Clean the cylinder head.

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

• ПРИМЕЧАНИЕ:

• Do not scratch the surface that contacts the cylinder block.

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

Using a soft brush and solvent, thoroughly clean the cylinder head.

Inspect the cylinder head warpage.

Inspect the cylinder head for cracks.

Using a gasket scraper, chip off any carbon from the valve head.

Using a wire brush, thoroughly clean the valve.

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

• Standard valve stem diameter:
• 7.975 to 7.990 mm (0.3140 to 0.3146 in.)

If the diameter is not as specified, replace the intake valve.

Check the valve face angle.

Check the head margin thickness.

• Standard margin thickness:
• 1.6 mm (0.0630 in.)

• Minimum margin thickness:
• 1.1 mm (0.0433 in.)

If the margin thickness is less than the minimum, replace the intake valve.

Check the overall length of the valve.

• Standard overall length:
• 104.10 to 104.50 mm (4.10 to 4.11 in.)

• Minimum overall length:
• 103.60 mm (4.08 in.)

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

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 intake valve.

• ПРИМЕЧАНИЕ:

• Do not grind the valve so it becomes shorter than the minimum overall length.

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

• Standard valve stem diameter:
• 7.960 to 7.975 mm (0.3134 to 0.3140 in.)

If the diameter is not as specified, replace the exhaust valve.

Check the valve face angle.

Check the valve head margin thickness.

• Standard margin thickness:
• 1.7 mm (0.0669 in.)

• Minimum margin thickness:
• 1.2 mm (0.0472 in.)

If the margin thickness is less than the minimum, replace the exhaust valve.

Check the overall length of the valve.

• Standard overall length:
• 103.95 to 104.35 mm (4.09 to 4.11 in.)

• Minimum overall length:
• 103.45 mm (4.07 in.)

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

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 exhaust valve.

• ПРИМЕЧАНИЕ:

• Do not grind the valve so it becomes shorter than the minimum overall length.

Using a steel square, measure the deviation of the spring.

• Maximum deviation:
• 2.0 mm (0.0787 in.)

If the deviation is more than the maximum, replace the spring.

Using a vernier caliper, measure the free length of the spring.

• Standard Free Length:
• 46.20 mm (1.82 in.)

If the free length is not as specified, replace the spring.

Using a spring tester, measure the tension of the valve spring at the installed length.

• Standard tension:
• 301 to 332 N (31 to 34 kgf, 66.6 to 74.6 lbf) at 37.00 mm (1.46 in.)

If the tension is not as specified, replace the spring.

Using a caliper gauge, measure the inside diameter of the guide bush.

• Standard bush inside diameter:
• 8.010 to 8.030 mm (0.315 to 0.316 in.)

Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.

• Standard oil clearance:
• 0.020 to 0.055 mm (0.000787 to 0.00217 in.)

• Maximum oil clearance:
• 0.08 mm (0.00315 in.)

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

Using a caliper gauge, measure the inside diameter of the guide bush.

• Standard bush inside diameter:
• 8.010 to 8.030 mm (0.315 to 0.316 in.)

Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.

• Standard oil clearance:
• 0.035 to 0.070 mm (0.00138 to 0.00276 in.)

• Maximum oil clearance:
• 0.10 mm (0.00394 in.)

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

Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats.

Check the valve seating position.

Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats.

Check the valve seating position.

Using a micrometer, measure the lifter diameter.

• Standard lifter diameter:
• 40.892 to 40.902 mm (1.6099 to 1.6103 in.)

Using a caliper gauge, measure the lifter bore diameter of the cylinder head.

• Standard lifter bore diameter:
• 40.960 to 40.980 mm (1.6126 to 1.6134 in.)

Subtract the lifter diameter measurement from the lifter bore diameter measurement.

• Standard oil clearance:
• 0.058 to 0.088 mm (0.00238 to 0.00346 in.)

• Maximum oil clearance:
• 0.10 mm (0.00394 in.)

If the oil clearance is more than the maximum, replace the lifter. If necessary, replace the cylinder head.

Inspect the journal diameter of the camshaft.

Check the oil clearance.

Clean the bearing caps and journals.

Check the bearings for flaking and scoring.

If the bearings are damaged, replace the bearing caps and cylinder head as a set.

Install the bearings to the bearing caps and cylinder head.

Place the camshaft on the cylinder head.

Lay a strip of Plastigage across each of the journals.

Text in Illustration

*1	Plastigage

Install the bearing caps (See page ).

• ПРИМЕЧАНИЕ:

• Do not turn the camshaft.

Remove the bearing caps (See page ).

Measure the Plastigage at its widest point.

• Standard oil clearance:
• 0.022 to 0.074 mm (0.000866 to 0.00291 in.)

• Maximum oil clearance:
• 0.10 mm (0.00394 in.)

Text in Illustration

*1	Plastigage

If the oil clearance is more than the maximum, replace the cylinder head sub-assembly. If necessary, grind or replace the camshaft.

Completely remove the Plastigage.

Remove the camshaft.

Check the thrust clearance.

Install the camshaft.

Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.

• Standard thrust clearance:
• 0.080 to 0.280 mm (0.00351 to 0.0110 in.)

• Maximum thrust clearance:
• 0.35 mm (0.0138 in.)

If the thrust clearance is more than the maximum, replace the No. 1 bearing. If necessary, replace the camshaft.