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 :
  
  6.000~6.015mm (0.2362~0.2368in)
  
  Fig 1: Measuring Inner Diameter Of Valve Guide
  Courtesy of KIA MOTORS AMERICA, INC.
2. Using a micrometer, measure the outer diameter of valve stem.
  Valve stem outer diameter
  
  Intake: 5.965~5.980mm (0.2348~0.2354in)
  
  Exhaust: 5.950~5.965mm (0.2343 - 0.2348in)
  
  Fig 2: Measuring Outer Diameter Of Valve Stem
  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
  
  Standard
  
  Intake: 0.02~0.05mm (0.0008~0.0020in)
  
  Exhaust: 0.035~0.065mm (0.0014~0.0026in)
  
  Limit
  
  Intake: 0.10mm (0.0039in)
  
  Exhaust: 0.15mm (0.0059in)
  
  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 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: 1.1mm (0.0433in)
  
  Exhaust: 1.3mm (0.0512in)
  
  Limit
  
  Intake: 0.8mm (0.0315in)
  
  Exhaust: 1.0mm (0.0394in)
  
  Fig 3: Identifying Valve Head Margin Thickness
  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 With Valve Seat Grinder Or Cutter
  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 a vernier calipers, measure the free length of valve spring.
  Valve spring Standard
  
  Free height: 44mm (1.7323in)
  
  Load: 21.6±1.1kg/35.0mm (47.6±2.4lb/1.3780in)
  
  45.1 ±2.2kg/27.2mm (99.4±4.9lb/1.0709in)
  
  Out of square: Less than 1.5°
  
  Limit
  
  Out of square: 3°
  
  Fig 5: Measuring Free Length Of Valve Spring
  Courtesy of KIA MOTORS AMERICA, INC.
  
  If the loads is not as specified, replace the valve spring.