Mazda RX-7 - ENGINE; Basic Specifications; Explanation and Description of Competition Parts

Type 12A Rotary
Displacement,
per
rotor
573 cc
Displacement, total 1 146 cc
Compression
ratio
9.4:1
lntake
porting
Peripheral
Exhaust
porting
Peripheral
Carburetion Twin throat, down
draf t
Weber
Lubrication Wet sump
Cooling Liquid
lgnition Transistorized,
capacitive discharge
(cDr)
Maximum allowable
engine speed
9.000
RPM
ENGINE
Basic Specifications
Explanation
and
Description
of
Competition Parts.
A. Housing
group.
1. Rotor
housing,
4352
10'100
It has
the following
differences
from the
stock
housing:
(1)
The intake
porting
is
peripher-
al.
(2)
lt
is
sand cast
from lower vol-
ume
patterns.
(3)
The coolant
passages
are dif-
ferent.
(4)
The trochoid
surface
is
direct-
ly chrome
plated
onto the
cast-
ing instead
of being a sheet
metal
insert.
The
intake
and exhaust
as
follows:
timing is
2.
Side
housings,
front: 4352 10 200
intermediate:
4352 10 400
rear:4801
10300
ENGINE
They
differ
from
the stock hous-
ings
in these ways:
(1)
The intake
ports
are
filled in
solid.
(2)
The intermediate
housing has
an oil separator tank.
:
(3)
The
passages
for
the
oil
pump
on
the
front
housing
are larger
passages.
3.
Tension bolts,4352
10 451A
These
are the
stock bolts with
rubber
bonded to
them which
dampens out
vibrations
at certain
f
requencies
and
prolongs
bolt
life.
4.
Stationary
gears,
front: 4352
10 500
rear:435210
550
Compared to the stock
gears,
these have the following
differ-
ences:
(1)
For
strength, the material
and
heat
treatment is
different.
(2)
A machined
groove
around the
bearing; this feature enhances
bearing life.
Intake Opens 86'
BTDU
Closes
75'ABDC
Stationary
Gear