Cylinder Head

OVERHAUL





1. REMOVE VALVE LIFTER

HINT: Arrange the valve lifter in the correct order.





2. REMOVE VALVE

HINT: Arrange the valves, inner compression springs, valve spring retainers and valve spring retainer locks in the correct order.

a. Place the cylinder head on a wooden block.
b. Using SST, compress the inner compression spring and remove the 2 valve spring retainer locks.
SST 09202-70020 (09202-00010)
c. Remove the valve, inner compression spring, valve spring and valve spring retainer.





3. REMOVE VALVE SPRING SEAT
a. Using compressed air and a magnetic finger, remove the valve spring seat by blowing air.





4. REMOVE VALVE STEM OIL O SEAL OR RING
a. Using needle-nose pliers, remove the valve stem oil seal.
5. CLEAN CYLINDER HEAD SUB-ASSEMBLY





a. 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.





b. Using a wire brush, remove all the carbon from the combustion chambers.

NOTICE: Be careful not to scratch the combustion chambers.





c. Using a valve guide bushing brush and solvent, clean all the valve guide bushes.





d. Using a soft brush and solvent, thoroughly clean the cylinder head.
6. INSPECT CYLINDER HEAD SUB-ASSEMBLY





a. Inspect warpage.
1 Using a precision straight edge and feeler gauge, measure the warpage of the contact surfaces of the cylinder block and manifolds.
Maximum warpage: 0.10 mm (0.0039 inch)
If warpage is greater than the maximum, replace the cylinder head.





b. Inspect cranks.
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.





7. CLEAN VALVE
a. Using a gasket scraper, chip off any carbon from the valve head.
b. Using a wire brush, thoroughly clean the valve.
8. INSPECT VALVE





a. Inspect the valve stem diameter.
1 Using a micrometer, measure the diameter of the valve stem.





Valve stem diameter





b. Inspect 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°





c. Inspect the valve head margin thickness.
1 Using vernier calipers, 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.





d. Inspect the overall length.
1 Using vernier calipers, check the overall length.





Standard overall length





Minimum overall length

If the overall length is less than the minimum, replace the valve.





e. Inspect the valve stem tip.
1 Check the surface of the valve stem tip for wear.

NOTICE: Do not grind off more than the minimum length.

If the valve stem tip is worn, resurface the tip with a grinder or replace the valve.





9. CLEAN VALVE SEAT
a. Using a 45° carbide cutter, resurface the valve seats.
b. Clean the valve seats.





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

NOTICE: Do not rotate the valve.

c. Check the valve face and seat according to the following procedure.
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 valve seat.
3 Check that the seat contacts the middle of the valve face with the width below.
Standard width: 1.0 to 1.4 mm (0.039 to 0.055 inch)
11. REPAIR VALVE SEAT

NOTICE: Take off a cutter gradually to make the intake valve seat smooth.





a. If the seating is too high to the valve face, use 30° and 45° cutters to correct the seat.





b. Intake side:
If the seating is too low to the valve face, use 60° and 45° cutters to correct the seat.





c. Exhaust side:
If the seating is too low to the valve face, use 75° and 45° cutters to correct the seat.





d. Hand rub the valve and valve seat with an abrasive compound.
e. After hand-rubbing, clean the valve and valve seat.
12. INSPECT INNER COMPRESSION SPRING





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





b. Inspect free length.
1 Using vernier calipers, measure the free length of the inner compression spring.
Free length: 47.80 mm (1.8819 inch)
If the free length is not as specified, replace the inner compression spring.





c. Inspect tension.
1 Using a spring tester, measure the tension of the inner compression spring at the specified installed length.
Installed tension: 186.2 to 205.8 N (19.0 to 21.0 kgf, 41.9 to 46.3 ft. lbs.) at 33.3 mm (1.311 inch)
If the installed tension is not as specified, replace the inner compression spring.





13. INSPECT VALVE GUIDE BUSH OIL CLEARANCE
a. Using a caliper gauge, measure the inside diameter of the valve guide bush.
Inside diameter: 5.51 to 5.53 mm (0.2169 to 0.2177 inch)
b. Subtract the valve stem diameter measurement (Step 8) from the valve guide bush inside diameter measurement.





Standard oil clearance





Maximum oil clearance

If the oil clearance is greater than the maximum, replace the valve and valve guide bush.
14. REMOVE VALVE GUIDE BUSH





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





b. Place the cylinder head on a wooden block.
c. Using SST, tap out the valve guide bush.
SST 09201-10000, 09201-01055, 09950-70010 (09951-07100)
15. INSTALL VALVE GUIDE BUSH





a. Using a caliper gauge, measure the bush bore diameter of the cylinder head.
Bush bore diameter: 10.295 to 10.315 mm (0.4053 to 0.4061 inch)
If the bush bore diameter of the cylinder head is greater than 10.315 mm (0.4061 inch), machine the bush bore to the dimension of 10.345 to 10.365 mm (0.4073 to 0.4081 inch).





