Mazda RX-7 User manual

MAZDARX-7
COM
PETITIONPREPARATION
ANDSERVICEMANUAL
@Copyright
1980byToyoKogyo
Co.,
Ltd.

CONTENTS
ENGINE
Basic
Specifications
l. Explanation
and
DescriPtion
of
Competition
Parts
ll. Additional
Required
Parts
lll. Machining
and
Fabrication
Operations
and
Procedures
lV. Checks
and
Measurements
V. Assembly
Operations
Vl. Checks
and
Adjustments
Vll. Operating
Procedures
cHASSTS
DRIVELINE
l. Explanation
and
DescriPtion
of
Competition
Parts
ll. Notes
on
Machining
and
Assembly
lll. Checks,
Adjustments
and
Practices
BRAKE
SYSTEM
Specifications
l. Explanation
and
DescriPtion
of
Competition
Parts
ll. MachiningOPerations
lll. Checks,
Adjustments
and
Maintenance
STEERING
AND
SUSPENSION
Specifications
l. Explanation
andDescriPtion
of
Competition
Parts
ll. Machining
and
Installation
Operations
' lll. Checks,
Adjustments
and
Maintenance
APPENDIX
Comparison
of
Specif
ications,
RX-7
and
5
B
8
13
21
21
24
RX-3 47
27
28
31
35
36
37
39
40
44

PREFACE
Toyo
Kogyo
Co.,Ltd.,
wishes
to extend appreciation
for
your
interestinandefforts
with
theMazda
RX.7
in automobile
competition.
ThisManual
reflectstheknowledge
gained
byMazda
competitors
and
Toyo
Kogyoengineers
through
much
research,devel-
opment
and
actual
competition,
and
is to be
considered
recommended
practice.
lt is
intended
foruse
onlyby
thoseseriously
engaged
intheconstruction
and
maintenance
ofthe
RX-7
in
competition;
the
parts,procedures
and
specifications
outlined
within
the
Manual
are
for
racing
and
competition
use
only,and
specif
ically
haveno
relationtoor
application
orother
purpose
for
street
and
highway-driven
automobiles.
lfthe
informa-
tion
contained
inthisManual
is
applied
toa street
orhighway-driven
RX'7,
the
results
may
include
voidedwarranties,
reduced
reliability,and
losses
in
performance,
economy
and
emissions,
all
orsome
of which
maybeillegal
in certainareas
and
which
are
def
initely
notapproved
by
ToyoKogyo
Co.,Ltd.
With
the parts,
procedures
and specif
ications
in the Manual
the competitor
.can
assemble
and
maintain
theengine,
drivetrain
and
chassis
components
and
the
various
appropriate
subsystems
involvedinacompetition
Mazda
RX-7.
The
individualcompetitor
should
beaware
that
many
ofthe
parts
and
procedures
outlined
in
this
Manual
may
not
beallowed
under
the
rulesand
regulations
ofcertain
competition
organizations,
and
itis
the
responsibility
of thecompetito(,
racer,
mechanic
orother
person
associated
with
racingaMazdato
have
a
fullunderstanding
ofthe
pertinent
rulesand
regulations
ofhis
comp-etition
governing
body.
For
instance,
the
readerwill
notice
there
isno
section
in
this
Manual
on
thedesign
and
construction
ofa
rollcagestructure,
as
thesedetails
and
requ
i
rements
varywithdif
ferentsanct
ioningorgan
izations.
In
competition
there
is
a
highdegree
ofexperimentation,
and
the
reader
is
assumed
to
understand
that
such
experimentation
isonan
individualbasis,
isnotcovered
bythis
Manual,
and
fromthe
position
ofToyo
Kogyo
Co.,
Ltd.,and
its
affiliates,
istherefore
categorized
as non-recommended
practice.
Toyo
Kogyo
Co.,Ltd.
is interested
in the
resufts
of any competition
experimentation
or experience,
but specifically
cannot
recommend
anew
procedure
until
ithas
undergone
athorough
analysis
byappropriate
company
engineering
staf
f.
In
any
formof automobile
competition
theindividual
is also
considered
to assume
responsibility
for
hisorher
actions,
and
to realize
andaccept
thatautomobile
compe'
tition
is,by
its
verynature,
ahazardous
activity
withahigh
degree
of
risk
of
damage
to
equipmen[
and/or
personal
injury.By
the
application
ofthis
Manual
it is
assumed
the
inbividual
willbe
operating
a competition
automobile
atorneartheouter
limitsof its
performance
envelope,
and
theclosertothose
limits
the
greater
the
risk.Neither
Toyo
Kogyo
Co.,
Ltd.,
nor
any
of
their
aff
iliates
oremployees
assume
any
responsibility
inany
manner
forany
losses,
eithrer
to equipment
orpersons,
resulting
from
the
use
of any
Mazda
automobiles
incompetition
ortheapplication
ofany
parts,
procedures
orspeci'
f
ications
outlined
inthis
Manual.
Finally,
automobile
competition
is
aconstantly
changing
area
ofendeavor,
subject
to
new
teihnology,
and
this Manual
is the current
best
recommended
practice
but is
subject
tochange,
without
nctice,atany
time.
Again,
thank
you
for
your
interestintheMazda
RX-7
inautomobile
competition,
and
we
extend
you
good
luckandbest
wishes
in
your
efforts.

