Valve Seat Ring
Repair / Checking
A5.05. 01.08.02.01
M20
en / 15.03.2001 IB023062 3/5
01
Ĺ
1.1 The valve seat rings are reusable without refinishing when
•the circumference of valve face is metallic bright
•no carbon deposits with blow holes or visible wear are present
•by inspecting cracks using an illuminated magnifying glass (8-fold magnification) or
powder spraying procedure (Met L'Check) and/or in the flux procedure no crack
formation is established at the valve face.
1.2 The valve seat rings are not reusable when
•cracks are present in the seat face
•burn holes are present
•the refinishing limits have been exceeded.
2. Cleaning
Remove the residues from the seat faces.
3. Maintenance (refinishing the valve seat rings)
Note:
Refinishing is to be carried out with the MaK precision seat grinding machine (W1) in a
workmanlike manner. Refer to special operating instructions.
Alternatively the seats may be refinished by means of the MaK valve seat milling device
(Fig. 6/W2). Unnecessary stock removal is to be avoided, only carbon pockets are to be
repaired if they are present in the contact area.
3.1 Remilling of the valve seat
3.1.1 Clean the valve seat ring thoroughly in the contact area (3) of the centering washer (4) in
order to ensure an absolutely centrical fixing of the guide mandrel (5). Remove O-ring from
guide bush.
3.1.2 Insert centering washer (4) with guide mandrel (5) and tighten with tension nut (6).
Attention:
Handle the cutter head (2) with care, cutters are sensitive to impact, hard touch-down can
also damage the valve seat face.