Engine; Explanation And Description Of Competition Parts; Housing Group Parts; Basic Specifications - Mazda RX-7 Service Manual

Type 12A Rotary
Displacement,
per rotor 573 cc
Displacement, total
1 1 4 6 c c
Compression ratio
9 . 4 : 1
lntake porting
P e r i p h e r a l
Exhaust porting
Peripheral
Carburetion Twin throat, down draf t
Weber
L u b r i c a t i o n
Wet sump
C o o l i n g L i q u i d
l g n i t i o n Transistorized,
capacitive discharge
(cDr)
M a x i m u m a l l o w a b l e
e n g i n e s p e e d
9.000 RPM
ENGINE
Basic Specifications
Explanation and Description of
Competition Parts.
A. Housing group.
1 . R o t o r h o u s i n g , 4 3 5 2 1 0 ' 1 0 0
I t h a s t h e f o l l o w i n g d i f f e r e n c e s
f r o m t h e s t o c k h o u s i n g :
( 1 ) T h e i n t a k e p o r t i n g i s p e r i p h e r -
a l .
(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-
i n g i n s t e a d o f b e i n g a s h e e t
metal insert.
The intake and exhaust
as follows:
t i m i n g i s
2 . S i d e h o u s i n g s ,
front: 4352 10 200
intermediate: 4352 10 400
r e a r : 4 8 0 1 1 0 3 0 0
ENGINE
They differ from the stock hous-
i n g s i n t h e s e w a y s :
(1) The intake ports are filled in
s o l i d .
(2) The intermediate housing has
an oil separator tank.
:
(3) The passages for the oil pump
o n t h e f r o n t h o u s i n g a r e l a r g e r
passages.
3 . T e n s i o n b o l t s , 4 3 5 2 1 0 4 5 1 A
T h e s e a r e t h e s t o c k b o l t s w i t h
rubber bonded to them which
dampens out vibrations at certain
f requencies and prolongs bolt
l i f e .
4. Stationary gears,
front: 4352 10 500
rear:435210 550
Compared to the stock gears,
t h e s e h a v e t h e f o l l o w i n g d i f f e r -
e n c e s :
( 1 ) F o r s t r e n g t h , t h e m a t e r i a l a n d
heat treatment is different.
(2) A machined groove around the
bearing; this feature enhances
b e a r i n g l i f e .
Intake Opens 86' BTDU
C l o s e s 7 5 ' A B D C
Stationary Gear