Valve Clearance: Adjustments
VALVE CLEARANCE INSPECTION AND ADJUSTMENTMLA (MECHANICAL LASH ADJUSTER)
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(A).
2. Remove the cylinder head cover.
1) Disconnect the ignition coil connector(A) and remove the ignition coil.
2) Disconnect the P.C.V hose(A) and the breather hose from the cylinder head cover.
3) Loosen the cylinder head cover bolts and then remove the cover(A) and gasket.
3. 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°)
4. Inspect the valve clearance.
1) Check only the valve indicated as shown. [No. 1 cylinder: TDC/Compression] measure the valve clearance.
^ 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: 0.10 - 0.30mm (0.0039 - 0.0118in.)
Exhaust: 0.20 - 0.40mm (0.0079 - 0.0157in.)
2) Turn the crankshaft pulley one revolution (360°) and align the groove with timing mark "T' of the lower timing chain cover.
3) Check only valves indicated as shown. [NO. 4 cylinder: TDC/compression]. Measure the valve clearance.
5. Adjust the intake and exhaust valve clearance.
1) Set the No.1 cylinder to the TDC/compression.
2) Marks on the timing chain and camshaft timing sprockets.
3) Turn the crankshaft pulley 15° clockwise.
4) Remove the service hole bolt(A) of the timing chain cover.
CAUTION
The service hole bolt must not be reused once it has been assembled.
5) Insert a thin rod in the service hole of the timing chain cover and release the ratchet.
6) Remove the front camshaft bearing cap(A).
7) Remove the exhaust camshaft sprocket.
8) Remove the exhaust camshaft bearing cap and exhaust camshaft.
9) Remove the intake camshaft bearing cap and intake camshaft.
CAUTION
When disconnect the timing chain from the camshaft timing sprocket, hold the timing chain.
10) Secure the timing chain.
CAUTION
Be careful not to drop anything inside timing chain cover.
11) Measure the thickness of the removed tappet using a micrometer.
12) Calculate the thickness of a new tappet so that the valve clearance comes within the specified value.
Valve clearance (Engine coolant temperature: 20°C)
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.)]
13) Select a new tappet with a thickness as close as possible to the calculated value.
NOTE
Tappets are available in 47size increments of 0.015mm (0.0006in.) from 3.00mm (0.118in.) to 3.690mm (0.1452in.)
14) Place a new tappet on the cylinder head.
15) Hold the timing chain, and install the intake camshaft and timing sprocket assembly.
16) Align the match marks on the timing chain and camshaft timing sprocket.
17) Install the intake and exhaust camshaft.
18) Install the front bearing cap.
19) Install the service hole bolt.
Tightening torque
12 - 15N.m (1.2 - 1.5kgf.m, 8.8 - 11.0lb-ft)
20) Turn the crankshaft two turns in the operating direction(clockwise) and realign crankshaft sprocket and camshaft sprocket timing marks.
21) Recheck the valve clearance.
Valve clearance (Engine coolant temperature: 20°C)
[Specification]
Intake: 0.17 - 0.23mm (0.0067 - 0.0090in.)
Exhaust: 0.27 - 0.33mm (0.0106 - 0.0129in.)