SAAB WIS ONLINE

Pistons

Pistons

General data

Engine



B204i/B204L

B234i

Mean piston velocity at 5000 rpm (m/s)

13

15



Important

Pistons of different manufacture must not be used in the same engine. 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

B234i

mm

149

70

4.4

58.3



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 (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

1st oversize (0.5)

mm

90.472 - 90.488

2nd oversize (1.0)

mm

90.972 - 90.988

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 hole, 9.3 mm (B204L) or 11 mm (B204i and B234i) from the bottom edge of the piston.

Piston rings






Upper compression ring

Lower compression ring

Oil 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 pins

Diameter

mm

23.996 - 24.000

Clearance

mm

0.005 - 0.014