SAAB WIS ONLINE

Pistons

Pistons

General data

Engine

B205E/L/R

B235R

Mean piston velocity at 5000 rpm (m/s)

13

15

Compression ratio

8,8:1

9,3:1

Nominal compression (bar)

12

14



Important

Pistons of different manufacture must not be used in the same engine. The name of the piston manufacturer is cast inside the piston.


Piston types


Engine

R

Ø

A

H

B205E/L/R

mm

74

28.65

1.4

56.2

B235R

mm

50

70

3.8

56.9



Pistons


Classification of pistons and cylinder bores

The piston classification is stamped on the piston crown roof. Piston classifications for service are:

AB

B

C

The cylinder classification is stamped on the cylinder face and is specified for each cylinder. The cylinder classifications are:

A

B

B+

They can all occur in the same cylinder block.

Piston classification

Standard A

mm

Standard AB

mm

89.9664 - 89.975

Standard B

mm

89.975 - 89.982

Standard C

mm

1st oversize (0.5)

mm

90.457 - 90.475

2nd oversize (1.0)

mm

90.957 - 90.975

Piston clearance, nominal

mm

0.025 - 0.056



Classification, piston/cylinder



A/A

mm

AB/A

mm

0.026-0.056

AB/B

mm

0.055-0.032

B/B

mm

0.025-0.055

B/B+

mm



Piston diameter

The piston diameter is measured at right angles to the gudgeon pin hole 11 mm from the bottom of the piston skirt.

Piston rings

Upper compression ring

Lower compression ring

Oil scraper ring

Thickness

mm

1.475 - 1.490

1.475 - 1.490

2.5

Side clearance in groove

mm

0.035 - 0.080

0.040 - 0.075

2.501 - 2.503

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