Valve Clearance: Service and Repair
CAMSHAFT VALVE CLEARANCE
Inspection
INSPECTION
Check valve clearance if applicable to the following cases:
Intake side:
- 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.
Exhaust side:
- At the removal, installation, and replacement of camshaft (EXH) 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 rocker covers (bank 1 and bank 2). Removal And Installation.
2. 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.
A : Bank 2
B : Feeler gauge (commercial service tool)
c : 45 degrees (drive shaft nose angle)
D : View D
White arrow : Insertion direction of feeler gauge on the bank 2
Black arrow : Insertion direction of feeler gauge on the bank 1
- 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.
1 : Camshaft (EXH) (bank 1)
Arrow : Engine front
- 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 "x" as shown in the table below (locations indicated in the figure).
Arrow: Engine front
- No. 1 cylinder at compression TDC
NOTE:
To measure valve clearance of No. 1 cylinder INT valve (front side), insert feeler gauge (commercial service tool) from the front side (A) of the control shaft bracket or camshaft (EXH) side
(B).
1 : Valve lifter
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.
A : Paint mark
- By referring to the figure, measure the valve clearances at locations marked "x" as shown in the table below (locations indicated in the figure).
Arrow: Engine front
- 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.
A : Paint mark
- By referring to the figure, measure the valve clearances at locations marked "x" as shown in the table below (locations indicated in the figure).
Arrow: Engine front
- No. 6 cylinder at compression TDC
3. 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. Inspection.
- If a valve clearance on the intake side is out of specification, replace VVEL ladder assembly & cylinder head assembly. 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.