Inspection

CYLINDER HEAD

INSPECTION





1. INSPECT CYLINDER HEAD FOR FLATNESS
a) Using a precision straightedge and feeler gauge, measure the surface that is in contact with the cylinder block and the manifolds for warpage.

Maximum warpage:

Maximum warpage

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





2. 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.





3. INSPECT CYLINDER HEAD SET BOLT
a) Using a vernier caliper, measure the length of head bolts from the seat to the end.
Standard length: 142.8 to 144.2 mm (5.622 to 5.677 inch)
Maximum length: 147.1 mm (5.791 inch)
If the length is greater than the maximum, replace the bolt.





4. INSPECT CYLINDER BLOCK FOR FLATNESS
a) Using a precision straightedge and feeler gauge, measure the surface which is in contact with the cylinder head gasket for warpage.
Maximum warpage: 0.05 mm (0.0020 inch)
If the warpage is greater than the maximum, replace the cylinder block.





5. INSPECT INTAKE VALVE
a) Check the overall valve length.
Standard overall length: 89.25 mm (3.5138 inch)
Minimum overall length: 88.75 mm (3.4941 inch)
If the overall length is less than the minimum, replace the valve.





b) Using a micrometer, measure the diameter of the valve stem.
Standard valve stem diameter: 4.970 to 4.985 mm (0.1957 to 0.1963 inch)





c) Check the valve head margin thickness.
Standard margin thickness: 1.0 mm (0.039 inch)
Minimum margin thickness: 0.7 mm (0.028 inch)
If the margin thickness is less than the minimum, replace the valve.

6. INSPECT EXHAUST VALVE
a) Check the overall valve length.
Standard overall length: 87.90 mm (3.4606 inch)
Minimum overall length: 87.40 mm (3.4409 inch)
If the overall length is less than the minimum, replace the valve.
b) Using a micrometer, measure the diameter of the valve stem.
Standard valve stem diameter: 4.965 to 4.980 mm (0.1955 to 0.1961 inch)
c) Check the valve head margin thickness.
Standard margin thickness: 1.15 mm (0.045 inch)
Minimum margin thickness: 0.7 mm (0.028 inch)
If the margin thickness is less than the minimum, replace the valve.





7. INSPECT VALVE SPRING
a) Using a vernier caliper, measure the free length of the valve spring.
Standard free length: 45.05 to 45.15 mm (1.774 to 1.778 inch)
If the free length is not as specified, replace the spring.





b) Using a steel square, measure the deviation of the valve spring.
Maximum deviation: 1.6 mm (0.063 inch)
Maximum angle (reference): 2°
If the deviation is greater than the maximum, replace the spring.





c) Using a spring tester, measure the tension of the valve spring at the specified installed length.
Standard installed tension: 149 to 165 N (15.2 to 16.8 kgs, 33.5 to 37.1 lbs.) at 32.5 mm (1.280 inch)
Maximum working tension: 286 to 316 N (29.1 to 32.2 kgs, 64.2 to 71.0 lbs.) at 23.9 mm (0.941 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: 5.010 to 5.030 mm (0.1972 to 0.1980 inch)
b) Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.

Standard oil clearance

Standard oil clearance:

Maximum oil clearance

Maximum oil clearance:

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

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





c) Check the valve face and seat according to this procedure.
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 the width between 1.0 to 1.4 mm (0.039 to 0.055 inch).





10. REPAIR INTAKE VALVE SEAT
a) If the seating is too high on the valve face, use 20° and 45° cutters to correct the seat.





b) If the seating is too low on the valve face, use 75° and 45° cutters to correct the seat.
c) Hand-lap the valve and valve seat with an abrasive compound.
d) Recheck the valve seating position.





11. REPAIR EXHAUST VALVE SEAT
a) If the seating is too high on the valve face, use 20° and 45° cutters to correct the seat.





b) If the seating is too low on the valve face, use 75° and 45° cutters to correct the seat.
c) Hand-lap the valve and valve seat with an abrasive compound.
d) Recheck the valve seating position.





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





13. INSPECT VALVE LIFTER OIL CLEARANCE
a) Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Standard lifter bore diameter: 31.000 to 31.025 mm (1.2205 to 1.2215 inch)
b) Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.024 to 0.059 mm (0.0009 to 0.0023 inch)
Maximum oil clearance: 0.1 mm (0.0039 inch)
If the oil clearance is greater than the maximum, replace the lifter. If necessary, replace the cylinder head.

14. INSPECT CAMSHAFT TIMING GEAR OPERATION
a) Check the lock of the camshaft timing gear.
1) Clamp the camshaft in a vise, and check that the camshaft timing gear is locked.

