Machining valves and seats     S14

Valve must be replaced if the thickness of  B is less than :

Intake  0.50mm  (0.020")
Exhaust 0.95mm ( 0.037")

Valve must be replaced if, after machining, dimension D is less than :

Intake  36.9mm (1.453")
Exhaust 31.9mm (1.256")

After machining the Valve seat angle of 45°,  machine the 60 and 35 degree angles to achieve a dimension E of :

Intake 36.6mm (1.441")
Exhaust 31.4mm ( 1.236")

and an F dimension of :

Intake 1.2mm (0.047")
Exhaust 1.4mm (0.055")

E30 M3 Repair Manual V2.7.  Copyright ©1999-2001 Koala Motorsport & Brett Anderson