MASSEY FERGUSON MF 14 - Page 46

MASSEY-FERGUSON
GROUP
O
-
SECTION
V - PART 3
ENG'NE OVERHAUI.
PROCEDURES
'-._--
.:l
_._ ::1
VALVE
GAP
.010
coLD
OIL RETTIRN
HOLE
VALVB
GUIDB
MAY
BB OVERSIZED
T/3211
VALVE
STBM
AND
SPRING
GUIDB
VALVB
CAP
VALVE LIFTER
GI.IIDB
_
DO
NOT OVERSIZE
Fis.6
VALVES
1.
The correctvalve
gap
is
.010"
when the
engine
is cold.
Rotate
the engine
until
valve
Iifters
are at
the lowest
point.
See Fig.
6.
Do
not
attempt
to
adjust
exhaust
valve
clearance
with
the exhaust lifter
on
the compression re-
Iief
mechanism or
an
inaccurate clearance will
result.
Valve
stem endsmust be
ground
flat whenad-
justing
valve
gap.
An uneven
or
concave end
can cause
abnormal wear to the
valve
train.
2.
The
outside of
the
valve stem
guide
also
guides
the
valve
spring.
A
valve
spring cap is
used
only
on the
bottom
of the spring.
A
pin
through
the
valve
stem
retains
the spring.
SPRING
MIJST
BE SQUARE
REPI,ACE SPRING
a HI'J#J
o*
Fis.8
Use
a step-type
reamer
to enlarge
valve
guides
if worn.
Oversize valves
are
7/32"
larger in diameter
than standard
valves.
The valve
lifter
guide
is not to
be enlarged.
Lifters
with oversize
stems are
not
available.
3. Correct valve
grinding procedures
are
essential to obtain
a
satisfactory
result.
Face
and seat
angles
must be
accurate
and
the
sur-
faces must be smooth.
(Lapping
is
recom-
mended.
)
A lip must be left
on the valve
head
after
re-
facing. See
Fig.
7.
The
valve
without
the
lip
would burn
and
distort
very
rapidly.
Use a
"Vee"
block
and
the
flat side of
a
grindstone
to
grind
for
valve
clearance. The
end
of
the
stem must be fiat
and
true or ab-
normaL wear
will occur.
4.
Valve springs should
be replaced when
an engine is
overhauled. Weak valve
springs
will spoil the best
overhaul
job.
Valve
spring free length
should
be
checked.
See Fig.
B. Comparing one spring
with the
other
can
be
a
quick
check
to notice
any
differ-
ence. If
a
difference
is
noticed, carefully
measure free
lengths
and compression
length
and strength
of
each
spring. Compression
length
on
early
production
machines
should be
1.65"
and
1.55"
on later
production
models.
IruST
BE
FLAT
A\:D
TRUE
!lu
WRONG
45"<
STEilf
OVERSIZE
STEM
DIAI,IETER
SEE
SPECiFICATIONS
FACE
WRONG
STANDARD
STEM
DIAMETBR
SEE SPECI-
FICATiONS
MUST BE
FLAT
AND TRUE
IMPORTANT:
GRIND FLAT TO OBTAIN
CORRECT VALVE
CLEARANCE
Printed in tJ.S.A.
Fis.7