221 / 1526
76
486 PL ENGINE
P
Pre-tension of connecting rod
big end bearing shells
0.010/0.040 mm
Maximum permissible difference 4.0gms max
in weight of connecting rods in
one engine
Connecting rod big end
axial play
0.100-0.400 mm
Connecting rod big end
clearance
0.035-0.081 mm
Small end clearance
0.010-0.021 mm
Camshaft journal & bearing bore dimensions :
Camshaft bearing Camshaft bearing
journal bore
journal diameter
diameter in
cylinder head
mm
mm
Standard 26/26.021
25.960/25.947
Bore dia in 1st
50.00/50.039 mm
cap for front
oil seals
Maximum permissible run
0.025 mm
out of cam shaft bearing
journal
Maximum permissible
0.1/0.3 mm
axial play of cam shaft
in installed condition
Cylinder Head (Dimension) :
Permissible unevenness Length wise 0.030mm
of cylinder head mating Cross wise 0.015mm
surface
VALVES :
VALVE TIMING
At 0.1mm actual lift (i.e. stylus is rested on tappet)
INLET OPENS
(B.T.D.C)
8
0
INLET CLOSES
(A.B.D.C)
39
0
EXHAUST OPENS (B.B.D.C)
43
0
EXHAUST CLOSES (A.T.D.C)
4
0
Valve Dimension
(Fig. 185)
INLET EXHAUST
mm mm
V
alve head dia 'A'
32.2/31.8 28.2/27.8
V
alve seat angle
45
0
+ 15
'
45
0
+ 15
'
V
alve stem dia 'E'
5.975/5.961 5.959/5.945
with 10
m
m (micron) taper
M
aximum run
0.03
0.03
out of valve face
with respect to
valve stem
V
alve seat dia 'C'
gaugeø30.6 gaugeø27
V
alve seat distance
from valve face 'B'
2.1/1.9 2.1/1.9
Valve seat end
distance from
2.7/2.3 3.2/2.8
valve face
M
aximum run out
0.03
0.03
of valve seat with
respect to valve
stem
D
istance of valve
0.7/0.95 0.7/0.95
head from cylinder
head mating surface
with crank case
Fig. 185