Pistons
| Pistons |
| General data |
|
|
|
B206i/B204L
|
B234i
|
|
Piston speed at 5000 rpm
|
m/s
|
13
|
15
|
|
Different makes of piston must not be fitted in the same engine.
|
|||
| Piston dimensions |
|
Engine
|
Model year
|
|
R
|
\\
|
A
|
H
|
|
B206i
|
1994
|
mm
|
55
|
42.3
|
4.4
|
68.3
|
|
B204L
|
1994
|
mm
|
150
|
70
|
4.4
|
68.3
|
|
B234i
|
1994
|
mm
|
149
|
70
|
4.4
|
58.3
|
| Classification of pistons and cylinders |
The piston classification code is stamped on the piston crown. The codes for servicing are
AB B C The cylinder classification code is stamped on the block adjacent to each cylinder. Cylinder classification codes are
A B B+ All three cylinder classes may occur in the same block.
| Piston sizes |
|
Standard A (not a spare part)
|
mm
|
89.971 - 89.980
|
|
Standard AB
|
mm
|
89.980 - 89.989
|
|
Standard B
|
mm
|
89.989 - 90.000
|
|
Standard C
|
mm
|
90.000 - 90.013
|
|
First oversize (0.5)
|
mm
|
90.472 - 90.488
|
|
Piston clearance, nominal
|
mm
|
0.011 - 0.040
|
|
Classification, piston/cylinder
|
|
Clearance
|
|
A/A
|
mm
|
0.020 - 0.041
|
|
AB/A
|
mm
|
0.011 - 0.032
|
|
AB/B
|
mm
|
0.014 - 0.040
|
|
B/B
|
mm
|
0.006 - 0.031
|
|
B/B+
|
mm
|
0.011 - 0.041
|
| Piston diameter |
Piston diameter is measured at right angles to the gudgeon pin boss, 9.3 mm (B204L) or 11 mm (B206i and B234i) from the bottom of the piston skirt.
| Piston rings |
|
|
|
Top compression ring
|
Second compression ring
|
Scraper ring
|
|
Thickness
|
mm
|
1.728 - 1.740
|
1.978 - 1.990
|
2.976 - 3.052
|
|
Side clearance in groove
|
mm
|
0.050 - 0.082
|
0.040 - 0.072
|
|
|
Working gap in cylinder
|
mm
|
0.30 - 0.50
|
0.15 - 0.65
|
0.38 - 1.40
|
| Gudgeon pin |
|
Diameter
|
mm
|
23.996 - 24.000
|
|
Fit
|
mm
|
0.005 - 0.014
|
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