Valve Clearance: Service and Repair
CAMSHAFT VALVE CLEARANCE
Inspection
INSPECTION
Check valve clearance if applicable to the following cases:
- At the removal and installation of VVEL ladder assembly or valve-related parts, or at the occurrence of malfunction (poor starting, idle malfunction, unusual noise) due to aged deterioration in valve clearance.
CAUTION:
Valve clearance check on the intake side is not required after replacing the VVEL ladder assembly &
cylinder head assembly with a new one. (Install new VVEL ladder assembly & cylinder head assembly in factory-shipped condition because it is factory-adjusted and inspected.)
NOTE:
VVEL ladder assembly cannot be replaced as a single part, because it is machined together with cylinder head assembly.
- At the removal, installation, and replacement of exhaust camshaft or valve-related parts, or at the occurrence of malfunction (poor starting, idle malfunction, unusual noise) due to aged deterioration in valve clearance.
1.Remove VVEL actuator motor assembly. Refer to "Removal and Installation" Removal and Installation.
2.Remove rocker covers (bank 1 and bank 2). Refer to "Removal and Installation" Removal and Installation.
3.Remove VVEL actuator housing assembly. Refer to "Removal and Installation" Removal and Installation.
4.Measure the valve clearance as per the following:
- Use the feeler gauge (commercial service tool) of curved-tip. This allows the feeler gauge to access the clearance between camshaft (drive shaft) nose and valve lifter with ease.
Valve clearance: Refer to "Camshaft" [1][2]Camshaft, Engine.
NOTE:
Be sure to note the following points when measuring valve clearance on the intake side.
- Before measuring, check that the position of drive shaft nose is within the angle shown in the figure.
- Refer to the figure for the insertion direction of the feeler gauge since the direction depends on the bank.
a.Set No. 1 cylinder at TDC of its compression stroke.
- Rotate crankshaft pulley clockwise to align timing mark (grooved line without color) (B) with timing indicator (A).
- Check that exhaust cam nose on No. 1 cylinder (engine front side of bank 1) is located as shown in the figure.
- If not, turn crankshaft one revolution (360 degrees) and align as shown in the figure.
- 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
NOTE:
To measure valve clearance of No. 1 cylinder INT valve (front side), insert feeler gauge (A) (commercial service tool) as shown in the figure.
b.Rotate crankshaft 270 degrees clockwise (when viewed from engine front) to align No. 3 cylinder at TDC
its compression stroke.
NOTE:
Crankshaft pulley mounting bolt flange has an angle mark (B)
every 90 degrees (c). They can be used as a guide to rotation angle.
- 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
c.Rotate crankshaft 90 degrees clockwise (when viewed from engine front) to align No. 6 cylinder at TDC of compression stroke.
NOTE:
Crankshaft pulley mounting bolt flange has an angle mark (B)
every 90 degrees (c). They can be used as a guide to rotation angle.
- By referring to the figure, measure the valve clearances at locations marked "�" as shown in the table below (locations indicated in the figure).
- No. 6 cylinder at compression TDC
5.Perform adjustment or replacement if the measured value is out of the standard.
- If a valve clearance on the exhaust side is out of specification, adjust the valve clearance. Refer to EM80, "Inspection".
- If a valve clearance on the intake side is out of specification, replace VVEL ladder assembly & cylinder head assembly. Refer to "Exploded View" Exploded View.
CAUTION:
Never adjust valve clearance on the intake side.
NOTE:
Since the valve lifter (INT) cannot be replaced by the piece, VVEL ladder assembly & cylinder head assembly replacement are required.