Type 12ARotary
Displacement,
per
rotor 573cc
Displacement,total 1146cc
Compression
ratio 9.4:1
lntake
porting Peripheral
Exhaust
porting Peripheral
Carburetion Twinthroat,down
draft
Weber
Lubrication Wetsump
Cooling Liquid
lgnition Transistorized,
capacitivedischarge
(cDr)
Maximumallowable
enginespeed 9.000 RPM
ENGINE
BasicSpecifications
Explanation
and Description
of
CompetitionParts.
A. Housing
group.
1. Rotor
housing,
4352
10'100
It has
the following
differences
fromthe
stock
housing:
(1)
Theintake
porting
is
peripher-
al.
(2)
lt is
sandcast
fromlowervol-
ume
patterns.
(3)
Thecoolant
passages
aredif-
ferent.
(4)
Thetrochoid
surface
is
direct-
lychrome
plated
ontothe
cast-
inginstead
of beinga sheet
metal
insert.
The
intake
andexhaust
as
follows: timingis
2. Side
housings,
front:435210200
intermediate:
435210400
rear:4801
10300
ENGINE
They
differ
from
thestockhous-
ings
intheseways:
(1)
Theintake
ports
are
filledin
solid.
(2)
Theintermediate
housinghas
anoilseparatortank. :
(3)
The
passages
for
the
oil
pump
on
the
front
housing
arelarger
passages.
3. Tensionbolts,4352 10451A
These
arethe stockboltswith
rubberbondedto them which
dampensout
vibrations
atcertain
f
requencies
and prolongsbolt
life.
4. Stationary
gears,
front:4352
10500
rear:435210
550
Comparedto the stock gears,
thesehavethe following
differ-
ences:
(1)
For
strength,thematerial
and
heat
treatmentis
different.
(2)
Amachined
groove
aroundthe
bearing;thisfeatureenhances
bearinglife.
IntakeOpens86'
BTDU
Closes
75'ABDC
Stationary
Gear

ENGINE
Oil
pan,435210
700
This
isan
increased
caPacitY
Pan
to
maintain
pressure
under
racing
conditions,
particularly
while
cor-
nering.
Baffle
plate,
4352
10709
Thisbaffle
plate
will
maintain
an
adequate
oil
supPlY
around
theoil
pump
pickup
while
cornering
or
braking.
Botatlng
grouP.
1. Balancer
assemblY,435211
010
These
pieces
differ
f
rom
stock
bY
being
balanced
toa closer
toler-
ance.
2. Rotor,435211
100
The
competition
rotor
hasthe
fol'
lowing
features:
(1)
The combusion
chamber
is
the Medium DeeP Recess
(MDR)tyPe.
(2)
lt
hasasnap
ringtoretain
the
internal
gear
in
Place.
(3)
The
apex
seal
groove
ischrome
plated
to
reduce
wear.
standard:
10111'l
111
oversize:
1058
78
135
Theoversize
bearing
is available
to provide
thecorrect
oil clear'
ance,
and
is
larger
in
diameter
bY
30p
Apex
seal,4352
11301
Theapex
seal
is made
of carbon
and
is3.0
mmthick.
Apex
seal
spring,4352
11304
This
spring
is designed
sPecifi'
cally
for
the3.0
mmcarbonaPex
Side
seal,
4801
11
311
Compared
to
thestock
seal,
this
side
seal
ismolybdenum
treated
forincreased
wear
resistance.
Corner
seal,
1BB1
78146
The corner
seal has a sPraYed
molybdenum
coating
for
self
lub-
rication
properties.
Outer
oilsealsPring,
front:4352
11
353
rear:43521
1
363
The increased
pressure
of this
spring,
dif
ferent from original,
13kg/cm'as
compared
to
B
kg/cm'
forthe
slandard
oil sealspring,
prohibits
combusion
gasblowbY.
For
the
inneroil seal,
thestock
spri
ngissatisfactory.
Eccentric
shaft,4352
11400
The
material
and
conf
igurationof
this
shaft
are
identical
to stock,
but to reduce
the likelihood
of
bearing
seizure,
the rear
halfof
the
rear
main
journal
ismachined
20p.smaller
in
diameter,
as
shown
in
the
illustration.
(aD = A
- B)
7.
Rotorbearing,
aO
0

