Apex Seal - Mazda RX-7 Service Manual

ENGINE
G .
f ) S l i g h t l y s c r a p e a n d s m o o t h
the surface over the screw.
g ) C l e a n t h e r o t o r t h o r o u g h l y
w i t h k e r o s e n e a n d b l o w
c l e a n a n d d r y w i t h a i r .
Apex seal.
1 . C h e c k s .
B a s i c a l l y , t h e s e a l s h o u l d b e v i s u -
a l l y c h e c k e d f o r w e a r , c h i p p i n g i n
the groove, cracks, and any other
i r r e g u l a r i t i e s .
2 . C l e a n i n g .
R e m o v e t h e c a r b o n w i t h M E K o r
p a i n t t h i n n e r .
3 . M e a s u r e m e n t s .
( 1 ) M e a s u r e h e i g h t , l e n g t h a n d
w i d t h a s s h o w n i n F i g u r e 1 8 .
T h i s w i l l r e q u i r e t w o m i c r o m e -
ters, a 0-25 mm and a 50-75
m m . M a r k e a c h a p e x s e a l t o
d e n o t e i t s p o s i t i o n a n d l o c a -
tion on the rotor. Measure as
f o l l o w s :
a ) H e i g h t A a t b o t h e n d s .
b ) L e n g t h B a t o n e p o i n t .
c) Width C at both ends.
Figure 18
( 2 ) M e a s u r e m e n t o f
a S , t h e
c l e a r a n c e b e t w e e n t h e a P e x
s e a l a n d t h e s i d e h o u s i n g .
a) This measurement requires
a 5 0 - 7 5 m m m i c r o m e t e r .
b ) C a l c u l a t e a S b y t h e f o l -
l o w i n g f o r m u l a :
A S = (Rotor housing width
at point A) (Apex seal
l e n g t h )
T h e a l l o w a b l e r a n g e o f a S i s
0 . 1 0 - r 0 . 0 1 m m .
N o t e : T h e r e b u i l d a b l e l i m i t o f
A S i s 0 . 1 5 m m .
( 3 ) A d j u s t i n g a S .
l f a S i s l e s s t h a n t h e l o w e r
l i m i t o f t h e a l l o w a n c e , i t c a n
b e a d j u s t e d b y s a n d i n g t h e
end of the apex seal with
#400-#600 sandpaper, as shown
i n F i g u r e 1 9 .
Note: Be careful not to remove
t o o m u c h m a t e r i a l f r o m t h e
a p e x s e a l , t h e r e b y i n c r e a s i n g
the clearance over limits which
w o u l d n e c e s s i t a t e r e p l a c i n g
t h e s e a l .
Figure 19
M e a s u r e m e n t o f a G , t h e g a p
between the apex seal and the
apex seal groove.
T h i s m e a s u r e m e n t r e q u i r e s a
f e e l e r g a u g e , a n d i s d o n e a s
s h o w n i n F i g u r e 2 0 .
T h e a l l o w a b l e l i m i t o f A G i s
0.065 -r 0.005 mm.
N o t e : l f A G i s i n t h e r a n g e o f
0.06-0.07 mm, the 0.06 gauge
w i l l e a s i l y f i t i n t o t h e g r o o v e ;
t h e 0 . 0 7 g a u g e w i l l b e v e r y
t i g h t .
(4)
1 8