Man D 2840 LE 301, Repair Manual

Page: 108 / 194

4
Replacing valve seat insert
106
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