Operator`s manual

INTRODUCTION
SERVICE
TABLE
OF LIMITS
This
Table of
Limits is
provided
to serve
as a guide
to all service
and
maintenance
personnel
engaged
in
the
repair
and overhaul
of Textron
Lycoming
Aircraft
Engines.
Much
of the
material
herein
contained
is
subject
to revi-
sion;
therefore,
if any
doubt
exists regarding
a specific
limit
or the incorporation
of limits
shown,
an
inquiry
should
be addressed
to
the Textron
Lycoming
factory
for
clarification.
DEFINITIONS:
Ref. (1st column)
Ref. (2nd column)
Chart
(3rd column)
Nomenclature
(4th column)
Dimensions
(5th
& 6th columns)
Clearance
(7th
& 8th columns)
The
numbers
in the first
column headed
"Ref."
are shown
as a reference
number
to locate
the area
described
in the "Nomenclature"
column.
This number
will be
found
in a
diagram
at the end
of each
section
indicating
a typical
section
where
the limit
is applicable.
Indicates
the
old reference
number.
There
are
no diagrams
in this
manual
for
these
numbers.
These numbers
are only
to be
found in previous
publications.
The
letter or
letter and
number in
this column
are used
as symbols
to designate
engine
models
to
which the
specific
limits
is applicable.
A
list of
the letter
or
letter
and number
and
the engine
to which
they refer
is shown
below.
This
is a brief
description
of
the parts
or fits
specified
in the
adjacent
columns
and indicated
in the
diagram
at end
of each
section.
The dimensions
shown
in column
5 are
the minimum
and
maximum
dimensions
for
the part as
manufactured.
The dimensions
shown in column
6 indicate
the
limit
that must
not be exceeded.
Unless
it can be
restored to
serviceable
size, any
part that
exceeds
this dimension
must
not be rebuilt
into
an engine.
Like the dimensions
shown in the
5th and 6th
columns,
the clearance
represents
the fit
between
the two
mating
surfaces
as controlled
during
manufacture
and as
a limit
for permissible
wear.
Clearances
may
sometimes
be found
to
disagree
with limits
for mating
parts;
for example,
maximum
diameter
of cylinder
minus
minimum
diameter
of
piston exceeds
limit for
piston and
barrel clearance.
In
such
instances, the specified
maximum
clearance
must not be exceeded.
In some
instances,
where
a parts
revision
has caused
a dimensional
or tolerance
change,
the
superseded
dimenional
data
has
been
deleted
from the
list; provided
compliance
with the
change
is not mandatory.
Letters
of the alphabet
and
numbers
are used
as symbols
throughout
the
Table
of Limits
to represent
specific
interpretations
and to designate
engine
models.
Letters
in parenthesis
refer
to dimensional
characteristics;
letters
(or
combinations
of letters
and
numbers)
without parenthesis
indicate engine
models.
They are
listed below
with
their separate
definitions.
(A)
These fits
are either shrink fits controlled
by machining, fits
that may readily be
adjusted,
or fits
where wear
does not normally
occur.
In each
case, the
fit must
be held to
manufacturing
tolerance.
(B) Side clearance
on piston rings must be measured with
face of ring flush with
piston.
(D)
The dimensions shown
are measured at the bottom
of the piston skirt
at right
angles
to the
piston pin.
(E)
Permissible wear
of the crankshaft (rod
and main bearing journals)
to be minus
0.0015
on the diameter.
(L)
Loose fit; wherein
a definite
clearance is mentioned
between
the mating
surfaces.
(T)
Tight fit; shrink or interference
fit.
(WD)
Wide
Deck Crankcase.
i