MG MGB User Manual

A
THE
ENGINE
A
B
C
K
_
H
N
/|
z
I
.
'
31
I
E13:
l]
H%
I} '.
'
J
‘.
_
i
|
'
'
i
l
l
l
G
l
M
F
'1
'-
00657
Fig.
A.34
Valve
seat
machining
dimensions
Exhaust
(A)
Inlet
(B)
C. 1.437
to
1.438 in.
K.
1.592
to
1.593 in.
(36.50
to
36.53
mm.).
_
(40.43
to
40.46
mm.).
D.
.186
to..188 in.
D.
.186
to
.188 in.
(4.72
to
4.77
mm.).
(4.72
to
4.77
mm.).
B.
Maximum
radius
.015 in.
E.
Maximum
radius
.015 in.
(.38
mm.)
(.38
mm.).
F.
1.33
to
1.35
in.
L. 1.552
to
1.572
in.
(33.78
to
34.29
mm.).
(39.42
to
39.93
mm.).
G.
1.218
to
1.228 in.
M.
1-427
to
1.447
in.
(30.94
to
31.19
mm.).
(36.25
to
36.75
mm.).
H. Throat
diameter
1.146
to
N.
Throat
diameter
1.302
to
1.166
in.
(29.11
to
1.322
in.
(33.07
to
29.62
mm.).
33.58
mm.).
1.
45°.
1. 45°.
J.
Blend
from
seating
to
J.
Blend from
seating
to
throat
diameter.
throat
diameter.
Section A.30
VALVE
SEAT
INSERTS
Valve
seats
that
cannot
be
restored
to
their
original standard
by
normal
cutting
and refacing
should
have
valve
seat
inserts
■tted.
To ■t
an
insert,
machine the
cylinder
head
to
the
dimensions
given
(see
Fig.
A.34).
Press
in
the
insert, which
will be
an
interference
■t of
.0025
to
.0045
in. (.06
to
.11
mm.).
Grind
or
machine
the
seats
to
the
dimensions
given.
Normal
valve ‘grinding-in’
may
also
be
necessary
to
ensure
efficient
valve
seating.
‘ '‘
'
I
'Huuunrw“
“'.
‘”
,
ornc
olo
5
Fig.
A.35
The
tinting
indicator
above the
pulley.
The
groove
is
at
15°B.T.D.C.
for
pistons
No.
1
and 4
2
Fig.
A.36
The
relationship
of
the timing
groove
to
the
crankshaft
pulley
keyway
1.
Position when
indicator
is
above
pulley.
2.
Position
when
indicator
is
below
pulley.
Section
A.31
IGNITION
TIMING
INDICATOR
The
ignition
timing
indicator
is
positioned above
the
crankshaft
pulley
on
later
engines
(see
Fig. A.35).
When changing
a
crankshaft
pulley
or
front
cover ensure
that
the
timing
groove
on
the
new
pulley
is
correct
for
the
timing
indicator
position.
To modify
a
pulley,
make
a saw
cut
relative
to
the
keyway
and
obliterate
the
old
groove
(see
Fig. A.36).
3Nc959
.
Fig.
A.37
Rocker
shaft
assembly
showing
shims
below
the
two
centre
brackets
MGB.
Issue
2.
87518

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English