Piston, Engine

Piston Assembly:

NOTE: Different makes of piston must not be fitted in the same engine.

Piston Speed:
13 m/s (42.65 ft/s) at 5,000 rpm

Piston Dimensions:

NOTE: Different pistons are fitted depending on the compression ratio of the engine. Dish diameter is 64 mm (2.52 in).

Piston Dimension "A":
B202 Turbo 1985 4.7 mm (0.185 in)
Turbo 16 1986 onwards 3.85 mm (0.152 in)
B202i 1987 onwards 1.0 mm (0.040 in)

Piston Identification:

Piston Diameter:
This is measured at right angle to the piston boss: 16 mm (0.63 in) from the bottom of the skirt on Mahle pistons; and 8 mm (0.31 in) on Hepolite pistons.

Classification Of Pistons And Cylinder Bores:
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.
Cylinders are either class A or class B, both of which may occur in the same block.

NOTES:
Standard piston sizes A are not available as a spare part.
Piston clearance specification is a nominal value.

Hepolite Piston Sizes:
Standard A 89.967 - 89.977 mm (3.5420 - 3.5424 in)
Standard AB 89.977 - 89.985 mm (3.5424 - 3.5427 in)
Standard B 89.985 - 89.993 mm (3.5427 - 3.5430 in)
Standard C 89.993 - 90.009 mm (3.5430 - 3.5437 in)
First oversize (0.5 mm) 90.470 - 90.485 mm (3.5618 - 3.5624 in)
Second oversize (1.0 mm) 90.970 - 90.985 mm (3.5815 - 3.5821 in)
Piston clearance 0.015 - 0.043 mm (0.0006 - 0.0017 in)

Mahle Piston Sizes:
Standard A 89.970 - 89.980 mm (3.5421 - 3.5425 in)
Standard AB 89.980 - 89.988 mm (3.5425 - 3.5428 in)
Standard B 89.988 - 89.996 mm (3.5428 - 3.5431 in)
Standard C 89.996 - 90.012 mm (3.5431 - 3.5438 in)
First oversize (0.5 mm) 90.470 - 90.485 mm (3.5618 - 3.5624 in)
Second oversize (1.0 mm) 90.970 - 90.985 mm (3.5815 - 3.5821 in)
Piston clearance 0.011 - 0.040 mm (0.0004 - 0.0016 in)

Classification, Piston/Cylinder/Clearance:
A/A 0.030 - 0.050 mm
AB/A 0.022 - 0.040 mm
AB/B 0.032 - 0.050 mm
B/A 0.014 - 0.032 mm
B/B 0.024 - 0.042 mm