Checking and adjusting valve clearances on the G2.0–2.4DOHC engine

Note. Checking and adjusting valve clearances is performed on a cold engine (at a coolant temperature of 20°C) with the cylinder head installed.

1. Removing the decorative cover and cylinder head cover

1. Loosen the mounting bolts and remove the decorative engine cover (A).
2. Remove the cylinder head cover:
   • Disconnect the ignition coil connectors (A), then remove the coils, by unscrewing the corresponding mounting bolts;
   • 
   • 
   • Disconnect the positive crankcase ventilation hose (A) from the cylinder head cover;
   • 
   • Loosen the cylinder head cover mounting bolts, then remove the cover (A) and gasket.

2. Setting the cylinder #1 piston to TDC on the compression stroke

1. Turn the crankshaft pulley clockwise and align its groove with the timing mark "T" on the timing chain cover.
2. Make sure that the TDC marks (A) on the exhaust camshaft sprocket and on the timing chain clutch The variable valve timing (CVVT) valve timing on the intake camshaft is aligned with each other (aligned with the top plane of the cylinder head). If not aligned, rotate the crankshaft one revolution (360°).

3. Checking Valve Clearances

1. Check clearances only for the valves marked in the illustration (with cylinder 1 piston at TDC):
   • Intake valves of cylinders 1 and 2;
   • Exhaust valves of cylinders 1 and 3.

To measure clearances:

• Use a feeler gauge;
• Measure the clearance between the valve lifter and the surface of the rear (non-working) portion of the cam lobe.

2. Nominal clearances at a coolant temperature of 20°C:
   • Intake valves: 0.10–0.30 mm;
   • Exhaust valves: 0.20–0.40 mm.
   • 

Record the measurement results if the clearance does not meet the acceptable values. This information will be needed to select a new valve lifter.

3. Rotate the crankshaft pulley one revolution (360°) and align the groove on it with the timing mark "T" on the ignition timing indicator (scale on the timing chain cover).
4. Check the clearances only for the valves marked in the figure (with the piston of cylinder #4 at TDC):
   • intake valves of cylinders #3 and #4;
   • exhaust valves of cylinders #2 and #4.

Measure the gaps in the same way as in 3.1.

4. Adjusting the intake and exhaust valve clearances

1. Set the piston of cylinder #1 to TDC on the compression stroke.
2. Make sure the TDC marks on the exhaust camshaft sprocket and on the CVVT coupling of the intake camshaft are aligned with the top surface of the cylinder head.
3. Remove the bolt service hole on the timing chain cover.
   Caution! Do not reuse the bolt - replace it with a new one.

1. Insert a thin rod (pin) into the service hole on the timing chain cover to secure the chain tensioner plunger.
2. Secure the exhaust camshaft with a wrench and loosen the bolt sprocket mounts.
3. Remove the bolts and remove the camshaft bearing cap (A).

1. Loosen the bolts and remove the camshaft bearing caps (A) in the sequence shown in the figure.
2. Loosen and remove the intake camshaft bearing caps in the sequence shown in section 4.6.
3. Remove the camshafts, holding the timing chain from falling when disconnecting them from the sprockets.
4. Secure the timing chain with a rope.
   Note: Do not allow foreign objects to get behind the timing chain cover.
5. Using a micrometer, measure the thickness of the removed tappet valve.

1. Calculate the thickness of the new tappet to ensure the nominal clearance:
   • for the intake valve: N=T+[A−0.20]mm;
   • for the exhaust valve: N=T+[A−0.25]mm,

where:
T — thickness of the removed tappet;
A — measured valve clearance;
N — thickness of the new tappet.

13. Select a new valve tappet with a thickness as close as possible to the calculated one.
    Note: 41 tappet sizes are available in 0.015mm increments, ranging from 3.00mm to 3.60mm.
14. Install the selected valve tappet, first applying a small amount of engine oil.
15. Holding the timing chain, place the intake camshaft on the cylinder head.
16. Install the timing chain on the intake camshaft.

13. Install the exhaust camshaft, aligning the marks (A) indicating the relative position of the chain and the camshaft sprocket.
14. Install and tighten (in several steps) the camshaft bearing caps to the specified torque in the sequence shown in the figure:
    • M6 bolt: 11–13 N⋅m;
    • M8 bolt: 28–31 N⋅m.
    • 
15. Remove the thin rod (pin) from the service hole on the timing chain cover (installed in step 4.4), then install a new service hole bolt. Tightening torque: 12–15 N⋅m.

5. Rechecking the valve clearances

1. Turn the crankshaft pulley clockwise two turns.
2. Check:
   • alignment of the relative position marks of the chain and camshaft sprockets;
   • alignment of the groove on the crankshaft pulley with the timing mark "O" on the ignition timing indicator (scale on the timing chain cover).
3. After adjustment, recheck the valve clearances.
   Nominal clearances after adjustment (at a coolant temperature of 20°t{C}):
   • intake valves: 0.17–0.23 mm;
   • exhaust valves: 0.27–0.33 mm.

6. Installing the Cylinder Head Cover

1. Remove any remaining old gasket and sealant from the mating surfaces of the timing chain cover and cylinder head cover.
2. Install the new gasket in the groove of the cylinder head cover.
3. Degrease the surface before applying the sealant.
4. Apply Loctite 5900 sealant in a continuous bead 2.0–2.5 mm in diameter to the mating surface of the timing chain cover (see figure).
   Note: Before applying the sealant, ensure the mating surfaces are dry and clean.

Caution:

• Install and secure the cylinder head cover within 5 minutes after applying the sealant;
• Wait at least 30 minutes before adding engine oil.

1. Install the cylinder head cover with a new gasket and tighten the bolts to the specified torque in two passes in the sequence shown in the figure:
   • Pass 1: 4–6 N⋅m;
   • Pass 2: 8–10 N⋅m.
   • 

7. Finishing Operations

1. Connect the positive crankcase ventilation hose to the cylinder head cover.
2. Install the ignition coils, tighten the corresponding mounting bolts to the specified torque, and connect the connectors. Tightening torque: 10–12 N⋅m.
3. Install the engine cover. Tightening torque: 8–12 N⋅m.