Man D 2840 LE 301 Repair Manual page 108

Installing valve seat insert
Fig. 4
Cool new valve seat insert down to approx. -200°C
and insert it into the cylinder head (at an ambient
temperature of approx. 20°C).
Carry out check by driving it in until the stop is
reached using pressing tool.
Install valve guides.
Note:
When the valve seat inserts have been
changed, the valve seats must be re-
worked.
Note:
D After temperature equalization, machine valve seats
D After machining, clean cylinder head and check for leaks using leak testing device
D f the cylinder head is excessively heated (above +200_C, +390_F) the core hole covers (end
covers) loose their tightness and must be exchanged
D To do this, clean core holes, blow out channels and press in new core hole covers with
"LOCTITE 648" and pressing mandrel
Replacing valve seat insert
4
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