Cylinder Head Assembly

Components and Component Location

Components

Valve Clearance Inspection and Adjustment

Valve Clearance Inspection and Adjustment

1. 1

   Remove the cylinder head cover.

   (Refer to Cylinder Head Assembly - "Cylinder Head Cover")

2. 2

   Set the No. 1 cylinder to TDC/compression.

   1. Turn the crankshaft pulley and align its groove with the "T" mark on the timing chain lower cover.

      

   2. Remove the timing chain cover.

      (See Valve Timing - "Timing Chain Cover")

   3. Make sure the TDC marks (A) on the CVVT sprockets are aligned in a straight line with the surface of the cylinder head, as shown in the illustration.

      Otherwise, rotate the crankshaft one full turn (360°).

      

3. 3

   Inspect the valve clearance.

   1. Check only the valve indicated in the illustration. Measure the valve clearance.

      

      • Using a thickness gauge, measure the clearance between the lash adjuster and the camshaft base circle.

      • Record the valve clearance measurements that are out of specification. They will be used later to determine the required replacement tappet.

      Valve Clearance

      Specification

      Engine coolant temperature: 20 °C [68°F]

      Limit

      Intake: 0.10–0.30 mm (0.0039–0.0118 in.)

      Exhaust: 0.20–0.40 mm (0.0079–0.0157 in.)

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

   3. Check only the valves indicated in the illustration. Measure the valve clearance.

      

4. 4

   Adjust the intake and exhaust valve clearance.

   1. Remove the camshaft assembly.

      (Refer to Cylinder Head Assembly - "CVVT and Camshaft")

   2. Measure the thickness of the removed tappet using a micrometer.

      

   3. Calculate the thickness of the new tappet so that the valve clearance falls within the specified value.

      Valve Clearance [Engine Coolant Temperature: 20 °C]

      T: Thickness of the removed tappet

      A: Measured valve clearance

      N: Thickness of the new tappet

      Intake: N = T + [A - 0.20 mm (0.0079 in.)]

      Exhaust: N = T + [A - 0.30 mm (0.0118 in.)]

   4. Select a new tappet with a thickness as close as possible to the calculated value.

   5. Install the new tappet into the cylinder head.

   6. Install the camshaft assembly.

      (Refer to Cylinder Head Assembly - "Camshaft")

   7. Turn the crankshaft two revolutions in the direction of rotation (clockwise), then make sure the TDC marks (A) on the CVVT sprockets are aligned in a straight line with the surface of the cylinder head.

      

   8. Recheck the valve clearance.

      Valve Clearance [Engine Coolant Temperature: 20 °C]

      [Specification]

      Intake: 0.17–0.23 mm (0.0067–0.0090 in.)

      Exhaust: 0.32–0.38 mm (0.0126–0.0150 in.)