wheel size AUDI A8 1998 D2 / 1.G AHA ATQ Engines Cylinder Block Crankshaft And Flywheel Component Service Manual

13-28
Crankshaft dimensions

Engine codes AHA, ATQ
Reconditioning dimension
Crankshaft journal diameter mm (in.)
Connecting rod journal diameter mm (in.)
maximum size (from nominal) -0.022 (0.00087) -0.022 (0.00087)
Standard (nominal dimension) 65.00 (2.559) 54.00 (2.126)
minimum size (from nominal) -0.042 (0.00165) -0.042 (0.00165)
maximum size (from nominal) -0.022 (0.00087) -0.022 (0.00087)
1st undersize (nominal dimension) 64.75 (2.549) 53.75 (2.116)
minimum size (from nominal) -0.042 (0.00165) -0.042 (0.00165)
maximum size (from nominal) -0.022 (0.00087) -0.022 (0.00087)
2nd undersize (nominal dimension) 64.50 (2.539) 53.50 (2.106)
minimum size (from nominal) -0.042 (0.00165) -0.042 (0.00165)
maximum size (from nominal) -0.022 (0.00087) -0.022 (0.00087)
3rd undersize (nominal dimension) 64.25 (2.530) 53.25 (2.096)
minimum size (from nominal) -0.042 (0.00165) -0.042 (0.00165)
Pa
ge 27 of 33 C
ylinder block, crankshaft and fl
ywheel, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE03.13.2

13-29

Pistons and piston rings


Pistons

Installation position: arrow on piston crown must point in driving direction.
CAUTION!
DO NOT scratch or scribe on piston crown. The surface has a
coating that must not be damaged.
Checking piston diameter - Mark cylinder number on piston crown using waterproof felt pen.

- Measure pistons approx. 10 mm (3/8 in.) from bottom edge at right
angle (90 ) to piston pin. Deviation from nominal size: 0.04 mm (0.0016 in.).
Pa
ge 28 of 33 C
ylinder block, crankshaft and fl
ywheel, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE03.13.2

13-30

Piston and cylinder bore dimensions

Reconditioning
dimension Piston diameter
Basic dimension 82.48 mm (3.247
in.)
1st oversize 82.74 mm (3.257
in.)

Checking piston ring side clearance
Clearance when new
Wear limit
0.02-0.08 mm (0.0008-0.0031 in.) 0.10 mm (0.004 in.)
Pa
ge 29 of 33 C
ylinder block, crankshaft and fl
ywheel, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE03.13.2

13-32

Cylinder bore, checking


Piston and cylinder bore dimensions
Engine codes AHA, ATQ
Note:
Replacement pistons are only available in the basic dimension.
CAUTION!
DO NOT measure cylinder bore dimensions while the cylinder block
is mounted on the engine stand. The cylinder block is stressed and
deformed by its own weight under these conditions and the
measurements will not be accurate. - Measure at three locations diagonally in crosswise direction -A- and
lengthwise direction -B-.
Inner bore gauge: 50-100 mm (1.96-3.94 in.)
Deviation from nominal size: max. 0.08mm (0.0031 in.)Reconditioning
dimension Piston diameter
Cylinder bore
diameter
Basic dimension 82.48 mm (3.2472
in.) 82.51 mm (3.2484
in.)
1st oversize 82.74 mm (3.2575
in.) 82.76 mm (3.2578
in.)
Pa
ge 31 of 33 C
ylinder block, crankshaft and fl
ywheel, servicin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE03.13.2