Valve Clearance: Adjustments

VALVE CLEARANCE INSPECTION AND ADJUSTMENT

NOTE:
Inspect and adjust the valve clearance when the engine is cold (Engine coolant temperature : 20°C) and cylinder head is installed on the cylinder block.

1. Remove the engine cover.
2. Remove air cleaner assembly.
3. Remove the surge tank.
4. Remove the cylinder head cover.
(1) Disconnect the ignition coil connector and remove the ignition coil.
(2) Disconnect the breather pipe assembly(A) from the cylinder head cover.




(3) Loosen the cylinder head cover bolts and then remove the cover(A) and gasket.




5. Set No.1 cylinder to TDC/compression.
(1) Turn the crankshaft pulley and align its groove with the timing mark "T" of the lower timing chain cover.




(2) Check that the mark(A) of the camshaft timing sprockets are in straight line on the cylinder head surface as shown in the illustration.
If not, turn the crankshaft one revolution (360°)

NOTE:
Do not rotate engine counterclockwise





6. Inspect the valve clearance.
(1) Check only the valve indicated as shown. [No. 1 cylinder : TDC/Compression] measure the valve clearance.




Measurement method.
A. - Using a thickness gauge, measure the clearance between the tappet and the base circle of camshaft.
- Record the out-of-specification valve clearance measurements. They will be used later to determine the required replacement adjusting tappet.

Valve clearance
Specification
Engine coolant temperature : 20°C [68°F]
Limit
Intake : 0.17 - 0.23mm (0.0067 - 0.0090in.)
Exhaust : 0.27 - 0.33mm (0.0106 - 0.0129in.)


(2) Turn the crankshaft pulley one revolution (360°) and align the groove with timing mark "T" of the lower timing chain cover.

NOTE:
Do not rotate engine counterclockwise

(3) Check only valves indicated as shown. [NO. 4 cylinder : TDC/compression]. Measure the valve clearance. )




7. Adjust the intake and exhaust valve clearance.
(1) Set the No.1 cylinder to the TDC/compression.
(2) Remove the timing chain.

NOTE:
Before removing the timing chain, mark the RH/LH timing chain with an identification based on the location of the sprocket because the identification mark on the chain for TDC(Top Dead Center) can be erased.

(3) Remove the camshaft bearing caps(A).




(4) Remove the camshaft assembly(A).




(5) Remove MLAs.
(6) Measure the thickness of the removed tappet using a micrometer.




(7) Calculate the thickness of a new tappet so that the valve clearance comes within the specified value.

Valve clearance(Engine coolant temperature: 20°C[68°F])
T : Thickness of removed tappet
A : Measured valve clearance
N : Thickness of new tappet
Intake : N = T + [A - 0.20mm(0.0079in.)]
Exhaust : N = T + [A - 0.30mm (0.0118in.)]


(8) Select a new tappet with a thickness as close as possible to the calculated value.

NOTE:
Shims are available in 41size increments of 0.015mm (0.0006in.) from 3.00mm (0.118in.) to 3.600mm (0.1417in.)

(9) Place a new tappet on the cylinder head.

NOTE:
Apply engine oil at the selected tappet on the periphery and top surface.

(10) Install the intake and exhaust camshaft.
(11) Install the bearing caps .
(12) Install the timing chain .
(13) Turn the crankshaft two turns in the operating direction(clockwise) and realign crankshaft sprocket and camshaft sprocket timing marks(A).




(14) Recheck the valve clearance.

Valve clearance (Engine coolant temperature: 20°C[68°F])
[Specification]
Intake : 0.17 - 0.23mm (0.0067 - 0.0090in.)
Exhaust : 0.27 - 0.33mm (0.0106 - 0.0129in.)