11 12 527 

(cylinder head dismantled)

Reworking one valve seat on engine BMW M73

Machine valve seat surface with special tool 00 3 520 or 00 3 580 in accordance with tool manufacturer’s instructions.

Reworking one valve seat on engine BMW M73

Note:

After machining the outer and inner diameters of the valve seat face with a correction milling tool, rework to the specified diameter until the correct valve seat width (5) is obtained.

  1. Valve-seat angle
  2. Correction angle, external diameter
  3. Correction angle, internal diameter
  4. Outside ∅ of the seat face
  5. Valve seat width

Specified values (1 to 5), refer to Technical Data:

Valve seat angle ° 45
Correction angle outside ° 15
Correction angle inside ° 60
Valve seat width (dimension “B”)
Intake mm 1.65 ± 0.25
Exhaust mm 2.00 ± 0.25
Valve seat diameter
Intake outside diameter mm 41.5
Exhaust valve Ø 35

Outer Ø

mm 34.6
Exhaust valve Ø 36

Outer Ø

mm 35.6