Valve Clearance: Testing and Inspection

CAMSHAFT VALVE CLEARANCE

Inspection and Adjustment

INSPECTION
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.

In cases of removing/installing or replacing camshaft and valve related parts, or of unusual engine conditions due to changes in valve clearance (found malfunctions during stating, idling or causing noise), perform inspection as follows:
1. Remove rocker covers (bank 1 and bank 2). Refer to Removal and Installation.
2. Measure the valve clearance as per the following:
a. Set No. 1 cylinder at TDC of its compression stroke.

- Rotate crankshaft pulley clockwise to align timing mark
(grooved line without color) with timing indicator.

- Check that intake and exhaust cam nose on No. 1 cylinder
(engine front side of bank 1) are located as shown in the figure.
- If not, turn crankshaft one revolution (360 degrees) and align as shown in the figure.

b. Use a feeler gauge, measure the clearance between valve lifter and camshaft.

Valve clearance : Refer to "Camshaft". Specifications

- By referring to the figure, measure the valve clearances at locations marked "�" as shown in the table below (locations indicated in the figure).
- No. 1 cylinder at compression TDC

c. Rotate crankshaft 240 degrees clockwise (when viewed from engine front) to align No. 3 cylinder at TDC its compression stroke.

NOTE:
Mark a position 240 degrees (b) from a corner of the hexagonal part of crankshaft pulley mounting bolt as shown in the figure.

Use the hexagonal part as a guide.
- By referring to the figure, measure the valve clearances at locations marked "�" as shown in the table below (locations indicated in the figure).
- No. 3 cylinder at compression TDC

d. Rotate crankshaft 240 degrees clockwise (when viewed from engine front) to align No. 5 cylinder at TDC of compression stroke.

NOTE:
Mark a position 240 degrees (b) from a corner of the hexagonal part of crankshaft pulley mounting bolt as shown in the figure.

3. Perform adjustment if the measured value is out of the standard. Refer to "ADJUSTMENT".

ADJUSTMENT
- Perform adjustment depending on selected head thickness of valve lifter.
1. Measure the valve clearance. Refer to "INSPECTION".
2. Remove camshaft. Refer to Removal and Installation.
3. Remove valve lifters at the locations that are out of the standard.

4. Measure the center thickness of the removed valve lifters with a micrometer (A).
5. Use the equation below to calculate valve lifter thickness for replacement.

Valve lifter thickness calculation: t = t1 + (C1 - C2)
t = Valve lifter thickness to be replaced
t1 = Removed valve lifter thickness
C1 = Measured valve clearance
C2 = Standard valve clearance:
Intake : 0.30 mm (0.012 in)
Exhaust : 0.33 mm (0.013 in)

- Thickness of new valve lifter can be identified by stamp marks on the reverse side (inside the cylinder).
Stamp mark 788 indicates 7.88 mm (0.3102 in) in thickness.
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 Specifications.
6. Install selected valve lifter.
7. Install camshaft. Refer to Removal and Installation.
8. Manually turn crankshaft pulley a few turns.
9. Check that the valve clearances for cold engine are within the specifications by referring to the specified values. Refer to Testing and Inspection.
10. Install all removal parts in the reverse order of removal.
11. Warm up the engine, and check for unusual noise and vibration.