VALVE SEAT Subaru Outback BS

VALVE SEAT

Inspect the intake and exhaust valve seats, and correct the contact surfaces with a valve seat cutter if they are defective or when valve guides are replaced.

Contacting width of valve seat W

Standard

Intake

1.0 mm (0.039 in)

Exhaust

1.5 mm (0.059 in)

Scheme 654

Scheme 655

Scheme 656

Scheme 657

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: 5.500 - 5.512 mm (0.2165 - 0.2170 in) Valve stem outer diameters: Intake 5.455 - 5.470 mm (0.2148 - 0.2154 in) Exhaust 5.445 - 5.460 mm (0.2144 - 0.2150 in) Place the cylinder head on ST1 with the combustion chamber upward so that valve guides fit the holes in ST1. Insert the ST2 into valve guide and press it down to remove the valve guide. ST1 18250AA010 CYLINDER HEAD TABLE ST2 499765700 VALVE GUIDE REMOVER Turn the cylinder head upside down and place the ST as shown in the figure. ST 18251AA050 VALVE GUIDE ADJUSTER (INTAKE SIDE) ST 18251AA060 VALVE GUIDE ADJUSTER (EXHAUST SIDE) 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. Put a new valve guide, coated with sufficient oil, in the cylinder head, and insert the ST1 into valve guide. Press in until the valve guide upper end is flush with the upper surface of ST2. ST1 499765700 VALVE GUIDE REMOVER ST2 18251AA050 VALVE GUIDE ADJUSTER (INTAKE SIDE) ST2 18251AA060 VALVE GUIDE ADJUSTER (EXHAUST SIDE) Check the valve guide protrusion amount "L". Valve guide protrusion amount L: Intake 8.6 - 9.0 mm (0.3386 - 0.3543 in) Exhaust 10.7 - 11.1 mm (0.4213 - 0.4370 in) 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. ST 499765900 VALVE GUIDE REAMER 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. After reaming, clean the valve guide to remove chips. Recheck the contact condition between valve and valve seat after replacing the valve guide.

Scheme 658

1. Check the flange and stem of the valve, and replace the valve with new one if damaged, worn, or deformed, "H" exceeds the standard, or if there is uneven wear. Head edge thickness H: Standard Intake (A) 1.0 mm (0.039 in) Exhaust (B) 1.2 mm (0.047 in)
2. Put a small amount of grinding compound on the valve seat surface, and lap the valve and valve seat surface. Install a new valve oil seal after lapping. NOTE: It is possible to differentiate between the intake valve and the exhaust valve by their overall length. Valve overall length: Intake 103.5 mm (4.075 in) Exhaust 103.2 mm (4.063 in)

Scheme 659

1. Check the valve springs for damage, free length, and tension. Replace the valve spring if it is not within the standard value presented in the table.
2. To measure the squareness of the valve spring, stand the valve spring on a surface plate and measure its deflection at the top of the spring using a try square. Free length mm (in) 49.06 (1.9315) Tension/spring height N (kgf, lb)/mm (in) Set 182 - 210 (18.6 - 21.4, 40.9 - 47.2)/31.0 (1.220 in) Lift 316 - 350 (32.2 - 35.7, 71.0 - 78.7)/21.0 (0.827 in) Squareness 2.5°, 2.1 mm (0.083 in) or less

Scheme 660

1. For the following, replace the oil seal with a new part. When the lip is damaged. When the spring is out of the specified position. When readjusting the surfaces of valve and valve seat. When replacing the valve guide.
2. Set the cylinder head on ST1.
3. Using the ST2, press in the oil seal. ST1 18250AA010 CYLINDER HEAD TABLE ST2 18261AA010 VALVE OIL SEAL GUIDE NOTE: Apply engine oil to oil seal before press-fitting. When press-fitting the oil seal, do not use a hammer to strike in.

Scheme 661

Scheme 662

1. Check the valve lifter visually.
2. Measure the outer diameter of valve lifter. Outer diameter of valve lifter: 32.959 - 32.975 mm (1.2976 - 1.2982 in)
3. Measure the inner diameter of valve lifter mating surface on cylinder head. Inner diameter of valve lifter mating surface: 32.994 - 33.016 mm (1.2990 - 1.2998 in)
4. Check the clearance between valve lifter and valve lifter mating surface. The clearance can be checked by measuring the outer diameter of valve lifter and the inner diameter of valve lifter. If it exceeds the standard or offset wear occurs, replace the cylinder head. Valve lifter and valve lifter mating surface clearance: Standard 0.019 - 0.057 mm (0.0007 - 0.0022 in)