4-Engine
TORQUE WRENCH SETTINGS
Crankcase nuts
...................
.
Crankcase bolts and nuts
............
.
Cylinder head nuts
................
.
Rocker shaft nuts
.................
.
Flywheel gland
nut
................
.
Connecting rod bolts and nuts
........
.
Generator pulley nut
...............
.
Fan
nut
.......................
.
Engine carrier nuts
................
.
Clutch to flywheel . . . . . . . . . . . . . . . . .
25
ft/lb
14
ft/lb
23
ft/lb
16
ft/lb
217 ft/lb
24 ft/lb
45 ft/lb
45 ft/lb
18
ft/lb
18
ft/lb
Oil
drain plug
...................
.
Spark plugs
.....................
.
Exceptions to the above:
On 36
bhp
engine
Crankcase nuts
................
.
Cylinder head nuts
...............
.
Oil drain plug (to August 1959) ·
.....
.
Spar.k piug insert
...............
.
On 53 and 57 bhp engine
Generator pulley
nut
..
:
.........
.
Bolt for fan and crank shaft pulley
25
rt/ib
25
ft/lb
22 ft/lb
27 ft/lb
29 ft/lb
52
ft/lb
32 ft/lb
101
ft/lb
I.
DESCRIPTION
The air cooled, four cylinder, overhead
valve
engine
is
of
the horizontally opposed type·and
is
basically the same
in
all
models.
The crankcase
is
two piece and die-cast
in
light alloy.
As
the two crankcase halves are machined to mate together,
replacement can only be made in pairs.
The cylinders attached to the crankcase are
of
special
cast iron, incorporating fins on the outside surfaces for
cooling purposes.
As
the cylinders are separate, each can
be
replaced or interchanged provided the matching piston
is
fitted to the appropriate cylinder.
A single removable cylinder head
is
fitted to each pair
of
cylinders, the head
is
also cast in light alloy
incorporating fins for cooling purposes. Valve seat inserts
and
valve
guides are shrunk into the head.
The crankshaft is mounted in the crankcase and
supported by four main bearings.
In
earlier models three
of
Engine Assembly.
10
the bearings are
of
split steel backed lead-bronze type, the
fourth bearing is aluminium alloy
of
the bush type;
crankshaft end thrust
is
taken by number two main bearing.
Later models have four light alloy lead coated bearings one
of
which
is
the split type; crankshaft end thrust
is
taken by
number one main bearing. At the. clutch end
of
the
crankshaft an oil seal
is
fitted, with an oil thrower and oil
return thread incorporated on the pulley end
of
the shaft.
The flywheel complete with starter ring gear
is
secured
to
the crankshaft
by
a gland nut and located in position by
four dowel pins. Woodruff keys are used
to
secure the
timing gear and distributor drive gear to the crankshaft.
The four connecting rods are fitted with detachable
lead-bronze shells in the big end bearing end
of
the rod,
with the fully floating gudgeon pin supported in a bronze
bush at the small end
of
the
rod.
The pistons
are
fitted with two compression rings and
