Mazda RX-7 - Rotor; Rotor Bearing

ENGINE
-+-
I
Figure
10
Note:
The
measuring
Point
for
the
micrometer
is
on
the
inner
side
of the
rubber
seal
groove.
After
measuring,
mark
the
housing
F or R
to denote
the
front and
rear sides.
Rotor.
1. Checks
(to
be
done before
clean'
ing).
(1)
Rotor
condition.
Check
for
gas
leakage,
anY
damage
to the
rotor, and
the
state
of combustion.
FinallY,
check
for any
marks
that
would
indicate
the
rotor
had been
contacting
the
side
of
the
housing;
these
marks
maY be
found,
in
particular,
in the area
of
the
tip of
the
rotor.
(2)
Internal
gear.
Check
caref ully
for cracks,
ex-
treme
abrasions,
dents,
nicks
and scratches
and
other
dam'
age
to
the
gear
and
teeth.
(Cracks
will sometimes
aP-
pear
around
the sPring
Pin
hole and
in the sPring
Pin
it'
self
.)
2.
Cleaning.
When
cleaning
the
rotor, do
not
use
a stone,
sandPaPer,
anY
tool
or abrasives
to
remove
carbon
from
the apex
seal
groove.
This
Figure
11
groove
should
be
cleaned
onlY
with a brush
and
kerosene
or MEK.
3.
Measurements.
(1)
Using
a 50-75
mm
micrometer,
measure
the rotor
at the
three
points
shown
in Figure
11.
(2)
Calculate
a
R by
the
follow'
ing formula:
A
R
=
(Rotor
housing
width
at
point
A)
-
(Max.
rotor
width
at any
point
measured
in
this
step)
The allowable
range
of
a
R is
0.13-0.17
mm.
(3)
Measurement
of
a
H.
This measurement
requires a
straightedge
and a
set
of feel'
er
gauges.
Check
it
as shown
in Figure
12.
The allowable
range of
a
H
is
0.15-0.20
mm.
Figure
12
F. Rotor
bearing.
1. Checks.
Look
for abnormal
abrasions
or
any signs
of
f
laking
or
seizing.
2.
Measurements.
('l)
Measure
the bearing
with
the
following
Procedure:
a)
Use an
inside
micrometer
and
measure the
bearing at
the six
(6)
positions
shown
in Figures
13
and
14.
E.
Figure
13
16