Man D 2842 LE 620, Repair Manual

Page: 97 / 180

4
Replacing valve seat insert
95
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