Valve Spring

Check the valve spring for damage and deformation.
Using a caliper gauge, valve spring tester, surface plate and try square, check the valve spring free length, tension/spring height and squareness. If it is not within the standard, replace the valve spring.
NOTE:
- Measurement should be performed at a temperature of 20°C (68°F).
- To check the squareness of the valve spring, stand the valve spring on a surface plate and check its deflection at the top of the valve spring using a try square.
  
  Fig 1: Checking Squareness Of Valve Spring
  Courtesy of SUBARU OF AMERICA, INC.
Valve spring free length:

Standard

41.06 mm (1.617 in)

Valve spring tension/spring height:

Set

Standard

182 - 210 N (18.56 - 21.41 kgf, 40.92 - 47.22 lbf)/33.0 mm (1.299 in)

Lift

Standard

552 - 610 N (56.29 - 62.20 kgf, 124.11 - 137.15 lbf)/22.0 mm (0.866 in)

Valve spring squareness:

Standard

2.5°, 1.8 mm (0.071 in) or less