Triumph TR4A - Fuel Octane Requirement; Steering Unit

ROUTINE
SERVICING
Stee
ng Utrit
(Fig.
38)
Remove
a sealing plug
from
the
toP of
the stee
ng unit
and
replace
it by
a grease
nipple.
APPIy
the grease
gun
and
give
5 strokes
only.
Remove
the
nipple
and refit
the
Plug
Over
greasing
can
cause
damage
to
the rubber
bellows.
Water PumP
(Fig.
39)
Apply
a grease
gun
to
the
$ease
niPPle
and
inject grease
until
it exudes
from a
hole
in the side
of
the pumP'
FUEL
OCTANE
REQT'IREMENT
Fuel octane
requirements
arerelated
to comPresslon
Pressur
thus the
higher
the compression
ratio, the
higher
the fuel
octa
requirement
for maximum
oPerating
emciency.
The
fuel octa
requirement
(research
method)
for
the TR4A
is as follows
9
: 1 compression
ratio
Research
Octane
Number
97
miniml
Fuels
commercially
available
are
generally
-designated
Mixture,
Premium
and
Super,
the
octane
ratings of
which
vr
between
Oil Companies
and
between
countries,
In genel
however,
the
octane
rating
corresponds
as follows:-
Premium
Research
Octane
Number
9'1 to 99
Super
..
Research
Octane
Number
l0l
Detonation
resulting
from
the use
of fuels
of a
lower oct
rating
than specified
will,
if allowed
to continue,
cause
serr
damage
to
an engine.
Therefore,
if a
suitable
high octane:
is not available,
the
ignition
setting
must
be retarded
temPom
to suit.
(Se€
"Ignition", page
41).