ENGINE
10.Drive
pulley,
435211
601
This
pulley
has
the
followingdif-
ferencesfromthestock
version:
(1)
The
materialis
aluminum
alloy
toreduce weightand
rotating
inertia.
(2)
Theoilseallip'scontactarea
has
been
treated
forwearre-
sistance.
(3)
Thediameter
is
90
mm.
11. Flywheel,4352 1
1755
Thisflywheelis fabricatedfrom
steelbut is significantlylighter
thanstock
to reducerotating
in-
ertia.
12. Needle
bearing,082278184
Theneedle
bearing
has
a higher
load
capacitytowithstand
severe
clutchengagements.
C. Intake andexhaust
group.
1. Intake
manifold,
435213100
This
manifoldhas
thefollowing
features:
(1)
ltiscastfromaluminum
alloy.
(2)
lthas
beendesignedtoaccept
and
workwiththeDDW48lDA
carburetor.
andto match
an
engine
installation
angleof
4"40'.
(3)
The
length
of theintake
pas-
sages
has beendetermined
foroptimumtuningandeffi-
ciencyat
the
designedengine
speeds.
2. Gaskets,
rotorhousing
to
intake
manifold:
086278205
intakemanifoldto
carburetor:
. 086278206
3. Carburetorsupport,0862
78240
This
support
reducesthetransfer
of
engine
vibrationstothe
carbur-
etor and thereby
prevents
fuel
surgingandbubbling.
4. Exhaust
header
and
pipe,
header:
435278250
pipe:4352
78260
Someofthe
mainfeaturesof
exhaustsystemare:
(1)
Boththeheaderand
pipe
are
fabricatedfromstainlesssteel.
(2)
Theheader
is
atubulardesign,
andthe
pipe
terminatesin a
megaphone.
(3)
The
header
and
pipe
are
join-
edbya sliding
connectionto
allow
forengine
vibration
and
movement.
5. Exhaust
system
support
brackets
See
page
10for
details.
D. Lubrication
group.
1. Oil
pump,
105878
220A
Theshaft
and
rotorsin thecom-
petition
oil
pump
aremoreresis-
tanttowearandseizing.
Oil
pressure
regulator
assembly,
435214
250
Thisregulator
will maintain oil
pressure
at
6.5
-r0.5
kg/cm'.
Engineoil
cooler,105878
180
This
larger-than-stock
coolerwill
increase
coolingcapacity
by 50
percent
over
stock.
E. Cooling
group.
1.Water
pump,4801
15
010
Thecompetitionwater
pump
is
aluminumalloy.
Water
pumppulley,4801
15151
To reduce weightthis pulley is
madefrom
aluminumalloy,and
itslarger-than-stock
130mmdia-
meter
will
enhanceV-belt
life
and
reduce
the speedof the water
pump.
Radiator,105878190
The
aluminumalloy
competition
radiator'slarger
corewill
increase
enginecoolingcapacity
by60
per-
cent
overstock.
V-belt,105878154
This
notchedV-beltismoreresis-
tantto
heat.
stretchand
vibration.
F. Electricalsystem.
1. lgnitioncoil,4801
1B100
This higheroutputcoil is exclu-
sively
designedfor use with the
Mazdacompetition
capacitivedis-
charge
ignition
(CDl).
2. Hightensionwires,
coil-to-distributor:43521B110
distributor-to-spark
pl
ugs:
48011B150
These
high
tensionwires
have
a
metalwire
coreto reducevoltage
drop.
3. Distributor,4B0l 1B200
Thesearethe mainfeaturesof the
distributor:
(1)
lt is breakerless,
havinga
magnetic
trigger.
(2)
Thereis no advance mechan-
ism.
2.
3.
2.
3.

