Valve Clearance Adjustment

Valve Clearance Inspection and Adjustment (MLA)

Inspect and adjust the valve clearance with the engine cold (engine coolant temperature: 20 °C) and the cylinder head installed to the cylinder block.

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 damper pulley clockwise and align its groove with the "T" alignment mark on the lower timing chain cover.

      

   2. Check that the camshaft sprocket mark is in a straight line with the cylinder head surface, as shown in the illustration. If not, turn the crankshaft clockwise one full turn (360°). [LH exhaust]

      

      [LH exhaust]

      

      [intake RH]

      

      [RH exhaust]

      

      Do not turn the engine counterclockwise.

3. 3
   Inspect the valve clearance.

   1. Set No. 1 cylinder to TDC, then inspect the valve clearances shown below only. [Left]

      

      

      

      [RH]

      

      

      

      How to measure:

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

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

      Valve Clearance (engine coolant temperature: 20 °C [68°F]) [Specification] 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 clockwise one revolution (360°) and align the groove with the "T" timing mark on the lower timing chain cover.
   3. With No. 4 cylinder at TDC, inspect the valve clearances shown in the illustration below only. (Refer to step 1 of the procedure.) [Left]

      

      

      [RH]

      

      

4. 4
   Adjust the intake and exhaust valve clearance.

   1. Set the No. 1 cylinder to TDC/compression.
   2. Remove the camshaft assembly. (Refer to Cylinder Head Assembly – "CVVT and Camshaft")
   3. Remove the tappets.
   4. Measure the thickness of the removed tappet using a micrometer.

      

   5. Calculate the thickness of the new tappet so that the valve clearance falls within the specified value. 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.)]
   6. Select a new tappet with a thickness as close as possible to the calculated value.

      Tappets are available in 41 steps of 0.015 mm (0.0006 in.) from 3.00 mm (0.1181 in.) to 3.60 mm (0.1417 in.).

   7. Install the new tappet into the cylinder head.

      Apply engine oil around and on top of the selected tappet.

   8. Install the intake and exhaust camshafts.
   9. Install the bearing caps. (Refer to Cylinder Head Assembly – "CVVT and Camshaft")
   10. Install the timing chain. (Refer to Timing System - Timing Chain)
   11. Rotate the crankshaft two revolutions in the normal direction of rotation (clockwise) and align the timing marks of the crankshaft and camshaft sprockets. [LH side]

       

       [LH exhaust]

       

       [intake RH]

       

       [RH exhaust]

       

   12. Recheck the valve clearance. Valve Clearance (engine coolant temperature: 20 °C [68°F]) [Specification] Intake: 0.17–0.23 mm (0.0067–0.0090 in.) Exhaust: 0.27–0.33 mm (0.0106–0.0129 in.)