Subaru 1600 Service Manual page 68

ENGINE
1.171112 1111
I
I 1,079 111, 1561
1 __
::s,::.and.,:.a_,d _ _ _
I
.-
~
I
t--
1,019
, 981110 1421 1,030 <11,16611
;- I '
'10.5, 14911250 350
d, '
0 . '
88319,1281
'2 E ,
~
j
18518, 1141
Q. -
I
8:.
6861" 100!
u ..
200
834
185.12111250
250 300
S"II.ne.peed .•
pm
883
19,1281:
350
350
A3·Q62
I
/
A5381
Fig.
3·29
Compression pressure Fig. 3·30 Measuring compression Fig.
3-31
Measuring vacuum
3. Intake Manifold
Vacuum
1) Warm up the engine.
3) Keep the engine at the idle speed
and read the vacuum gauge indication.
Difference be·
tween cylinders
196kPa
~
(2.0 kgJcm
2
,
28 psi)
or less
2) Disconnect the vacuum hose (air
cleaner to intake manifold) and install
the vacuum gauge to the hose fitting
on the manifold as shown in figure.
By observing the gauge needle
movement, the internal condition of
the engine can be diagnosed as
described in Table below.
- - -
..
Diagnosis of engine condition by measurement of manifold vacuum
Vacuum gauge indication
Possible engine condition
.-~
1. Needle is steady but lower than normal position.
Leakage around intake manifold gasket or carburetor
This tendency becomes more evident as engine
gasket.
temperature rises.
..--~-
2.
When engine speed is reduced slowly from higher
Back pressure too high, or exhaust muffler clogged.
speed, needle stops temporarily when it is
lowering or becomes steady above normal
position.
3,
Needle intermittently drops to position lower
Leakage around cylinder.
than normal position.
4.
Needle is steady but slightly lower than normal Retarded
ignition timing or insufficient valve
position.
clearances.
S.
Needle is steady but slightly higher than normal
Advanced ignition timing.
position.
6.
Needle drops slightly and intermittently from
Leaking valves or irregular valve clearances.
normal position.
.
7.
Needle drops suddenly and intermittently from
Sticky valves.
normal position.
S.
When engine speed is gradually increased, needle
Weak or broken valve springs.
begins to vibrate rapidly at certain speed, and
then vibration increases as engine speed increases.
9.
Needle vibrates above and below normal position Defective ignition system or incorrect carburetor idle
in narrow range.
adjustment.