ENGINE
4. lgnitor
and
lead
wiring,
ignitor:4801
18800
lead
wiring:4801
18870
This
fully
transistorized
ignition
will provide
a stable
secondary
voltage
at high
engine
speeds.
The
lead
wiring
harness
issPeci'
fically
intended
forthis
ignition.
Alternator
and
alternator
straP,
alternator:399718
300
strap:4801
18361
Alternator
pulley
part
number:
0833-78-1
53A
The
alternator
output
is
35
amPs,
and
its
pulley
diameter
is75
mm.
Starter
stay,4352
1B
401
spacer,
'1281
17
383
Thestarter
stay
reduces
vibration
and prevents
possible
breakage
ofthe
transmission
case.
Note:
When
installing
thestaY,
the
spacer
mustbe
inserted
between
thestay
and
thestarter
motor.
Spark
plug,
4352
18600
The
heat
range
of
this
Plug
is11.5,
which
iscolder
thanstock.
Fuel
pump,
4352
1B250
This
fuel
pumP
has
an
outPut
of
100
liters/hour.
Two
of them
are
needed
to satisfY
the
racing
en'
gine's
minimum
fuel
flow
require-
ment
of
180
liters/hour.
ll. Additional Required Parts.
TheseParts
must be acquired
from
outside
sources.
1. Carburetor.
This
engine
uses'a
Weber
48lDA
ofthe
following
sPecifications:
2. Tachometer.
We
recommend
using
a mechan-
icaltachometer.
Temperature
gauges.
Minimum
requirements
include
water
and
oil
temPerature
gauges.
Oil
pressure
gauge.
We recommend
a mechanical
gauge
of
the
Belden
tube
tYPe.
5.
6.
3.
4.
7.
8.
lll. Machining
and
Fabrication
Opera-
tionsand
Procedures
A. Fabricationof oil separatortank.
1. Use
the
stock
oil
filler
PiPe.
2. The
original
filler
pipe
is
toolong
and must havea 40 mm section
removed
from the middle.
Cut it,
reweld
and
drill
holes
asshown
in
the
illustration.
3. Fabricate
the
tank
as
shown,
and
weld
ittothe
filler
PiPe.
4. After
welding,
check
foranY
Pos'
sible
oil
leaks.
Eore
xVenturi
(mm) 48x43
Emulsion
tube F-8
Main
iet fi230
Main
air
corrector.iet #130
ldle
jet #80
ldleair
corrector
iel #120
Accef
erator
nozzle #50
Needle
&seat #300
Float
level 21-23
mm
from
the
upper
surface
ofthe
float
chamber.
ii ,,i
(F"y'
i''-.1
-_*,, n,
f( ))t
Y,'t

ENGINE
B. EGR
port
block-off
plate.
1. lfyour
intermediate
housing
has
anEGR
port,
it mustbe
blocked
off witha plate.
Werecommend
aluminum
approximately
3.0
mm
thick.
2. Wheninstalling
the block-off
plate,
usea gasket
orsome sili'
conesealant.
Metering
pump
holecover.
1. lf
themetering
PumP
shaft
isnot
usedas
a
mechanicaltachometer
drive,
the hole
mustbe covered
witha plate.
Make
the Plate
of
aluminum
approximatelY
3.0
mm
thick.
2. A gasket
mustbeused
withthe
hole
cover
plate.
D. Weber
carburetor
float bowlexten-
sion.
Forcourses
with
very
tight
orlong
corners,
this
floatbowlextension
will
help
prevent
fuel
starvation.
The
floatbowlextension
fabrica-
tion
procedure
is
as
follows:
Cut
anappropriate
holeonthe
sideofthef
loatchamber.
Fabricate
thebowlextension
fromsheetaluminum
as
shown
intheillustration.
Weldthe bowl
extension
to
the
floatchamberat
four
points
only;
if
you
weldallaround
the
carburetor
maydistort.
After
welding,sealthe bowl
extensionto the floatcham-
ber
withThreeLoy.
TheThree
Loymaybeheld
in
place
with
clayorsomething
similaruntil
ithardens.
(1)
(2)
(3)
(4)
f-{
ol
Tl
lct
YY
-l I
Y

ENGINE
m
x
m+
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O'E
tr2
E3n
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3
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tr
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to
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(/)
ql
N)
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N
o)
\t
@
=
5
c)
(rl
l\)
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N
{
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q,
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5
OJ
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(r)
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el
t
A)
(t
o
-l

ENGINE
F. Cold
air
induction
box.
This
isone
of thebest
waYs
wehave
found to utilize
the high Pressure
area
atthe front
of thecarfor intake
air,
butits size,
locationand
design
are
important
to maximum
Perform'
ance.
The
important
points
of itsde-
sign
are
outlined
below.
1. Theair
intake
section
should
be
located
inthe
right
hand
sldeof
the
radiator
oPening.
We
recommend
fabricating
theair
intakeand
carburetor
cold
air
box
from
fiberglass.
The
design
of
the
carburetor
cold
air
box
isshown
below:
4. The
connecting
duct can be anY
typeof flexible
hose
witha mini'
mum
diameter
of110-120
mm.
5. Fabricate
the intakesection
to
the dimensions
shown,
and at'
tach
to
right
side
panel
as
shown
inthe
illustration.
6. Anair
f
ilterelement
isabsolutely
necessary.
lfdirt
gets
intotheen-
gine
through
lhe
intake,compres-
sion
is
lostfrom
wear
onthe
inter'
nal
gas
seals.
Forafilter
element
material,
Filtron
hasworked
verY
well. Locate
the element
at the
entrance
to the carburetor
cold
airbox.
The
intakesystem
should
be
sealed
verYtight
tocomPletelY
prohibit
any
dirt
or dust
from
en-
tering
theengine,
so
check
forair
leaks,
holes
orother
oPenings.
2.
3.
o
N
I
o
11

