MG Magnette KA Instruction Manual page 61

OIL
PAPER RELEASE
PUMP BODY
D I F F E R E N T
LENGTH BOLTS
IDLER
G E A R
CUP
Illustration 44. The components o f t h e o i l pump, which is o f t h e gear type. The gear o n t h e
pump spindle engages w i t h t h e i d l e r gear.
The principal p a r t o f t h e p u m p t o examine is t h e relief valve, w h i c h consists o f a plunger, spring
and h o l l o w cap nut. W h e n t h e o i l pressure registers a pre-determined l i m i t , t h e s p r i n g is compressed
and allows t h e plunger t o uncover a passage which w i l l cause t h e pressure o f t h e pump t o drop.
There i s n o adjustment t o t h e a m o u n t o f pressure ; this is determined at t h e Factory, and isgoverned
by a spring.
The pump i s o f the gear type, fitted w i t h a cover-plate and having a by-pass
relief valve incorporated in the body o f the pump. The relief valve, as can be seen
in Illustration N o .
44,
consists o f a cover which encloses a spring and maintains the
small piston up against a seating in the pump body until such t i m e as either t h e
force o f the o i l through pressure o r non-fluidity i n cold weather forces the piston off
i t s seating. The release o f excess o i l w i l l maintain t h e o i l pressure at a point pre-
determined by t h e makers, dependent upon the resistance o f t h e spring.
It
is
obviously possible t o increase t h e tension o f t h e spring by introducing washers in
the cap, o r obtaining a stronger spring, b u t no such alterations should be effected
w i t h o u t first obtaining t h e advice f r o m the Works.
Illustration 45.-View o f t h e i n t e r i o r o f t h e sump, showing h o w it is
baffled t o prevent surging.
T h e suction f i l t e r is shown in position. If ever
this is removed, be careful t o see t h a t it is screwed u p t i g h t l y against t h e f i b r e
washer a t t h e front.
It is fatal t o get an air leak.
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