Bukh DV36/48, Workshop Manual

Page: 38 / 196

009W2329-R01
C18
Grinding of valves
1. Place the cylinder head with the valve seats upwards. Block the cylinder head so that
the valves fit tightly against the seats and can be turned freely by means of a rubber
suction disc or the like.
2. Apply abrasive compound to valve and seat, after w hich grinding can tak e place.
3. When grinding, turn the valve by means of the rubber suction disc in various directions
while fitting it at the same time with an equal pressure against the seat. When
grinding, lift frequently the valve and spread all over the seat the abrasive c ompound
applied.
4. You can c heck whether the valve is ti ght by cleaning off the abrasive compound
carefully by for exam ple cleaning liquid. Then make 4 pencil m arks staggered 90
degrees from each ot her on the c ontact face of the valve. Insert the valv e and turn it
about 20 degrees. If the valve is tigh t, the marks will have disappeared.
5. Before refitment in the cylinder head, cl ean the valve carefully for abrasive compound
and apply a thin coat of oil to it. Do the same with regard to the valve seat.
Measures for new valves
Valve stem diameter ................................................... ø9
-0.050 / -0.062
Valve guide bore ......................................................... ø9 – H7
Clearance between valve stem and valve guide ......... 0.050 – 0.077 mm
The valve stems have been specially treated and therefore they must not be ground.