SELVA MARINE Blue Whale 250 EFI Service Manual page 36

GEN
INFO
Rotor vane operation
The variable camshaft timing unit consists of a rotor vane and rotor vane housing. The rotor vane is
fastened to the intake camshaft with a bolt, which allows them to rotate together. The rotor vane
housing is fastened to the driven sprocket of the intake camshaft with a bolt, which allows them to
rotate together.
The rotor vane in the rotor vane housing is operated by the engine oil pressure to advance or retard
the camshaft. When the engine is started, the engine oil pressure is low and the rotor vane is fixed
to the housing by a lock pin. After the engine is started, the engine oil pressure increases as the
engine speed increases and the engine oil enters the advance chamber in the housing and the lock
pin is released. When the camshaft advances, the engine oil that entered the advance chamber in
the housing moves the rotor vane to the advance direction, and the engine oil in the retard chamber
passes through the spool valve and returns to the oil pan. When the camshaft retards, the engine oil
enters the retard chamber in the housing and moves the rotor vane to the retard direction, and the
engine oil in the advance chamber passes through the spool valve and returns to the oil pan.
1 Rotor vane
2 Rotor vane housing
3 Bolt
4 Retard passage
5 Drive sprocket (IN)
6 Camshaft
7 Advance port
8 Retard port
1-31
General information
B
A
0
1
9
D
0
1
C
È
2
7
8
2
3
4
5
6
9 Advance chamber
0 Lock pin
A Seal
B Retard chamber
C Advance passage
D Spring
È Rotation direction of variable camshaft timing
S6P21115
6P23H11