Valve And Valve Spring

1. Inspect valve stems and valve guides.
   1. Using a caliper gauge, measure the inside diameter of the valve guide.

      Valve guide I.D. 

      Intake/Exhaust : 5.500 ~ 5.512mm (0.216 ~ 0.217in.)

      Fig 1: Measuring Inside Diameter Of Valve Guide

      Courtesy of HYUNDAI MOTOR CO.
   2. Using a micrometer, measure the diameter of the valve stem.

      Valve stem O.D. 

      Intake : 5.465 ~ 5.480mm (0.2151 ~ 0.2157in.)

      Exhaust : 5.458 ~ 5.470mm (0.2149 ~ 0.2153in.)

      Fig 2: Measuring Diameter Of Valve Stem

      Courtesy of HYUNDAI MOTOR CO.
   3. Subtract the valve stem diameter measurement from the valve guide inside diameter measurement.

   Valve stem-to-guide clearance 

   [Standard]

   Intake : 0.020 ~ 0.047mm (0.0008 ~ 0.0018in.)

   Exhaust : 0.030 ~ 0.054mm (0.0012 ~ 0.0021in.)

   [Limit]

   Intake : 0.07mm (0.0027in.)

   Exhaust : 0.09mm (0.0035in.)

2. Inspect valves.
   1. Check the valve is ground to the correct valve face angle.
   2. Check that the surface of the valve for wear.

      If the valve face is worn, replace the valve.

   3. Check the valve head margin thickness.

      If the margin thickness is less than minimum, replace the valve.

      Margin 

      [Standard]

      Intake : 1.56 ~ 1.86mm(0.06142 ~ 0.07323in.)

      Exhaust : 1.73 ~ 2.03mm(0.06811 ~ 0.07992in.)

      Fig 3: Checking Valve Head Margin Thickness

      Courtesy of HYUNDAI MOTOR CO.
   4. Check the valve length.

      Length 

      Intake : 105.27mm (4.1445in)

      Exhaust : 105.50mm (4.1535in)

   5. Check the surface of the valve stem tip for wear.

   If the valve stem tip is worn, replace the valve.

3. Inspect valve seats

   Check the valve seat for evidence of overheating and improper contact with the valve face.

   If the valve seat is worn, replace cylinder head.

   Before reconditioning the seat, check the valve guide for wear. If the valve guide is worn, replace cylinder head.

   Recondition the valve seat with a valve seat grinder or cutter. The valve seat contact width should be within specifications and centered on the valve face.

4. Inspect valve springs.

1. Using a steel square, measure the out-of-square of the valve spring.
2. Using vernier calipers, measure the free length of the valve spring.

Valve spring 

[Standard]

Free height : 43.86mm (1.7267in.)

Out-of-square : 1.5°

Fig 4: Measuring Free Length Of Valve Spring

Courtesy of HYUNDAI MOTOR CO.