Valve Seat Ring
Repair / Checking
A5.05. 01.08.02.01
M20
en / 30.09.2010 IB023062 3/5
01
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)
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).
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.
CAUTION
Handle the cutter head (2) with care, cutters are sensitive to impact, hard touch-down
can also damage the valve seat face.
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