SAAB WIS ONLINE

Pistons

Pistons

General data

Engine



B204i/B204L/B204E/B204R

B235R(Viggen)

Mean piston velocity at 5000 rpm (m/s)

13

15



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



A

H

B204i

mm

55

42.3

4.4

68.3

B204L

mm

150

70

4.4

68.3

B235R

mm

50

70

3.8

56.9



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

B204

B235 (Viggen)

Standard A (not a spare part)

mm

89.971 - 89.980

89.966 - 89.975

Standard AB

mm

89.980 - 89.989

Standard B

mm

89.989 - 90.000

89.975 - 89.984

Standard C

mm

90.000 - 90.013

1st oversize (0.5)

mm

90.472 - 90.488

90.475 - 90.484

2nd oversize (1.0)

mm

90.972 - 90.988

90.975 - 90.984

Piston clearance, nominal

mm

0.011 - 0.040

0.025 - 0.044



Classification, piston/cylinder



Clearance







A/A

mm

0.020 - 0.041

0.031 - 0.069

AB/A

mm

0.011 - 0.032

AB/B

mm

0.014 - 0.040

B/B

mm

0.006 - 0.031

0.031 - 0.069

B/B+

mm

0.011 - 0.041



Piston diameter

Piston diameter is measured at right angles to the gudgeon pin hole, 9.3 mm (B204L) or 11 mm (B204i) from the bottom edge of the piston.

Piston rings






Upper compression ring

Lower compression ring

Oil scraper ring

Thickness B204

mm

1.728 - 1.740

1.475 - 1.490

- 2.500

Thickness B235

mm

1.475 - 1.490

1.978 - 1.990

2.976 - 3.052

Side clearance in groove B204

mm

0.050 - 0.082

0.040 - 0.072



Side clearance in groove B235

mm

0.020 - 0.065

0.040 - 0.075



Working gap in cylinder B204

mm

0.30 - 0.50

0.15 - 0.65

0.38 - 1.40

Working gap in cylinder B235

mm

0.300 - 0.500

0.300 - 0.500

0.260 - 1.020



Gudgeon pins





B204

B235

Diameter

mm

23.996 - 24.000

23.996 - 24.000

Clearance, gudgeon pin/connecting rod bush

mm

0.005 - 0.014

0.012 - 0.021

Length

mm

68

63