Valve guide bush diameter





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





c. Place the cylinder head on a wooden block.
d. Using SST, tap in a new valve guide bush to the specified protrusion height.
SST 09201-10000, 09201-01055, 09950-70010 (09951-07100)
Protrusion height: 9.3 to 9.7 mm (0.366 to 0.382 inch)





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





Standard oil clearance





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





17. 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 valve lifter diameter measurement (Step 16) from the lifter bore diameter measurement.
Standard oil clearance: 0.033 to 0.059 mm (0.0013 to 0.0023 inch)
Maximum oil clearance: 0.08 mm (0.0031 inch)
If the oil clearance is greater than the maximum, replace the valve lifter.
If necessary, replace the cylinder head.
18. INSPECT CAMSHAFT OIL CLEARANCE





a. Clean the camshaft bearing caps, camshaft bearings and camshaft journals.
b. Install the camshaft bearing.
c. Place the camshaft on the cylinder head.
d. Lay a strip of Plastigage across each of the camshaft journals.
e. Install the camshaft bearing caps.

NOTICE: Do not turn the camshafts.

f. Remove the camshaft bearing caps.





g. Measure the Plastigage at its widest point.





Standard oil clearance (Cylinder head RH)





Standard oil clearance (Cylinder head LH)





Maximum oil clearance (Cylinder head RH)

Maximum oil clearance (Cylinder head LH): 0.10 mm (0.0039 inch)
If the oil clearance is greater than the maximum, replace the camshaft bearings and/or camshaft. If necessary, replace the camshaft bearing caps and cylinder head together.





Reference

h. Remove the Plastigage completely.
i. Remove the camshafts.
j. Remove the camshaft bearing.





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: 0.04 to 0.09 mm (0.0016 to 0.0035 inch)
Maximum thrust clearance: 0.11 mm (0.0043 inch)
If the thrust clearance is greater than the maximum, replace the camshafts.
If necessary, replace the camshaft bearing caps and cylinder head as a set.





20. INSTALL RING PIN
a. Using a plastic-faced hammer, tap in new ring pins until it reaches the specified protrusion height.
Specified protrusion height: 2.7 to 3.3 mm (0.106 to 0.130 inch)





21. INSTALL STRAIGHT PIN
a. Using a plastic-faced hammer, tap in new straight pins until it reaches the specified protrusion height.





Specified protrusion height





22. INSTALL STUD BOLT
a. Using the Torx(R) socket wrench E5 and E7, install the stud bolts.
Torque:
9.0 Nm (92 kgf-cm, 80 inch lbs.) for stud bolt A
4.0 Nm (41 kgf-cm, 35 inch lbs.) for stud bolt B
20 Nm (199 kgf-cm, 14 ft. lbs.) for stud bolt C
23. INSTALL UNION





a. Apply adhesive to 2 or 3 threads of the bolt end.
Adhesive: Part No. 08833-00070, THREE BOND 1324 or equivalent





b. Using a deep socket wrench 12, install the unions.
Torque: 15 Nm (150 kgf-cm, 11 ft. lbs.)
24. INSTALL TIGHT PLUG





a. Apply adhesive around the tight plug.





b. Using SST, tap in the tight plugs to the specified depth.
SST 09950-60010 (09951-00250), 09950-70010 (09951-07150)
Specified depth: 1.5 mm (0.059 inch)





25. INSTALL W/ HEAD STRAIGHT SCREW PLUG
a. Using a straight hexagon wrench 14, install a new gasket and straight screw plug.
Torque: 80 Nm (816 kgf-cm, 59 ft. lbs.)
26. INSTALL VALVE STEM OIL O SEAL OR RING

HINT: The intake valve stem oil seal is light brown and the exhaust valve stem oil seal is gray.





a. Apply a light coat of engine oil to the valve guide bush.





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





27. INSTALL VALVE SPRING SEAT
28. INSTALL VALVE





a. Apply engine oil to the valve as shown in the illustration.





b. Place the cylinder head on a wooden block.
c. Install the valve, inner compression spring and valve spring retainer.
d. Using SST, compress the inner compression spring and place the 2 valve spring retainer locks around the valve stem.
SST 09202-70020 (09202-00010)





e. Using a pin punch 5, lightly tap the valve stem tip to ensure a proper fit.

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





29. INSTALL VALVE LIFTER
a. Apply engine oil to the valve stem end and valve lifter, and install the valve lifter to the valve stem.
b. Check that the valve lifter rotates smoothly by hand.