ENGINE
G. Competition
radiatorinstallation.
1. Fabricate
the left and right
side
panels
as shown in the illustra-
tions below.
All dimensionsare
given
in millimeters.The
holein
theright side
panel
is forthe in-
takesystem.
2. Installtheside
panels
inthe
same
location
andmannerasthestock
versions.
Side
panel
(Right)
H. Competitionoilcoolerinstallation.
There
are
two
possible
locations
for
the
oilcoolerasshown
inthe illus-
trations
below.
ln bothcases,the
competitionoilcooler
hosescanbe
used,
in eitherlhe vertical{ype or
horizontal-typemounting.
Verticaltype
Horizontal
type

il
The
firstlocation
is
referred
to
as
thevertical-type,withtheoil
cool-
er
mounted
in
frontof
theradiator
andattached
to
the
radiatorsup-
port
brackets
withrubbermounts.
The
second
location
isreferredto
as
thehorizontal-typeand
is su-
perior
to the vertical-type, as it
effectively
lowerstheoiltempera-
tureby
approximately
18' F(10'
c).
(1)
The
installationoftheoilcool-
er in the horizontallocation
requires
fabricationofmount-
ingbracketsas
shown
inthe
illustration.
(2)
lnstall
thebracketsby utiliz-
ingthe
bumper
bracket
bolts,
asshown
intheillustration.
Brackets
Oilcooler
Note:Alldimenslons
areinmm.
Checks
and
Measurements.
A. Side
housing.
1. Checks
(to
bedone
before
clean-
ing)'
(1)
In the area
where
the side
housingcontacts
and
mates
withlhe
rotor
housing,
check
all around
the coolant
Pas-
sages
forsigns
of coolant
or
gasleakage
or surface
abra-
sion.
(2)
On
the
rubbingsurface,
check
for
excessive
wear
orscuff
ing
on or in the paths
tracedbY
therotor
seals.
2. Cleaning.
Clean
off any surface
dePosits
withMEK
orpaint
thinner.
lfthe
depositsare
resistanttocleaning
witheitherofthesesolvents,use
#400-#600
sandpaperwetted
with
oil.
3. Measurements.
(1)
Surface
flatness
(side
housing
distortion).
a)To checksurface
flatness
use an accuratestraight
edgeand a set of feeler
gauges.
b)Checkthe surface
in the
four locationsshown in
Figure1.Thelimitfordis-
tortion
is 0.04
mm,and
if
this limit is exceeded
at
any
point,
the
side
housing
mustbe
replaced.
Steppedwear
from
sideseal.
a) Tochecktheside
sealwear,
usea dial indicatorwith a
sharp
tipanda suitable
dial
indicatorstand,
and ch'eck
asshown
inFigure2.
1.
2.
--
I
p
I
_Y__
(2)
I
60 >l t*
r
l'f
t,
a
i
:t
n
'I
It
!
b)
The
allowable
limitforwear
is
0.1
mm,and
if thislimit
isexceeded,
the
side
hous-
ingmustbe
replaced.
Bumper
mounting
bracket
holes
Oilcooler
1o
\
62oaq
'u
li @o
B
o
&ooo4 #o
@
Figure1
\*r-.X"#
Figure2
ENGINE
13

ENGINE
Note:
a) Pay
particular
attention
to
thespark
plug
sideof the
sidehousing;
this is the
combustion
area and is
usuallythelocation
of the
greatest
wear.
b)lf excessive
wear
rates
are
measured
over
a relatively
short
period
oftime,forin-
stance
0.1mm after2000
miles
or
less,
itmay
be
an
indication
of dirtor other
contaminants
inthe
engine
andthe
intake
airfiltering
systemshould
bechecked.
B. Stationary
gears
(front
and
rear).
1. Checks.
Visually,
checkfor
anyindications
of damage
or cracking
on the
teeth.
2. Measurements.
(1)
Insidediameter
ofbearing.
a)With
an
inside
micrometer,
measure
thefour
points
as
shown
in
Figures
3
and4.
Figure 3
a.tnJ
l::l.j'i::
..'.-'-',!.{r...i,1.:l{_.. ir.r,.',ji -...{'.-i.
Figure4
lfthe
oil
clearanceisincorrector
thesurface
isflaking,
thebearing
must
be
replaced.
(2)
Oilclearancecalculation.
Determinetheoilclearanceby
thefollowingformula:
dia.
of
journal)
Both
the
AandB
dimensions
must
beintherange
of 0.05-
0.08
mm.
3. Bearing replacement.
(1)
Bearing
removal.
To
remove
thebearing,
usea
press
andthe
bearing
puller,
part
number
49
0813235.
Re-
move
the
adaptorring
fromthe
puller,
and
press
fromthe
gear
side
asshowninFigure
5.
(2)
Bearinginstallation.
Pay
particularly
closeatten-
tiontothe
positioning
of the
clinchlock
sectionofthebear-
Installthe bearingwith this
procedure.
a)Attachthe
adaptor
ring
to
the
press
tool.
b)Makecertain
theclinchlock
is
inthe
properposition.
c) Pressthe bearingall the
waydown
untiltheadaptor
ring contactsthe gear
flange,
as
shown
inFigure
6.
A - (Min. inside
dia.)
dia.of
journal)
B = (Max. inside
dia.)
- (Max.
- (Min.
Figure
5
Figure6

