Volvo B27A - Page 7

Group 21 Reconditioning engine
Specifications
Pistons for B 28
Pistons and liners are matched sets.
Only Mahle pistons are in use.
Weight 455±3 grams
Max weight difference between pistons in same engine 6 grams
Height, overall A- and F-engines 62.8 mm (2.4724 in)
E-engine 65.3 mm (2.5709 in)
from gudgeon pin centre to piston crown
A- and F-engines 38.8 mm (1.5276 in)
E-engine 41.3 mm (1.6260 in)
Piston float 0.020-0.040 mm (0.0007-0.0015 in)
Piston diameter, A-marked pistons 90.970-90.980 mm (3.5814-3.5818 in)
B-marked pistons 90.980-90.990 mm (3.5818-3.5822 in)
C-marked pistons 90.990-91.000 mm (3.5822-3.5826 in)
Piston diameter is measured at right-angles to gudgeon pin
bore, 8 mm (0.31 in) from bottom edge.
Diameter, gudgeon pin bore:
Marking, piston Marking, gudgeon pin
Blue Blue 23.510-23.513 mm (0.9255-0.9257 in)
White White 23.507-23.510 mm (0.9254-0.9255 in)
Red Red 23.504-23.507 mm (0.9253-0.9254 in)
Piston rings
15 mm
Ring gap measured 15 mm (0.6 in) from
lower edge of cylinder
Height.
mm
in
mm
in
3)
mm
in
Upper
compression
ring
1.478-1.490
9.0582-0.0587
0.045-0.074
0.0017-0.0029
0.40-0.60
0.0157-0.0236
Lower
compression
ring
1.978-1.990
0.0779-0.0783
0.025-0.054
0.0009-0.0212
0.40-0.60
0.0157-0.0236
Oil ring
2.629-2.731
0.1035-0.1075
0.009-0.233
0.0003-0.0091
0.38-1.45
0.0150-0.0570
Side clearance (measured with ring on piston) mm
Ring gap when checked in 91 mm (3.5826 in) cylinder (B 28),
88 mm (3.4646 in) (B 27), see fig mm
Gudgeon (piston) pins
Diameter
Marking, Marking, piston
gudgeon pin
Blue Blue (1) 23.500-23.497 mm (0.9251-0.9250 in)
White White (2) 23.497-23.494 mm (0.9250-0.9249 in)
Red Red (3) 23.494-23.491 mm (0.9249-0.9248 in)
Clearance in connecting rod 0.020-0.041 mm (0.0007-0.0016 in)
piston, Mahle 0.010-0.016 mm (0.0003-0.0006 in)
Demolin 0.014-0.020 mm (0.0006-0.0008 in)