Valve Guide

WARNING: This page is about a different variant/trim than selected.

Check the clearance between valve guide and stem. The clearance can be checked by measuring respectively the outer diameter of valve stem and inner diameter of valve guide with a micrometer.
Clearance between the valve guide and valve stem:

Standard

Intake 0.035 - 0.062 mm (0.0014 - 0.0024 in)

Exhaust 0.040 - 0.067 mm (0.0016 - 0.0026 in)

Fig 1: Measuring Inner Diameter Of Valve Guide
Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Measuring Outer Diameter Of Valve Stem
Courtesy of SUBARU OF AMERICA, INC.
If the clearance between valve guide and stem exceeds the standard value, replace the valve guide or valve itself whichever shows greater amount of wear. See the following procedure for valve guide replacement.
Valve guide inner diameter:

6.000 - 6.012 mm (0.2362 - 0.2367 in)

Valve stem outer diameters:

Intake

5.950 - 5.965 mm (0.2343 - 0.2348 in)

Exhaust

5.945 - 5.960 mm (0.2341 - 0.2346 in)
1. Place the cylinder head on ST1 with the combustion chamber upward so that valve guides enter the holes in ST1.
2. Insert ST2 into the valve guide and press it down to remove the valve guide.
  ST1 498267800 CYLINDER HEAD TABLE
  
  ST2 499767200 VALVE GUIDE REMOVER
  
  Fig 3: Removing Valve Guide Using ST2 499767200 Valve Guide Remover
  Courtesy of SUBARU OF AMERICA, INC.
3. Turn the cylinder head upside down and place the ST as shown in Fig 4 .
  Intake side:
  
  ST 499767700 VALVE GUIDE ADJUSTER
  
  Exhaust side:
  
  ST 499767800 VALVE GUIDE ADJUSTER
  
  Fig 4: Installing ST 499767700 Valve Guide Adjuster And ST 499767800 Valve Guide Adjuster
  Courtesy of SUBARU OF AMERICA, INC.
4. Before installing a new valve guide, make sure that neither scratches nor damages exist on the inside surface of the valve guide holes in cylinder head.
5. Put a new valve guide, coated with sufficient oil, in cylinder, and insert the ST1 into valve guide. Press in until the valve guide upper end is flush with the upper surface of ST2.
  ST1 499767200 VALVE GUIDE REMOVER
  
  Intake side:
  
  ST2 499767700 VALVE GUIDE ADJUSTER
  
  Exhaust side:
  
  ST2 499767800 VALVE GUIDE ADJUSTER
  
  Fig 5: Installing ST1 499767200 Valve Guide Remover
  Courtesy of SUBARU OF AMERICA, INC.
6. Check the valve guide protrusion.
  Valve guide protrusion L:
  
  Intake
  
  20.0 - 21.0 mm (0.787 - 0.827 in)
  
  Exhaust
  
  16.5 - 17.5 mm (0.650 - 0.689 in)
  
  Fig 6: Measuring Valve Guide Protrusions
  Courtesy of SUBARU OF AMERICA, INC.
7. Ream the inside of valve guide using ST. Put the reamer in valve guide, and rotate the reamer slowly clockwise while pushing it lightly. Bring the reamer back while rotating it clockwise. After reaming, clean the valve guide to remove chips.
  CAUTION:
  - Apply engine oil to the reamer when reaming.
  - If the inner surface of the valve guide is torn, the edge of the reamer should be slightly ground with an oil stone.
  - If the inner surface of the valve guide becomes lustrous and the reamer does not chip, use a new reamer or remedy the reamer.
  ST 499767400 VALVE GUIDE REAMER
  
  Fig 7: Reaming Surfaces Using ST 499767400 Valve Guide Reamer
  Courtesy of SUBARU OF AMERICA, INC.
8. Recheck the contact condition between valve and valve seat after replacing the valve guide.