Valve And Valve Spring

Inspect the valve stems and valve guides.
1. Using a caliper gauge, measure the inner diameter of valve guide.
  Valve guide inner diameter: 6.000-6.015 mm (0.2362-0.2368 in)
  
  Fig 1: Measuring Valve Guide Clearance
  Courtesy of KIA MOTORS AMERICA, INC.
2. Using a micrometer, measure the outer diameter of valve stem.
  Valve stem outer diameter:
  
  Intake: 5.965-5.980 mm (0.2348-0.2354 in)
  
  Exhaust: 5.950-5.965 mm (0.2343-0.2348 in)
  
  Fig 2: Measuring Valve Stem Diameter
  Courtesy of KIA MOTORS AMERICA, INC.
3. Subtract the valve stem outer diameter measurement from the valve guide inner diameter measurement.
  Valve stem- to-guide clearance
  1. Standard
  2. Intake: 0.020-0.050 mm (0.0008-0.0020 in)
  3. Exhaust: 0.035-0.065 mm (0.0014-0.0026 in)
  1. Limit
  2. Intake: 0.10 mm (0.0039 in)
  3. Exhaust: 0.13 mm (0.0051 in)
  If the clearance is greater than maximum, replace the valve and valve guide.
Inspect the valves.
1. Check the valve is ground to the correct valve face angle.
2. Check the surface of the valve face for damage or wear.
  If the valve face is damaged or worn, replace the valve.
3. Check the valve head margin thickness.
  If the margin thickness is less than minimum, replace the valve.
  1. Margin Standard
  2. Intake: 1.15 mm (0.0453 in)
  3. Exhaust: 1.35 mm (0.0531 in)
  1. Limit
  2. Intake: 0.8 mm (0.0315 in)
  3. Exhaust: 1.0 mm (0.0394 in)
  Fig 3: Measuring Valve Margin
  Courtesy of KIA MOTORS AMERICA, INC.
4. Check the surface of valve stem tip for wear. If the valve stem tip is worn, replace the valve.
Inspect the valve seats.
1. Check the valve seat for evidence of overheating and improper contact with the valve face. Replace the seat if necessary.
2. Before reconditioning the seat, check the valve guide for wear. If the valve guide is worn, replace it, then recondition the seat.
3. 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.
  
  Fig 4: Reconditioning Valve Seat
  Courtesy of KIA MOTORS AMERICA, INC.
Inspect the valve springs.
1. Using a steel square, measure the out-of-square of valve spring.
2. Using vernier calipers, measure the free length of valve spring.
  1. Valve spring standard
  2. Free height: 48.8 6 mm (1.9236 in)
  3. Load: 18.8+/-0.9 kg/39.0 mm (41.4+/-2.0 lb/1.5354 in) 41.0+/-1.5 kg/30.5 mm (90.4+/-3.3 lb/1.2008 in)
  4. Out of square: Less than 1.5°
  5. Limit: Out of square: 3°
  Fig 5: Measuring Valve Springs
  Courtesy of KIA MOTORS AMERICA, INC.
  
  If the loads is not as specified, replace the valve spring.