Pistons
| Pistons |
| General data |
|
|
|
B205
|
B235
|
|
Mean piston speed at 5000 rpm
|
m/s
|
13
|
15
|
| Important | ||
|
Different makes of piston must not be fitted in the same engine. |
||
| Control values, pressure |
|
|
|
B205E
|
B235E/R
|
|
Compression ratio
|
|
9.3:1
|
9.3:1
|
|
Compression, maximum variation between cylinders
|
bar
|
2.0
|
2.0
|
| Piston types |
|
Engine
|
|
R
|
∅
|
A
|
H
|
|
B205E
|
mm
|
74
|
28,65
|
1,4
|
56.9
|
|
B235E/R
|
mm
|
190.5
|
80.9
|
4.35
|
56.9
|
| Classification of pistons and cylinder bores |
The piston classification is stamped on the piston crown roof. The piston classes for service are B
First oversize (+0.5)
Second oversize (+1.0)
| Piston classification |
|
AB
|
mm
|
89,964 - 89,975
|
|
B
|
mm
|
89,975 - 89,982
|
|
First oversize (+0.5)
|
mm
|
90,457 - 90,475
|
|
Second oversize (+1.0)
|
mm
|
90,957 - 90,975
|
|
Piston clearance, nominal
|
mm
|
0,025 - 0,056
|
| Piston diameter |
Piston diameter is measured at right angles to the gudgeon pin hole, 11 mm (B205 and B235) from the bottom of the piston skirt.
|
Classification, piston/cylinder
|
|
Fits cylinder bore
|
|
A/B piston fits both A and B cylinder bores
|
mm
|
90.000 - 90.020
|
|
B piston
|
mm
|
90,007 - 90,020
|
|
Permitted piston clearance
|
mm
|
0,025 - 0,056
|
| Piston rings |
|
|
|
Upper
compression ring |
Lower
compression ring |
Oil scraper ring
|
|
Thickness
|
mm
|
1.475 - 1.490
|
1.475 - 1.490
|
- 2.500
|
|
Side clearance in groove
|
mm
|
0,035 - 0,080
|
0.040 - 0.075
|
|
|
Working gap in cylinder
|
mm
|
0.300 - 0.500
|
0.300 - 0.500
|
0.260 - 1.020
|
| Gudgeon pins |
|
Diameter
|
mm
|
23.996 - 24.000
|
|
Clearance, gudgeon pin/connecting rod bush
|
mm
|
0.012 - 0.021
|
|
Length B205E
Length B235E/R |
mm
|
60
63 (with trapezoid connecting rod) |
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