Installation Instructions

1 ENGINE
(2) Oil Pump
(A) (8) (e) (D)
6000
0087F019
(1) Inlet
(2) Outlet
(3) Inner Rotor
(4) Outer Rotor
(3) Relief Valve
2
81700·82100·82400 WSM,11770
The oil pump in this engine is atrochoid pump.
Inside the pump body, the
10 lobe inner rotor (3) is
eccentrically engaged with the 11 lobe outer rotor
(4). The inner rotor is driven by the crankshaft, which
in turn rotate the outer rotor.
When the inner rotor rotates, the outer rotor also
rotates in the
same direction.
The two rotors have differences in lobe number
and center, which generates
space between lobes as
shown in the figure.
At position (A), there is little space between lobes
in the
inlet port. As the rotor rotates towards
position (8), the space between the lobes becomes
larger, creating a negative
pressure which sucks in
oil.
Outside the inlet port,
as shown in position (C), the
space between the lobes becomes gradually smaller,
and oil pressure increases.
At position (D), oil is
discharged from the outlet port.
The relief valve prevents the damage of the
lubricating system due to high oil pressure. This relief
valve
is a ball type direct acting relief valve, and is
best suited for low pressures.
When oil pressure exceeds the upper limit, the ball
(2) is pushed back by the pressure oil and the oil
escapes.
0087F020
(1) Spring
(2) Ball
1-M8
(3) Valve Seat