Inspection

INSPECTION, CLEANING AND REPAIR OF CYLINDER HEAD COMPONENTS






1. CLEAN TOP OF PISTONS AND TOP OF CYLINDER HEAD
(a) Turn the crankshaft and bring each piston to top dead center. Using a gasket scraper, remove all the carbon from the piston tops.
(b) Using a gasket scraper, remove all gasket material from the top of the block.

WARNING: Protect your eyes when using high-pressure air.






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

CAUTION: Be careful not to scratch the surfaces.






3. CLEAN COMBUSTION CHAMBER
Using wire brush, remove all 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 brush and solvent, clean all the valve guide bushings.

NOTE: Be careful not to damage the valve guide bushing interior.






5. CLEAN CYLINDER HEAD
Using a soft brush and solvent, throughly clean the head.






6. INSPECT CYLINDER HEAD FOR FLATNESS
Using a precision straight edge and thickness gauge, measure the surface contacting the cylinder block and manifold 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.






7. INSPECT CYLINDER HEAD FOR CRACKS
Using a dye penetrant, check the combustion chamber intake manifold and exhaust ports, head surface and top of the head for cracks. If cracked, replace the head.






8. CLEAN VALVES
(a) Using a gasket scraper, chip any carbon from the valve.
(b) Using a wire brush, throughly clean the valve.

NOTE: Be careful not to damage the seat valve surface.






9. INSPECT VALVE STEM AND GUIDE BUSHINGS
(a) Using a caliper gauge, measure the inside diameter of the valve guide.
Guide inside diameter: 6.01-6.03 mm (0.2366 - 0.2374 in.)






(b) Using a micrometer, measure the diameter of the valve stem.






(c) Subtract the valve stem measurement from the valve guide measurement.






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






10. IF NECESSARY, REPLACE VALVE GUIDE BUSHINGS
(a) Using SST and hammer, drive out the valve guide bushing. SST 09201-70010






(b) Using a caliper gauge, measure the valve guide bore of the cylinder head.






(c) Select a new valve guide bushing.
If the valve guide bushing bore is more than 11.027 mm (0.4341 in.), machine the bore to the following dimensions.
Rebored valve guide bushing bore dimensions: 11.050 - 11.077 mm (0.4350 - 0.4361 in.)






(d) Using SST and a hammer, drive in a new valve guide to where there is 13.3 - 14.1 mm (0.5236 - 05551 in.) protruding from the cylinder. SST 09201-70010






(e) Using a sharp 6mm reamer, ream the valve guide to obtain the standard specified clearance between the valve guide and valve stem. See step 9.






11. INSPECT AND GRIND VALVES
(a) Grind the valve only enough to remove pits and carbon.
(b) Check that the valves are ground to the correct valve face angle.
Valve face angle: 44.5°






(c) Check the valve head margin thickness.
Standard margin thickness: 1.0 mm (0.039 in.)
Minimum margin thickness: 0.8 mm (0.031 in.)
If the valve head margin thickness is less than minimum, replace the valve.






(d) Check the valve overall length.






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, regrind it with grinder or replace the valve if necessary.

CAUTION: Do not grind off more than the minimum overall length. See step 11d.






12. INSPECT AND CLEAN VALVE SEATS
(a) Using a 45° cutter, resurface the valve seats.






(b) Check the valve seating position.
Apply a thin coat of prussian blue (or white lead) to the valve face. Install the valve. While applying light pressure to the valve, 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 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: 1.2 - 1.6 mm (0.047 - 0.063 in.)
If not, correct the valve seat as follows: if seating is too high on the valve face, use 30° and 45° cutters to correct the seat.






- If seating is too low on the valve face, use 75° (IN), 60°(EX) and 45° cutters to correct the seat.






(d) Hand-lap the valve and valve seat with an abrasive compound.






13. INSPECT VALVE SPRING
(a) Using a steel square, measure the squareness of the valve springs.
Maximum squareness: 2.0 mm (0.079 in.)
If squareness is greater than maximum, replace the valve spring.






(b) Using calipers, measure the free length of the valve spring.
Free length: 41.52 mm (1.6346 in.)
If the free length is not within specification, replace the valve spring.






(c) Using a spring tester, measure the tension of the valve spring at the specified installed length.
Installed tension: 15.91kg (35.1 lb, 156 N) at 35.16 mm (1.3842 in.). If the installed tension is not as specified, replace the valve spring.






14. INSPECT CAMSHAFT
(a) Place the camshaft on V-blocks and, 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) Using a micrometer, measure the cam lobe height.






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






(c) Using a micrometer, measure journal diameter.
Standard diameter: 26.979 - 26.995 mm (1.0622 - 1.0628 in.) If the journal diameter is less than specified, replace the camshaft.






15. INSPECT CAMSHAFT OIL CLEARANCE
(a) Clean the bearing caps and camshaft journal.
(b) Place the camshaft in the cylinder head.
(c) Lay a strip of Plastigage across each journal.






(d) Place the bearing caps with the top of the number on the cap pointing toward the front and numerical order from the front side.
(e) Torque the cap bolts gradually from the inside in the three passes.
Torque: 140kg-cm (10 ft-lb. 14 N.m).

NOTE: Do not turn the camshaft while the Plastigage is in place.






(f) Remove the caps and measure the Plastigage at its widest point.
Standard oil clearance: 0.037 - 0.073 mm (0.0015 - 0.0029 in.)
Maximum oil clearance: 0.10 mm (0.0039 in.) If clearance is greater than maximum, replace the cylinder head and/or camshaft.
(g) Clean out the pieces of Plastigage from the bearing caps and journals.






16. INSPECT ROCKER ARMS
Check the contact surface of the valve rocker arm and valve stem end and/or camshaft lobe. If the contact surface of the valve stem end and/or camshaft lobe is worn excessively, replace the rocker arm.






17. INSPECT INTAKE AND EXHAUST MANIFOLD
Using a precision straight edge and thickness gauge, check the surface contacting the cylinder head for warpage.
Maximum warpage:
Intake manifold 0.20 mm (0.0079 in.)
Exhaust manifold 0.30 mm (0.0118 in.)