: 26.959 to 26.975 mm (1.0614 to 1.0620 inch)
If the journal diameter is not as specified, check the oil clearance.

3. INSPECT CYLINDER HEAD FOR FLATNESS
a. Using a precision straight edge and a feeler gauge, measure the surface contacting the cylinder block and the manifolds for warpage.

Maximum Warpage:

If the warpage is greater than the maximum, replace the cylinder head.

4. INSPECT CYLINDER HEAD FOR CRACKS
a. Using a dye penetrant, check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks. If cracked, replace the cylinder head.

5. INSPECT INTAKE VALVE
a. Check the valve overall length.
Standard overall length: 95.45 mm (3.7579 inch)
Minimum overall length: 94.95 mm (3.7382 inch)
If the overall length is less than the minimum, replace the valve.

b. Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter: 5.470 to 5.485 mm (0.2154 to 0.2159 inch)
If the diameter is less than the minimum, replace the intake valve.

c. 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 the minimum, replace the valve.

6. INSPECT EXHAUST VALVE
a. Check the valve overall length.
Standard overall length: 95.40 mm (3.7559 inch)
Minimum overall length: 94.90 mm (3.7362 inch)
If the overall length is less than the minimum, replace the valve.

b. Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter: 5.465 to 5.480 mm (0.2152 to 0.2157 inch)
If the diameter is less than the minimum, replace the exhaust valve.

7. INSPECT INNER COMPRESSION SPRING
a. Using a vernier caliper, measure the free length of the valve spring.
Free length: 45.50 mm (1.7913 inch)
If the free length is not as specified, replace the valve spring.

b. Using steel squares, 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.

c. Using a spring tester, measure the tension of the valve spring at the specified installed length.
Installed tension: 186 to 206 N (19.0 to 21.0 kgf, 41.9 to 46.3 ft. lbs.) at 33.8 mm (1.331 inch)
If the installed tension is not as specified, replace the valve spring.

8. INSPECT VALVE GUIDE BUSH OIL CLEARANCE
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.

Maximum Oil Clearance:

If the clearance is greater than the maximum, replace the valve and guide bush.

Standard Oil Clearance:

9. REMOVE VALVE GUIDE BUSH
a. Heat the cylinder head to approximately 80 to 100°C (176 to 212°F).

b. Using SST and a hammer, tap out the guide bush.
SST 09201-10000, 09201-01055, 09950-70010 (09951-07100)

10. INSTALL VALVE GUIDE BUSH
a. Using a caliper gauge, measure the bush bore diameter of the cylinder head.
Diameter: 10.295 to 10.313 mm (0.4053 to 0.4060 inch)
If the bush bore diameter of the cylinder head is greater than 10.313 mm (0.4060 inch), machine the bush bore to the dimension of 10.345 to 10.363 mm (0.4073 to 0.4080 inch).

Bush Diameter:

b. Using vernier caliper, measure the new valve guide bush length.

HINT: Use different bushes on the intake and exhaust.

Bush Length:

c. Heat the cylinder head to approximately 80 to 100°C (176 to 2120°)
d. Using SST and a hammer, tap in a new guide bush to the specified protrusion height.
SST 09201-10000, 09201-01055, 09950-70010 (09951-07100)

Protrusion Height:

e. Using a sharp 5.5mm reamer, ream the guide bush to obtain the standard specified clearance between the guide bush and the valve stem.

Standard Oil Clearance:

11. INSPECT VALVE SEATS
a. Apply a light coat of Prussian blue (or white lead) to the valve face.
b. Lightly press the valve against the seat.

NOTICE: Do not rotate the valve.

c. Check the valve face and valve seat according to this procedure.
(1) If blue appears 360° around the valve face, the valve face is concentric. If not, replace the valve.
(2) If blue appears 360° around the valve seat, the guide and valve face are concentric. If not, resurface the valve seat.
(3) Check that the valve seat contact is in the middle of the valve face with the width between 1.0 to 1.4 mm (0.039 to 0.055 inch).
12. REPAIR VALVE SEATS

NOTICE: Releasing the seat-cutter pressure gradually helps to make smoother valve seat faces.

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. Recheck the valve seating position.

13. INSPECT VALVE LIFTER
a. Using a micrometer, measure the lifter diameter.
Lifter diameter: 30.966 to 30.976 mm (1.2191 to 1.2195 inch)

14. INSPECT VALVE LIFTER OIL CLEARANCE
a. Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Lifter bore diameter: 31.009 to 31.025 mm (1.2208 to 1.2215 inch)
b. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.033 to 0.059 mm (0.0013 to 0.0023 inch)
Maximum oil clearance: 0.070 mm (0.0028 inch)
If the oil clearance is greater than the maximum, replace the lifter. If necessary, replace the cylinder head.
15. INSPECT CAMSHAFT GEAR BACKLASH
a. Install the camshaft timing gear assembly.
b. Install the camshafts to the cylinder head.

NOTICE:
^ Install without valves and sub gear.
^ Install with its timing mark matched.

c. Set the dial indicator to the teeth of the intake camshaft at a right angle (90°).
d. Measure the backlash of the camshaft timing gear at least 4 positions.
Standard backlash: 0.020 to 0.200 mm (0.0008 to 0.0079 inch)
Maximum backlash: 0.300 mm (0.0118 inch)
If the backlash is greater than the maximum, replace the camshafts.

16. INSPECT CAMSHAFT THRUST CLEARANCE
a. Install the camshafts.
b. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance: 0.040 to 0.090 mm (0.0016 to 0.035 inch)
Maximum thrust clearance: 0.120 mm (0.0047 inch)
If the thrust clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head together.
17. INSPECT CAMSHAFT 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 journal.
d. Install the bearing caps.
Torque: 16 Nm (163 kgf-cm, 12 ft. lbs.)

NOTICE: Do not turn the camshaft.

e. Remove the bearing caps.

f. Measure the Plastigage at its widest point.
Standard oil clearance:
Intake #4, #5 journals: 0.025 to 0.057 mm (0.0010 to 0.0022 inch)
Other journals: 0.025 to 0.062 mm (0.0010 to 0.0024 inch)
Maximum oil clearance: 0.100 mm (0.0039 inch)
If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head together.

NOTICE: Completely remove the Plastigage.