WÄRTSILÄ Vasa R22, Instruction Manual

Page: 254 / 297

21.2.2 Maintenance
Normally, the main starting valve requires little maintenance. In
case it is to be opened for inspection:
1 Remove the valve from the engine by loosening the
starting air pipe, the pipe from the valve to the start blocking
valve and the bracket with the starting lever. On V-engines,
also remove the pressure gauge pipes from the instrument
panel and, as a unit, the instrument panel and the bracket with
starting lever. The valve can now be removed from the end
cover.
2 Open the plug (10), Fig 21-2, for inspection. Clean the
sealing piston (11) and the seat. Do not use hard tools.
3 Check the pin (3) and the servo piston (6) for free move-
ment. The servo piston is removed by undoing the two hexagon
socket head screws by which the cylinder is fixed. Replace the
O-rings, if necessary.
4 Lubricate the details before reassembling. Fill the servo
piston lubricating grooves with Molykote Paste G.
5 When installing,
check that the O-rings are undamaged
and in position.
Lubricate the contact faces of the lever arm with Molykote.
The solenoid valve (8), Fig 21-1, requires, in principle, no main-
tenance. If the coil has broken, e.g. because of overvoltage, replace
the coil by a new one. If the valve is probable to be clogged by dirt
it can be dismantled for cleaning if caution is observed. Check that
the sealing surfaces are not damaged. Reinstall all details in
correct position and order. If further troubles, replace the valve
by a new one.
21.3 Starting air distributor
21.3.1 Description
The starting air distributor is of the piston type. The distributor
pistons are guided by a cam (19), Fig 21-1, at the camshaft end.
When the main starting valve opens, the guiding pistons (17) are
pressed against the cam, whereby the guiding piston of the engine
cylinder which is in starting position admits control air to the
control piston (22) of the starting valve. The starting valve opens
and allows pressure air to pass into the engine cylinder. The
procedure will be repeated as long as the main starting valve is
open or until the engine speed is so high that the engine fires.
After the main starting valve has closed, the pressure drops
quickly and the springs (18) lift the pistons off the cam, which
means that the pistons touch the cam only during the starting
cycle. Thus wear is insignificant.
22-9601 Starting Air System 21
VASA 22 21-3