Mitsubishi S12A2 User Manual

2-4
Chapter 2 SERVICE DATA
1.2 Maintenance Service Data of Basic Engine
Unit: mm [in.]
Item
Nominal
value
Standard value Limit value Remarks
Rockers
Rocker bushing inside diameter ø32 [1.26]
32.055 to 32.080
[1.2620 to 1.2630]
32.100
[1.2638]
Rocker shaft outside diameter ø32 [1.26]
31.975 to 31.991
[1.2589 to 1.2595]
31.950
[1.2579]
Valv e
Valve stem outside diameter
Inlet ø10 [0.39]
9.940 to 9.960
[0.3913 to 0.3921]
9.910
[0.3902]
Exhaust ø10 [0.39]
9.910 to 9.930
[0.3902 to 0.3909]
9.880
[0.3890]
Valve guide inside diameter ø10 [0.39]
10.000 to 10.015
[0.3937 to 0.3943]
10.060
[0.3961]
Same for both inlet and
exhaust valves.
Clearance
Between the
Bottom Face
of Valve
Bridge and
the Top Face
of Valve
Rotator
Adjusting screw side 2.5 [0.0984]
Non adjusting side 1.5 [0.0591]
Valve seat
and valve
Valve seat angle 30°
Valve s i n k a ge 0
- 0.1 to 0.1
[-0.0039 to 0.0039]
0.5 [0.0197]
Seat width
Inlet
2.08
[0.0819]
1.98 to 2.18
[0.0780 to 0.0858]
2.5 [0.0984]
Exhaust
1.85
[0.0728]
1.75 to 1.95
[0.0689 to 0.0768]
2.3 [0.0906]
Valve margin
Inlet
2.9
[0.114]
2.7 to 3.1
[0.1063 to 0.1220]
2.0 [0.098]
after refacing
Exhaust
3.0
[0.118]
2.8 to 3.2
[0.1102 to 0.1260]
Inside diameter of valve seat
counterbore
Inlet
58.000 to 58.030
[2.2835 to 2.2846]
58.09 [2.2870]
Exhaust
54.000 to 54.030
[2.1260 to 2.1272]
54.09 [2.1295]
Outside of
valve seat
Inlet
Standard
58.100 to 58.130
[2.2874 to 2.2886]
Single red line
0.03 [0.0012]
58.130 to 58.160
[2.2886 to 2.2898]
Double red lines
0.06 [0.0024]
58.160 to 58.190
[2.2898 to 2.2909]
Triple red lines
Exhaust
Standard
54.100 to 54.130
[2.1299 to 2.1311]
Double blue lines
0.03 [0.0012]
54.130 to 54.160
[2.1311 to 2.1323]
Triple blue lines
0.06 [0.0024]
54.160 to 54.190
[2.1323 to 2.1335]
Four blue lines
Valve seat interference
0.070 to 0.130
[0.0028 to 0.0051]
Valve s p r i n g
Free length 67.5 [2.6575] 66.2 [2.6063]
Squareness
A=1.5° or less
B=1.46 or less
Lf=67.5 [2.6575]
B=2.3 [0.087]
over entire
length
Installed length/load (mm [in.]/N {kgf} [lbf])
60.0 [2.36]/259 to 286
{26.41 to 29.16}
[58.22 to 64.29]
Push rod Runout 0.50 [0.0197] or less TIR
Valve
margin
Valve
sinkage
Valve
seat angle
Seat width
B
Lf
A

Mitsubishi S12A2 Specifications

General

Brand	Mitsubishi
Model	S12A2
Category	Engine
Language	English