AUDI A8 1998 D2 / 1.G AHA ATQ Engines Cylinder Block Crankshaft And Flywheel Component Owner's Guide
Page 31 of 33
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
Page 32 of 33
13-33
Connecting rod and connecting rod
bearings, checking clearance
Notes:
Replace the connecting rods only as a set.
Do not interchange connecting rod bearings.
Checking radial clearance
CAUTION!
DO NOT turn the crankshaft or allow it to rotate while measuring with
Plastigage in place. - Mark connecting rod bearing caps with light center punch marks before
removing.
- Remove connecting rod bearing caps. Clean bearing shells and
journals.
-
Place Plastigage over entire width of bearing journal or bearing cap.- Install connecting rod bearing cap and tighten to 20 Nm (15 ft lb).- Remove connecting rod bearing cap again.
-
Compare width of Plastigage with calibrated scale.
Pa
ge 32 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
Page 33 of 33
13-34
Clearance when new
Wear limit
0.015-0.062 mm (0.0006-
0.0024 in.) 0.12 mm (0.0047
in.)
- Always replace connecting rod bolts.
Pa
ge 33 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