ENGINE
lr
{i
ir
L
lt
li
i,
C. Measurement
of A F (a F is the
smallestclearance
between
the
rotor
andtherotor
housing
surface).
(1)
Install
outer oil seals and
springsin one side of the
rotor.
This will prevent
the
rotor contacting
and thus
scuffing
the
sidehousing
as
you
rotate
itformeasurement.
(2)
Invert
therotor
andinsert
itin
therotor
housing.
The
springs
willhold
theoil
seals
in
place.
(3)
Measurea F with a feeter
gauge,
as
shown
in Figure
7.
There are four measuring
points,
twoon each
side,
at
25mm above
andbelow
the
horizontal
centerline.
asshown
inFigure
8.
Figure
I
The
allowableclearancerange
for
A Fis
0.40-0.70mm.
Notes:
a) lf a Fisless
than
0.40
mm,
the rotor
may
contact
the
housing
athigh
speed.
b)MarkF or R, for front or
reat,on the rotors after
measuring
for
a F.
c) Usecarenot
to
damagethe
interior
surface
oftherotor
housing
with the feeler
gauge.
Rotor
houslng
(front
andrear).
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
Themaximum
allowancefor
cracksis
8
mm;iflonger
than
that,
replace
the
housing.
(2)
Rotorhousing
sides,
front
and
rear.
Checkfor
any
indications
of
gas
orcoolantleakage,
orfor
any abnormal
abrasions.lf
anyoftheseconditions
exist,
determine
the cause
before
proceeding.
Cleaning.
(1)
Clean
carbon
orany
other
de-
posits
with
MEK
or
paint
thin-
ner.
(2)
Remove
allscale
andrusttrom
the
coolant
passages
andwa-
ter
jackets.
Measurement
ofwidth.
a)This measurement
requires
a50-75mm
micrometer.
b)
Measurethe
width,
orthick-
ness,
of the housing
at
points
A, B, C and D as
shown
inFigure
10.Points
C and D areeach
20mm
steps,individually
begin-
ning
at point
B.Compare
the dimension
at point A
with the smallestof the
other
three,
whicheveritis.
lf the difference
is more
than
0.06mm,the
housing
must
bereolaced.
D.
2.
3.
S"o^
Figure7
15

ENGINE
-+-
I
Figure10
Note:
The
measuring
Point
for
the
micrometer
is
on
the
inner
side
ofthe
rubber
seal
groove.
After measuring,mark the
housing
F or R to denote
the
frontand
rearsides.
Rotor.
1. Checks
(to
bedonebefore
clean'
ing).
(1)
Rotor
condition.
Check for gas leakage,
anY
damage
to the rotor,and the
state
of combustion.
FinallY,
check
forany
marks
that
would
indicate the rotor had been
contacting the side of the
housing;
these
marks
maYbe
found,
inparticular,
inthearea
of
the
tipof
the
rotor.
(2)Internal
gear.
Check
carefully
forcracks,
ex-
treme
abrasions,
dents,
nicks
andscratches
and
other
dam'
age to the gear and teeth.
(Cracks
will sometimes aP-
pear around the sPring Pin
holeand 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
Figure11
groove
should
be cleaned
onlY
withabrush
and
kerosene
orMEK.
3. Measurements.
(1)
Using
a50-75
mm
micrometer,
measure
therotor
atthe
three
points
shown
inFigure
11.
(2)
Calculate
a Rby
the
follow'
ingformula:
A R = (Rotor
housing
width
at
point
A)
- (Max.
rotor
width
atany
point
measured
in
this
step)
Theallowable
range
of a Ris
0.13-0.17
mm.
(3)
Measurement
of a H.
Thismeasurement
requiresa
straightedge
anda
set
offeel'
er
gauges.
Check
it asshown
in Figure
12.
The allowable
rangeof a H
is
0.15-0.20
mm.
Figure12
F. Rotor
bearing.
1. Checks.
Look for abnormalabrasions
or
anysigns
of
f
laking
or
seizing.
2. Measurements.
('l)
Measure
thebearing
withthe
following
Procedure:
a) Use an inside
micrometer
and
measurethebearingat
thesix(6)
positions
shown
inFigures
13
and
14.
E.
Figure
13
16

