Valve Clearance: Service and Repair
CAMSHAFT
Valve Clearance
CHECKING
Perform inspection as follows after removal, installation or replacement of camshaft or valve related parts, or if there is unusual engine conditions regarding valve clearance.
NOTE:
Check valve clearance while engine is cold and not running.
1. Remove the intake manifold collectors. Refer to Intake Manifold Collector.
2. Remove the ignition coils. Refer to Removal And Installation LH (LH) and Removal And Installation RH (RH).
3. Remove the rocker covers. Service and Repair.
4. Set No.1 cylinder at TDC on its compression stroke.
- Align pointer (A) with TDC mark on crankshaft pulley.
- Check that the valve lifters on No.1 cylinder are loose and valve lifters on No.4 are tight. If not, turn the crankshaft one full revolution (360�) and align as shown.
- RH cylinder head (1)
- White Arrow Indicates Engine front
5. Check only the valves as shown.
- Using a feeler gauge, measure the clearance between the valve lifter and camshaft.
- Record any valve clearance measurements which are out of specification. They will be used later to determine the required replacement lifter size.
6. Turn crankshaft 240�.
7. Set No.3 cylinder at TDC on its compression stroke.
8. Check only those valves as shown.
9. Turn the crankshaft 240� and align as above.
10. Set No.5 cylinder at TDC on its compression stroke.
11. Check only those valves as shown.
12. If all valve clearances are within specification, installation of the remaining components is in the reverse order of removal. If the valve clearances are out of specification, adjust the valve clearances.
VALVE ADJUSTING
CAUTION:
Adjust valve clearance while engine is cold.
NOTE:
- Perform adjustment by selecting the correct head thickness of the valve lifter (adjusting shims are not used).
- The specified valve lifter thickness is the dimension at normal temperatures. Ignore dimensional differences caused by temperature. Use specifications for hot engine condition to confirm valve clearances.
1. Remove the camshaft. Refer to Removal And Installation.
2. Remove the valve lifter that was measured as being outside the standard specifications.
3. Measure the center thickness of the removed lifter with a micrometer as shown.
4. Use the equation below to calculate valve lifter thickness for replacement.
- Thickness of new valve lifter can be identified by stamp marks on the reverse side (inside the cylinder).
Available thickness of valve lifter: 27 sizes with range 7.88 to 8.40 mm (0.3102 to 0.3307 in) in steps of 0.02 mm (0.0008 in) (when manufactured at factory). Refer to Maintenance.
CAUTION:
Install identification letter at the end and top, (U) and (N), at each of proper positions. (Be careful of mis-installation between intake and exhaust.)
5. Install the selected replacement valve lifter.
6. Install the camshaft. Refer to Removal And Installation.
7. Rotate the crankshaft a few turns by hand.
8. Confirm that the valve clearances are within specification.
9. After the engine has been run to full operating temperature, confirm that the valve clearances are within specification.
INSPECTION AFTER INSTALLATION
- Before starting engine, check the levels of engine coolant, engine oil and working fluid. If less than required quantity, fill to the specified level.
- Use procedure below to check for fuel leakage.
- Turn ignition switch ON (with engine stopped). With fuel pressure applied to fuel piping, check for fuel leakage at connection points.
- Start engine. With engine speed increased, check again for fuel leakage at connection points.
- Run engine to check for unusual noise and vibration.
- Warm up engine thoroughly to make sure there is no leakage of engine coolant, engine oil, working fluid, fuel and exhaust gas.
- Bleed air from passages in pipes and tubes of applicable lines, such as in cooling system.
- After cooling down engine, again check amounts of engine coolant, engine oil and working fluid. Refill to specified level, if necessary.
- Summary of the inspection items:
