Man D 2842 LE 620 Repair Manual page 97

Installing valve seat insert
Fig. 4
Chill the new valve seat insert down to approx.
−200°C and insert in the cylinder head (approx.
20°C room temperature).
Carry out a check by driving it in as far as it will go
using a pressing tool.
Install the valve guides.
Note:
When the valve seat inserts are replaced,
the valve seats must also be refaced.
Note:
D After temperature compensation: machine the valve seats
D After machining: clean the cylinder head and check for leaks with a leak testing device
D If the cylinder head is excessively heated (above +200°C), the core hole covers (end covers)
lose their tightness and must be replaced
D To do this, clean the core holes, blow out the channels and press in new core hold covers with
"LOCTITE 648" and press−in mandrel
Replacing valve seat insert
4
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