SAAB WIS ONLINE

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



8.8:1

9.3:1

Compression, maximum variation between cylinders

bar

2.0

2.0

Nominal compression

bar

12

14





Piston types

Engine



R

Ø

A

H

B205E

mm

74

28.65

1.4

56.2

B235E/R

mm

50

70

3.8

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 holes, 11 mm from the bottom of the piston.

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

0.75 - 1.00



Gudgeon pins

Diameter

mm

23.996 - 24.000

Clearance, gudgeon pin/connecting rod bush

mm

0.012 - 0.021

Length

mm

63