Hatz 2-4L30 Workshop Manual page 83

– Insert valves into valve guide.
Lap the valve cones with grinding paste
(grade: 180-250).
Note:
To check the lapped valve seats, clean the
valves, insert them and pour a small
amount of diesel oil into the inlet and ex-
haust ports. No fuel should seep through
the valve seats.
Assembling the cylinder head:
– To assemble the cylinder head, follow
the dismantling instructions in reverse as
appropriate.
Note:
– Engines built in 1979 - 1983 have one
spring per valve; from 1984 onwards,
two springs per valve were installed. If
repair work is carried out in this area,
the second valve spring should be retro-
fitted.
– On M 31/M 40 engines up to 2300 rpm,
cylinder heads with the code letter „H"
(high swirl) are used; above 2300 rpm
the cylinder head code letter is „L" (low
swirl).These code letters are stamped in
the inlet port.
– On engines built from mid-1986 on with
a running speed below 2300 rpm the
longitudinally slotted rocker and valve
stem seal adjusting screws are used;
these screws were installed on all engi-
nes from mid-1989 onwards. Retrofit
these screws if repairs are carried out.
– Before pressing on the valve stem seals,
insert the valves into the valve guides.
Press the seals on with assembly tool
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