Valve Guide

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

   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) 

2. If the clearance between valve guide and valve stem exceeds the standard, replace the valve guide or valve itself, whichever shows the greater amount of wear or damage. 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 

5.955 - 5.970 mm (0.2344 - 0.2350 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 fit the holes in ST1.
2. Insert the ST2 into valve guide and press it down to remove the valve guide.

   ST1 498267600 CYLINDER HEAD TABLE

   ST2 499767200 VALVE GUIDE REMOVER

   Fig 1: Identifying Cylinder Head Table And Valve Guide Remover

   Courtesy of SUBARU OF AMERICA, INC.
3. Turn the cylinder head upside down and place the ST as shown in the figure.

   ST 18251AA020 VALVE GUIDE ADJUSTER

   Fig 2: Identifying 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 inner surface of valve guide holes in cylinder head.
5. Coat a new valve guide with sufficient oil, put it into the cylinder head, and insert the ST1 into the valve guide. Press in until the valve guide upper end is flush with the upper surface of ST2.

   ST1 499767200 VALVE GUIDE REMOVER

   ST2 18251AA020 VALVE GUIDE ADJUSTER

   Fig 3: Identifying Valve Guide Remover And Valve Guide Adjuster

   Courtesy of SUBARU OF AMERICA, INC.
6. Check the valve guide protrusion amount "L".

   Valve guide protrusion amount L: 

   15.8 - 16.2 mm (0.622 - 0.638 in) 

   Fig 4: Checking Valve Guide Protrusion Amount L

   Courtesy of SUBARU OF AMERICA, INC.
7. Ream the inside of valve guide 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.
   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 499767400 VALVE GUIDE REAMER

   Fig 5: Identifying Valve Guide Reamer (ST 499767400)

   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.