Bentley R Type - Crankshaft and Connecting Rods; Relief Valves

ENcrNr
Lunnlceuon
SYsmu.
4r
Re-assemble
the
canister and
replace
in
bowl;
ensure that
the
rubber
washer
is
in
good condition.
Ititt
bowl
with
oil
and
replace
in
position.
Replace
wiring
clip
and
re-adjust
dynamo
belt.
On
next
running
the engine,
it
should
be
inspected
for oil
leaks
around the
filter
joint.
Grankshaft
and
Gonnecting
Rods.
The
filtered oil
is
conveyed
to the
relief
valves,
from
where
the
main
oil
supply,
controlled
lt approximately
z$
lbs.
per
square
inch,
.is
delivereaio
ine
main
oil
gallery incorporated
in the
crankcase
casting.
From there
it
is
fed
through
oilways
drilled
in the
crankcase
webs
to
each of the seven
crankshaft
main
bearings,
which
are
of
the
copper-
lead-indium
lined steel
shell
type.
The crankshaft
journals
and
crankpins
are
bored
for lightless
and
to act
as
oil
conduits,
the ends
of
the
holes
being
plugged with
steel
caps.
A11 the
main
bearings
have
circumferential
oil
grooves,
and
radial
holes are drilled
in the crank
journals
to
register with
these
grooves.
OiI
from the
main
bearings
passes to
the
bore
of each
journal
through the
radial transfer
holes
in the
crankshaft
and
then
to the
cranklins
through diagonal
ducts
drilled
in
the
crankshaft
webs,
and
so
thiough
radial
holcs to
each
crankpin
big-end
bearing,
these
bearings
-being
of a similar
type
and
material
to
that
of
the main
bearings.
Each connecting
rod
is
drilled
to
convey
oil
to the
gudgeon
pin
bearing,
the drilling
passing
through
the
big-end
bearing
shell.
Small
holes Jre
cross-drilled
into-this
oilway to
allow a
fine squirt
of
oil
to
lubricate the cylinder walls.
Two
radial holes in
the crankpin
ensure
communication,
twice
per
revolution, with
the oilway
up the
connecting
rod.
Thus,
all the
crank-
shaft
and
connecting
rod bearings
are supplied
with
oil
under
pressure.
Relief
Valves,
The
double
relief valve
unit
is
mounted
on
the
right-hand
side of
the crankcase.
(See Fig. 9.)
The two
valves are in
series,
and their
combined effect
is to
regulate
the
pressure
of the main
high-pressure
supply
to the crank-
shaft
and
connecting rod bearings to
approximately
zJ
lbs.
per
square
inch.
Oil
passing
the
high-pressure valve
(2,
Fig. 9) enters-
the
low-
pressure
chamber
and Jrom
there via
a
pipe
(a)
to
the inlet
rocker
shaft.
In
order
to
ensure a
supply
of oil
to the
low-pressure
system
under
all conditions
of
running,-small
slots
are cut
in
the'seating
of
the high-pressure
valve
(2).