Mazda RX-7 - Measurement of ∆ F; Rotor Housing (Front and Rear)

ENGINE
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C. Measurement
of
A
F
(a
F
is
the
smallest clearance
between
the
rotor
and the rotor
housing
surface).
(1)
Install
outer
oil
seals
and
springs in
one side
of the
rotor.
This will
prevent
the
rotor
contacting
and
thus
scuffing
the
side housing
as
you
rotate
it for measurement.
(2)
Invert
the rotor
and insert
it in
the rotor
housing.
The
springs
will hold
the oil
seals
in
place.
(3)
Measure a
F with
a feeter
gauge,
as
shown
in
Figure
7.
There
are four measuring
points,
two on each
side,
at
25 mm
above
and below
the
horizontal
centerline.
as shown
in Figure
8.
Figure
I
The
allowable clearance range
for
A
F is
0.40-0.70 mm.
Notes:
a) lf a
F is less
than
0.40
mm,
the rotor
may
contact
the
housing
at high
speed.
b) Mark
F or
R,
for
front
or
reat,
on
the
rotors
after
measuring
for
a
F.
c)
Use care not
to
damage the
interior
surface
of the rotor
housing
with
the feeler
gauge.
Rotor
houslng
(front
and rear).
1.
Checks (to
be
done
before
clean-
ing).
(1)
Trochoid
surface.
a)
Check
the
surface
for
flak-
ing
of
the
chrome
plate
or
dents,
scratches
or
other
imperfections.
b)
Check
for
gas
leakage
or
deposits:
c)
Check
the
traiting
spark
plug
hole
for
cracks,
as
shown
in
Figure
9.
Trailing
plug
hole.
Figure
9
The maximum
allowance for
cracks is
8
mm; if longer
than
that,
replace
the
housing.
(2)
Rotor housing
sides,
front
and
rear.
Check for
any
indications
of
gas
or coolant leakage,
or for
any abnormal
abrasions. lf
any of these conditions
exist,
determine
the cause
before
proceeding.
Cleaning.
(1)
Clean
carbon
or any
other
de-
posits
with
MEK
or
paint
thin-
ner.
(2)
Remove
all scale
and rust trom
the
coolant
passages
and wa-
ter
jackets.
Measurement
of width.
a)
This
measurement
requires
a 50-75 mm
micrometer.
b)
Measure the
width,
or thick-
ness,
of the housing
at
points
A,
B, C and
D as
shown
in
Figure
10. Points
C
and D are each
20 mm
steps, individually
begin-
ning
at
point
B.
Compare
the
dimension
at
point
A
with the
smallest of
the
other
three,
whichever it is.
lf the
difference
is more
than
0.06 mm, the
housing
must
be reolaced.
D.
2.
3.
S"o^
Figure 7
15