Valve Guide

WARNING: This page is about a different car, the 2012 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.

Check the clearance between valve guide and valve stem. Check the clearance between valve guide and valve stem by measuring respectively the outer diameter of valve stem and the inner diameter of valve guide.
1. Measure the outer diameter of valve stem with a micrometer. If it is not within the standard, replace the valve.
  NOTE:
  - Measurement should be performed at a temperature of 20°C (68°F).
  - Measure the outer diameter of the valve stem at the three places as shown in the figure, and take the value of most worn location.
  - If the valve is replaced, put a small amount of grinding compound on the valve seat surface of cylinder head, and lap the valve and valve seat surfaces. Replace with a new valve oil seal after lapping. For replacement of valve oil seal, refer to the "INTAKE VALVE OIL SEAL AND EXHAUST VALVE OIL SEAL". < refer to INTAKE VALVE OIL SEAL AND EXHAUST VALVE OIL SEAL , INSPECTION, Cylinder Head >
  Valve stem outer diameters:
  
  Standard
  
  Intake
  
  5.455 - 5.470 mm (0.2148 - 0.2154 in)
  
  Exhaust
  
  5.445 - 5.460 mm (0.2144 - 0.2150 in)
  
  Fig 1: Measuring Outer Diameter Of Valve Stem Using Micrometer
  Courtesy of SUBARU OF AMERICA, INC.
2. Using a caliper gauge, measure the inner diameter of valve guide. If it is not within the standard, replace the valve guide. For replacement procedure, refer to step 2).
  NOTE: Measurement should be performed at a temperature of 20°C (68°F).
  
  Valve guide inner diameter:
  
  Standard
  
  5.500 - 5.512 mm (0.2165 - 0.2770 in)
  
  Fig 2: Measuring Inner Diameter Of Valve Guide Using Caliper Gauge
  Courtesy of SUBARU OF AMERICA, INC.
3. Calculate the clearance between valve guide and valve stem.
  Clearance between the valve guide and valve stem:
  
  Standard
  
  Intake
  
  0.030 - 0.057 mm (0.0012 - 0.0022 in)
  
  Exhaust
  
  0.040 - 0.067 mm (0.0016 - 0.0026 in)
If the clearance between valve guide and valve stem exceeds the standard, replace the valve guide or valve, whichever shows the greater amount of wear or damage. For replacement procedure of valve guide, refer to the following.
NOTE: If the valve is replaced, put a small amount of grinding compound on the valve seat surface of cylinder head, and lap the valve and valve seat surfaces. Replace with a new valve oil seal after lapping. For replacement of valve oil seal, refer to the "INTAKE VALVE OIL SEAL AND EXHAUST VALVE OIL SEAL". < refer to INTAKE VALVE OIL SEAL AND EXHAUST VALVE OIL SEAL , INSPECTION, Cylinder Head >
1. Insert ST into the valve guide with the combustion chamber upward and remove the valve guide using plastic hammer.
  CAUTION:
  - Place a wood board wrapped with a waste cloth to stabilize the cylinder head before work.
  - Use special care not to damage the cylinder head during work.
  ST 499765700 VALVE GUIDE REMOVER AND INSTALLER
  
  Fig 3: Removing Valve Guide Using Plastic Hammer
  Courtesy of SUBARU OF AMERICA, INC.
2. Before installing the valve guide, make sure that neither scratches nor damages exist on the inner surface of valve guide holes in cylinder head.
3. Draw a reference line (A) for insert on the valve guide using a marker as shown in the figure.
  NOTE:
  - Use a new valve guide.
  - A reference line for insert is used as a guide when tapping-in the valve guide.
  Valve guide inserting reference line position L: 15 mm (0.5906 in)
  
  Fig 4: Identifying Valve Guide Inserting Reference Line Position
  Courtesy of SUBARU OF AMERICA, INC.
4. Apply a enough coat of engine oil to the valve guide, and set the valve guide on the cylinder head with the combustion chamber downward.
5. Insert the ST into the valve guide, and tap-in the valve guide to the reference line (A) for insert using plastic hammer.
  CAUTION:
  - During work, place a waste cloth, etc. to avoid scratching the mating surface of the cylinder head.
  - Use special care not to damage the cylinder head during work.
  ST 499765700 VALVE GUIDE REMOVER AND INSTALLER
  
  Fig 5: Inserting ST Into Valve Guide
  Courtesy of SUBARU OF AMERICA, INC.
6. Measure the valve guide protrusion amount "L" as shown in the figure using a caliper gauge. Insert the ST into the valve guide again, and tap-in the valve guide so that it is positioned within standard by referring to the measured value using plastic hammer.
  CAUTION:
  - During work, place a waste cloth, etc. to avoid scratching the mating surface of the cylinder head.
  - Use special care not to damage the cylinder head during work.
  NOTE: Be careful not to tap-in excessively by repeating the steps of Tapping-in → Measurement → Tapping-in → Measurement... when installing the valve guide.
  
  ST 499765700 VALVE GUIDE REMOVER AND INSTALLER
  
  Valve guide protrusion amount L:
  
  Standard
  
  11.4 - 11.8 mm (0.449 - 0.465 in)
  
  Fig 6: Measuring Valve Guide Protrusion Amount Using Caliper Gauge
  Courtesy of SUBARU OF AMERICA, INC.
  
  Fig 7: Inserting ST Into Valve Guide
  Courtesy of SUBARU OF AMERICA, INC.
7. Ream the inside of valve guide with the combustion chamber upward using ST. Put the ST in valve guide, and rotate the ST slowly clockwise while pushing it lightly. Bring the ST back while rotating it clockwise.
  CAUTION:
  - Place a wood board wrapped with a waste cloth to stabilize the cylinder head before work.
  - Use special care not to damage the cylinder head during work.
  NOTE:
  - Apply engine oil to the ST when reaming.
  - If the inner surface of valve guide is damaged, the edge of ST should be slightly ground with oil stone.
  - If the inner surface of valve guide becomes lustrous and the ST does not chip, use a new ST or remedy the ST.
  ST 499765900 VALVE GUIDE REAMER
  
  Fig 8: Reaming Inside Of Valve Guide Using Valve Guide Reamer
  Courtesy of SUBARU OF AMERICA, INC.
8. After reaming, clean the valve guide to remove chips.
9. Recheck the contact condition between valve and valve seat after replacing the valve guide.