ENGINE
3.
b)Thebearingmust
bereplac-
edifflakingisevident
over
one-halfof itstotal
areaor
if theoil
clearancesare
in-
correct.
(2)
Calculatetheoilclearance
by
thefollowingformula:
Oil
clearance
A = (Min. inside
dia.)
- (Max.
journal
dia.)
OilclearanceB = (Max. inside
dia.
- (Min.
journal
dia.)
The
allowable
range
of
ances
is
0.07-0.10
mm.
Note: There is an oversize
bearingavailable,
parl num-
ber105878135,if thestan-
dardsizewill
not
give
the
pro-
per
clearances.
Bearing
replacement.
(1)
Bearingremoval.
a) Drilloutthelockingscrew
withaTmmdrill.
b)Use the special tool, 49
0813240,
to press
outthe
bearing.
Notes:
a) Beforepressing out the
bearing,
removethe adap-
torring.
b)Pressfromthesideoppo-
sitethe
gear,
asshown
in
Figure15.
Figure15
c) After removing
the bear-
ing,
cleanthemating
sur-
face
of
therotor.
(2)
Bearinginstallation.
a) First,installthe adaptor
ring
onthe
press
tool.
b)Pressfrom
the
internal'gear
side.
c) Make certainthe clinch
lockis
properlypositioned.
d)Press
all
the
waydown
un-
til
theadaptorringcontacts
thebearing
boss,as
shown
inFigure16.
Figure16
(3)
Lockingscrewinstallation.
a) The bearingshouldbe lock-
ed firmly in place by one
locking
screwopposite
the
clinch,as shown
in Figure
17. This requires drilling
and
tapping.
Figure17
b) Before drilling,
use
thespe-
cial expander
tool to pre-
vent the bearingfrom de-
forming.
c) Drill a 3.5 mm hole to a
depthof8
mm.
d) Cutthethreadwithan M4-
0.7
tap and blow the hole
clean
withcompressed
air.
e) Insertandtightenthescrew
and
clinch.
i
J
l; .-
il
,t
:l
.{
,I
-t
l!
d
.!
.t
I
,.i
i1
i"{
,i
.t
ti
iii
,i
,l
t
'i
17
Figurel4

ENGINE
G.
f) Slightlyscrapeandsmooth
thesurfaceoverthescrew.
g)
Clean
therotorthoroughly
with kerosene
and blow
cleananddrywith
air.
Apexseal.
1. Checks.
Basically,
thesealshouldbe
visu-
ally
checkedfor
wear,
chippingin
the
groove,
cracks,andanyother
irregularities.
2. Cleaning.
Removethecarbonwith
MEK
or
paint
thinner.
3. Measurements.
(1)
Measure
height,lengthand
width
as
shownin Figure18.
Thiswillrequiretwo
microme-
ters,
a 0-25
mm anda 50-75
mm.
Markeachapexseal
to
denote
itsposition
and
loca-
tiononthe
rotor.
Measureas
follows:
a) HeightAatboth
ends.
b)
LengthB
at
one
point.
c) WidthCatbothends.
Figure
18
(2)
Measurement
of a S, the
clearance
between
the aPex
sealand
theside
housing.
a) This measurement
requires
a50-75
mm
micrometer.
b) Calculate a S by the fol-
lowingformula:
A S = (Rotor
housing
width
at point A) (Apex seal
length)
Theallowable
range
of a Sis
0.10
-r
0.01
mm.
Note:
The
rebuildable
limit
of
AS
is0.15
mm.
(3)
AdjustingaS.
lf a Sislessthanthe
lower
limitof theallowance,
it can
be adjustedby sanding
the
end of the apex seal with
#400-#600
sandpaper,
as
shown
in
Figure19.
Note:
Becareful
not
to remove
too muchmaterial
fromthe
apex
seal,thereby
increasing
the
clearance
over
limits
which
would
necessitatereplacing
the
seal.
Figure 19
Measurementof a G,
the
gap
between
the
apexsealand
the
apex
seal
groove.
This
measurementrequires
a
feeler
gauge,
and is done
as
shown
inFigure20.
The
allowable
limitof A G is
0.065
-r 0.005
mm.
Note:lf A G isintherange of
0.06-0.07
mm, the 0.06
gauge
will easily
fit intothe groove;
the 0.07
gauge will be very
tight.
(4)
18

