MAK M 20 - Page 73

Valve Cones
Repair / Checking
A5.05. 01.08.01.00
M20
en / 31.05.2010 IB001351 4/5
01
4. Maintenance (check of contact
reflection/grinding)
4.1 Apply small dots of the diamond paste Dp
30/10 - 15 µm with a syringe to the valve
seat of the new or refinished valve cone
and distribute the paste uniformly (Fig. 4).
Therafter the seat ring surface is to be
sprayed with a thinner (F25) belonging to
the diamond paste, for dilution and in
order to increase of the grip.
4.2 Insert the oiled valve stem into the guide
bush. Fasten the device (Fig. 5/W1) to the
valve head and grind the valve cone face
and seat by hand applying a moderate
pressure, rotating the device. The contact
reflection “a” (Fig. 6/a), visible by the
rough grinding process, should be
30 - 50 % of the circumferential seat
width “b”
starting from the outside diameter.