Valve Clearance: Adjustments
CHECKINGCheck valve clearance while engine is warm but not running.
1. Remove rocker cover and all spark plugs.
2. Set No. 1 cylinder at TDC on its compression stroke.
- Align pointer with TDC mark on crankshaft pulley.
- Check that valve lifters on No. 1 cylinder are loose and valve lifters on No. 4 are tight.
If not, turn crankshaft one revolution (360°) and align as above.
3. Check only those valves shown in the figure
- Using a feeler gauge, measure clearance between valve lifter and camshaft.
- Record any valve clearance measurements which are out of specification. They will be used later to determine the required replacement adjusting shim.
Valve clearance (Hot):
Intake & Exhaust: 0.33 - 0.41 mm (0.013 - 0.016 inch)
4. Turn crankshaft one revolution (360°) and align mark on crankshaft pulley with pointer.
5. Check those valves shown in the figure.
- Use the same procedure as mentioned in step 4.
6. If all valve clearances are within specification, install the following parts.
- Rocker cover
- All spark plugs
ADJUSTING
Adjust valve clearance while engine is cold.
1. Turn crankshaft, to position cam lobe on camshaft of valve that must be adjusted upward.
2. Place Tool (A) around camshaft as shown in figure.
3. Rotate Tool (A) so that lifter is pushed down.
Before placing Tool (A), rotate notch toward center of cylinder head, to simplify shim removal later.
CAUTION: Be careful not to damage cam surface with Tool (A).
4. Place Tool (B) between camshaft and the edge of the valve lifter to retain valve lifter.
CAUTION:
- Tool (B) must be placed as close to camshaft bracket as possible.
- Be careful not to damage cam surface with Tool (B).
5. Remove Tool (A).
6. Remove adjusting shim using a small screwdriver and a magnetic finger.
7. Determine replacement adjusting shim size following formula.
a. Using a micrometer determine thickness of removed shim.
b. Calculate thickness of new adjusting shim so valve clearance comes within specified values.
R = Thickness of removed shim
N = Thickness of new shim
M = Measured valve clearance
Intake & Exhaust: N = R + [M - 0.37 mm (0.0146 inch)]
Shims are available in thicknesses from 1.96 mm (0.0772 inch) to 2.68 mm (0.1055 inch), in steps of 0.02 mm (0.0008 inch).
c. Select new shim with thickness as close as possible to calculated value.
8. Install new shim using a suitable tool.
- Install with the surface on which the thickness is stamped facing down.
9. Place Tool (A) as mentioned in steps 2 and 3.
10. Remove Tool (B).
11. Remove Tool (A).
12. Recheck valve clearance.