NOTICE: Be careful not to damage the camshaft.





b) Release the lock pin.
1) Cover the 4 oil paths of the cam journal with tape as shown in the illustration.

HINT: One of the 2 grooves located on the cam journal is for retarding cam timing (upper) and the other is for advancing cam timing (lower). Each groove has 2 oil paths. Plug one of the oil paths for each groove with rubber pieces before wrapping the cam journal with the tape.

2) Puncture the tape for the advance oil path and for the retard oil path on the opposite side from the advance oil path.





3) Apply air pressure into the 2 broken tape paths (the advance side path and retard side path) with about 150 kPa (1.5 kgf/cm2, 22 psi).

NOTICE: Cover the paths with cloth or equivalent to prevent oil from splashing.





4) Confirm if the camshaft timing gear assembly revolves in the timing advance direction when reducing the air pressure of the timing retard path.

HINT: The lock pin is released, and the camshaft timing gear revolves in the advance direction.

5) When the camshaft timing gear reaches the most advanced position, remove the air pressure of the timing retard side path, and then release the air pressure of the timing advance side path.

NOTICE: The camshaft timing gear assembly occasionally shifts to the retard side abruptly if the air compression of the advanced side path is released first. This often results in the breakage of the lock pin.

c) Check smooth revolution.
1) Except the position where the lock pin meets at the most retarded angle, let the valve timing controller assembly turn back and forth. Check the movable range and that there is no disturbance.
Standard condition: Smooth movable range is about 22.5°

NOTICE: Be sure to perform this check by hand, instead of air pressure.

d) Check the lock in the most retarded position.
1) Confirm that the camshaft timing gear assembly is locked at the most retarded position.





15. INSPECT CAMSHAFT TIMING GEAR
a) Wrap the chain around the timing sprocket.
b) Using a vernier caliper, measure the diameter of the timing gear with the chain.
Minimum gear diameter (w/chain): 96.2 mm (3.787 inch)
If the diameter is less than the minimum, replace the sprocket.

NOTICE: Vernier caliper must come into contact with the chain link for measuring.





16. INSPECT CAMSHAFT TIMING SPROCKET
a) Wrap the chain around the timing sprocket.
b) Using a vernier caliper, measure the diameter of the timing gear with the chain.
Minimum gear diameter (w/chain): 96.2 mm (3.787 inch)
If the diameter is less than the minimum, replace the sprocket.

NOTICE: Vernier caliper must come into contact with the chain link for measuring.





17. INSPECT CAMSHAFT
a) Inspect the camshaft for runout.
1) Place the camshaft on V-blocks.
2) Using a dial indicator, measure the circle runout at the center journal.
Maximum circle runout: 0.03 mm (0.0012 inch)
If the circle runout is greater than the maximum, replace the camshaft.





b) Inspect the cam lobes.
1) Using a micrometer, measure the cam lobe height.
Standard cam lobe height: 44.617 to 44.717 mm (1.7566 to 1.7605 inch)
Minimum cam lobe height: 44.47 mm (1.7508 inch)
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.

Standard journal diameter

Standard journal diameter:

If the journal diameter is not as specified, check the oil clearance.

18. INSPECT NO. 2 CAMSHAFT
a) Inspect the camshaft for runout.
1) Place the camshaft on V-blocks.
2) Using a dial indicator, measure the circle runout at the center journal.
Maximum circle runout: 0.03 mm (0.0012 inch)
If the circle runout is greater than the maximum, replace the camshaft.
b) Inspect the cam lobes.
1) Using a micrometer, measure the cam lobe height.
Standard cam lobe height: 44.666 to 44.766 (1.7585 to 1.7624 inch)
Minimum cam lobe height: 44.52 mm (1.7528 inch)
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.

Standard journal diameter:

If the journal diameter is not as specified, check the oil clearance.





19. 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 0.095 mm (0.0016 to 0.0037 inch)
Maximum thrust clearance: 0.11 mm (0.0043 inch)
If the thrust clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and the cylinder head together.

20. INSPECT CAMSHAFT OIL CLEARANCE
a) Clean the bearing caps and the 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.
Torque: 23 Nm (235 kgf-cm, 17 ft. lbs.) for No. 1
13 Nm (129 kgf-cm, 9 ft. lbs.) for No. 2

NOTICE: Do not turn the camshaft.

e) Remove the bearing caps.





f) Measure the Plastigage at its widest point.
Standard oil clearance: 0.040 to 0.095 mm (0.0016 to 0.0037 inch)
Maximum oil clearance: 0.115 mm (0.0045 inch)
If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the bearing caps and the cylinder head together.

NOTICE: Completely remove the Plastigage.