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 the outside diameter of valve stem and the inside diameter of valve guide with outside and inside micrometers respectively.
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)

Limit

0.15 mm (0.0059 in)

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

Fig 2: Measuring Outer Diameter Of Valve Stem With Micrometer
Courtesy of SUBARU OF AMERICA, INC.
If the clearance between valve guide and stem exceeds the limit, replace valve guide or valve itself whichever shows greater amount of wear. See 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 cylinder head on ST1 with the combustion chamber upward so that valve guides enter the holes in ST1.
2. Insert ST2 into valve guide and press it down to remove valve guide.
  ST1 498267800 CYLINDER HEAD TABLE
  
  ST2 499767200 VALVE GUIDE REMOVER
  
  Fig 3: Inserting ST2 Into Valve Guide Using Valve Guide Remover ST2 (499767200)
  Courtesy of SUBARU OF AMERICA, INC.
3. Turn cylinder head upside down and place ST as shown in the figure.
  Intake side: ST 499767700 VALVE GUIDE ADJUSTER
  
  Exhaust side: ST 499767800 VALVE GUIDE ADJUSTER
  
  Fig 4: Turning Cylinder Head Upside Down
  Courtesy of SUBARU OF AMERICA, INC.
4. Before installing 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 new valve guide, coated with sufficient oil, in cylinder, and insert 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: Inserting ST1 Into Valve Guide Using Valve Guide Remover ST1 (499767200)
  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: Identifying Valve Guide
  Courtesy of SUBARU OF AMERICA, INC.
7. Ream the inside of valve guide with ST. Slowly rotate the reamer clockwise while pressing it lightly into valve guide, and return it also rotating clockwise. After reaming, clean 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 chips, use a new reamer or remedy the reamer.
  ST 499767400 VALVE GUIDE REAMER
  
  Fig 7: Reaming Inside Of Valve Guide Using ST
  Courtesy of SUBARU OF AMERICA, INC.
8. Recheck the contact condition between valve and valve seat after replacing valve guide.