Inspection

DISASSEMBLY OF CYLINDER HEAD
1. REMOVE VALVE LIFTERS AND SHIMS

NOTE: 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.

NOTE: Arrange the valves, valve springs, spring seats and spring retainers in correct order.

(c) Using needle-nose pliers, remove the oil seal.
INSPECTION, CLEANING AND REPAIR OF CYLINDER HEAD COMPONENTS
1. CLEAN TOP OF PISTONS AND TOP OF 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.
(b) Remove all the gasket material from the top of the cylinder block.
(c) Using compressed air, blow carbon and oil from the bolt holes.

WARNING: Protect your eyes when using high pressure air.

2. REMOVE GASKET MATERIAL
Using a gasket scraper, remove all the gasket material from the manifold and cylinder head surface.

CAUTION: Be careful not to scratch the surfaces.

3. CLEAN COMBUSTION CHAMBERS

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

CAUTION: Be careful not to scratch the head gasket contact surface.

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 CYLINDER HEAD FOR FLATNESS

Using a precision straight edge and feeler gauge, measure the surfaces contacting the cylinder block and man for warpage.
Maximum warpage:
Cylinder block side 0.05 mm (0.0020 in.)
manifold side 0.08 mm (0.0031 in.)
If warpage is greater than maximum, replace the cylinder head.
7. INSPECT CYLINDER HEAD FOR CRACKS

Using a dye penetrant, check the combustion chamber, intake and exhaust ports, head surface and the top of the head for cracks. If cracked, replace the cylinder head.
8. CLEAN VALVES

(a) Use a gasket scraper, chip 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: 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 oil clearance is greater than maximum, replace the valve and guide bushing.
10. IF NECESSARY, REPLACE VALVE GUIDE BUSHINGS

(a) Insert an old valve wrapped with tape into the guide bushing and break off the guide bushing by hitting it with a hammer.

CAUTION: Be careful not to damage the lifter hole.

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

(d) Using a caliper gauge, measure the bushing bore diameter of the cylinder head.

(e) 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: Rebored cylinder head bushing bore 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.
(f) Gradually heat the cylinder head to 80 - 100°C (176 - 212°C).

(g) Using SST and a hammer, tap in a new guide bushing until the snap ring makes contact with the cylinder head. 551 09201-70010

(h) Using a sharp 6 mm reamer, ream the guide bushing to obtain the specified clearance between the guide bushing and the valve stem.
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 (000.39 in.)

11. INSPECT AND GRIND VALVES
(a) Grind the valve only 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 100.60 mm (3.9606 in.) Exhaust 100.45 mm (3.9547 in.)
Minimum overall length:
Intake 100.1 mm (3.941 in.)
Exhaust 100.0 mm (3.937 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.

CAUTION: Do not grind off more than the minimum overall length.

12. 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 thin coat of Prussian blue (or white lead) to the valve face. While applying light pressure to the valve, rotate the valve against the seat.
(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 seat are concentric. If not, resurface the seat.
- Check that the seat contact is on the middle of the valve face with the following width: 1.0 - 1.4 mm (0.039 - 0.055 in.) 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 75° 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.
13. INSPECT VALVE SPRINGS

(a) Using a steel square, measure the squareness of the valve spring.
Maximum squareness: 2.0 mm (0.075 in.)
If squareness is greater than maximum, replace the valve spring.

(b) Using calipers, measure the free length of the valve spring.
Free length: 45.0 mm (1.772 in.)
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: 16.7 - 19.3 kg (36.8 - 42.5 lb, 164 -189 N) at 34.7 mm (0.000 in.)
If the installed tension is not as specified, replace the valve spring.

14. INSPECT CAMSHAFTS AND BEARINGS
A. 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: 0.04 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: 34.910 - 35.010 mm (1.3744 - 1.3783in.)
Exhaust: 35.560 - 35.660 mm (1.4000 - 1.4039 in.)
Minimum cam lobe height
Intake: 34.80 mm (1.3701 in.)
Exhaust: 35.45 mm (1.3957 in.)
If the cam lobe height is less than minimum, replace the camshaft.

C. Inspect camshaft journals
Using a micrometer, measure the journal diameter.
Standard diameter: 26.959 - 26.975 mm (1.0614 - 1.0620 in.)
If the journal diameter is not as specified, check the oil clearance.
D. Inspect camshaft bearings
check the 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 calipers, measure the free distance between the spring end.
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
(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. (See step 4 on pages EM-68 and 69)
Torque: 190kg-cm (14 ft-lb, 19 N.m)

NOTE: Do not turn the camshaft.

(e) Remove the bearing caps.
(f) Measure the Plastigage at its widest point.
Standard oil clearance: 0.025 - 0.062 mm (0.0010-0.0024 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.
(g) Completely remove the Plastigage.

G. Inspect camshaft thrust clearance
(a) Install the camshafts.
NOTE: Since the thrust clearance of the camshaft is small, the camshaft must be held level while it is being installed. If the camshaft is not kept level, the portion of the cylinder head receiving the shaft thrust may crack or be damaged, causing the camshaft to seize or break. To avoid this damage, the following steps should be carried out.
(b) Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance:
Intake: 0.045 - 0.100 mm (0.0018 - 0.0039 in.)
Exhaust: 0.030 - 0.085 mm (0.0012 - 0.0033 in.)
Maximum thrust clearance:
Intake: 0.12 mm (0.0047 in.)
Exhaust: 0.10 mm (0.0039 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
(a) Install the camshafts without installing the exhaust cam sub-gear. (See step 4 on page EM-67 to 69)
(b) Using a dial indicator, measure the backlash.
Standard backlash: 0.020 - 0.200 mm (0.0008 - 0.0079 in.)
Maximum backlash: 0.30 mm (0.0188 in.)
If the backlash is greater than maximum, replace the camshafts.

15. 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: 0.07 mm (0.0028 in.)
If the oil clearance is greater than maximum, replace the lifter. If necessary, replace the cylinder head.

16. INSPECT INTAKE AND EXHAUST MANIFOLDS
Using a precision straight edge and feeler gauge, measure the surface contacting the cylinder head for warpage.
Maximum warpage: 0.30 mm (0.0118 in.) If warpage is greater than maximum, replace the manifold.