ENGINE
(5)
AdjustingaG.
lf the
clearance
is less than
theallowable
range,sand
off
theapexsealusing
#400-#600
sandpaper
on a known
flat,
smooth
surfaceasshown
in
Figure21.
Whiledoing
this,
thesealshould
be
measured
often
to prevent
removingtoo
muchmaterial.
H. Corner seal.
1. Inspection.
Thecornersealshouldbe
inspect-
edforcracksoranysigns
of ex-
cessivewear.
2. Cleaning.
UseMEK
orpaint thinner
to re-
moveall carbondeposits,
then
wipecleanwithaclothdipped
in
thesamesolution.
Note:Donotusesandpaper.
3. Measurement.
(1)
Measurethe height and
dia-
' meterof the cornersealas
shown
in
Figure22.
Using
an inside
micrometer,
measure
theinsideof
thecor-
nerseal
groove
asshown
in
Figure23.
Calculation
of AC
(the
clear-
ancebetween
the
cornerseal
and
the
groove).
A C = (lnside
dia.ofgroove)
- (Corner
seal
dia.)
Theallowable
rangeof
a C
is
0.02-0.048
mm.
Dial
bore
gauge
Location
of
needles.
Figure
23
l. Side Seal.
1. Inspection.
Check
the
side
seal
forwearand
damage.
2. Cleaning.
Remove
allcarbon
deposits
using
MEK
or
paint
thinner,
thenwiPe
cleanwitha clothsoaked
inthe
samesolution.
3. Measurement.
(1)
Measurement
of a E (clear-
ancebetween
a cornerseal
and
asideseal).
Measure
aEwithafeeler
gauge
as
shown
inFigure24-
Theallowable
rangeof a E
is
0.05-0.15
mm,but there
is a
maximumupper
limit
for re-
builds
of0.20
mm.
(2\
(3)
i
.l
t
rll
,
:,1
tl
.'rii
'.
l
.rl
r;
".i:
1;l
't
-:i
,,
;
,i
t.;i
';;
'l €I
P \--
ill_]
Figure
22

Figure25
ENGINE
(2)
Adjusting
a E.
a E is adiusted
by removing
metal from the ends of the
sideseal.
Theideal
methodis
to use a rotary
grinder,
with
the stone
the same diameter
as the cornerseal.
However,
an
acceptable
and
morecom-
mon method
is as described
belowandshown
in
Figure25.
a) Useaflatfile.
b) Filethe end
ofthesideseal
so
its
endwill
fitthecorner
seal;
this angle shouldbe
identicaltotheoriginalan-
gle
ontheside
seal.
(3)
Pointsto
remember:
a) Usecare not to bendor
otherwisealter
thecurve
in
the side seal:
the curve
shouldmatchthatof the
groove.
lf quite a bit of material
needsto be removed,
you
should first cut the seal.
then
fileto its final shape,
to avoidbending
or other-
wisedamaging
theseal.
Afterfinishing
fittingeach
side
seal,mark
itlo corres-
pond
to its
particulargroove
onthe
rotorforlater
assem-
blv.
J. Checking
thesealstroke.
Theseal
stroke
isdefined as the
available
travelofasealspring
in 2'
its
groove,
and
is
a
functionofthe
sealspring.
1. To
measurethefree
heightof the
apex
sealspring,
place
thespring
ona level surfaceand
measure
it
witha scaleorverniercaliperas
shown
in
Figure26.
Thelower
limitis
3.5
mm.
Note:
For lhesepurposes,
the
sealstroke
isthesameas
thefree
Figure26
heightofthespring.
2. fo check the seal stroke
of the
side,
cornerandoil seals,
usea
vernier
caliper.
Eachseal
should
have
a minimum seal strokeof
0.5
mm.
Note:Check
eachseal
to conf
irm
that it will move up and down
smoothly
in
its
groove
withfinger
pressure.
K. Eccentricshaft.
Inspection.
(1)
Journal.
Makea visualinspectionfor
scratches,
nicks,
scuffing
or
any
otherabnormal
signsof
damage.
(2)
Oilgallery.
Check
theoil
gallery
formetal
chips,
particles
or any
other
contaminants,
and blow it
clear
with
air.
(3)
Blind
plug.
Check
to
make
sure
itistight,
asa loose
plug
willallow
oil
leakage.
(4)
Needlebearing.
Check
theneedlebearingby
insertingits matching trans-
missioninputshaftand
not-
ingthefit.
Look
for
any
damagetotheoil
seal.
Measurement.
(1)
Measurement
of
the
eccentric
shaft
journal
diameter.
On each journal,
measure
across
it intwodirections,X
and
Y,
as
shown
inFigure27.
Measure
each
journal
in this
way
at four
points
along
its
axis.Judge
theshaft's
condi-
tionby
any
signsofabnormal
wearor excessiveoil clear-
ance.
1.
b)
c)