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.

Valve seat width W: 

Standard: Intake (A) 0.8 - 1.4 mm (0.03 - 0.055 in) 

Exhaust (B) 1.2 - 1.8 mm (0.047 - 0.071 in) 

Fig 1: Inspecting Intake And Exhaust Valve Seats

Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Correcting Contact Surfaces With Valve Seat Cutter

Courtesy of SUBARU OF AMERICA, INC.