AUDI A4 1998 B5 / 1.G AWM Engine Pistons And Connecting Rods Workshop Manual

13-79


Pistons and connecting rods,
disassembling and assembling Note:
Oil spray jet and pressure relief valve Fig. 6
,
Page 13
-85

1 -
Conrod bolt - 30 Nm +
1/4 turn (90 )
further
Always replaceOil threads and contact surfaceTo measure radial clearance use old boltTo measure radial clearance tighten to 30
Nm but not further
Pa
ge 1 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-80


2 -
Connecting rod bearing cap
Mark cylinder number -B-Installation position: Markings -A- face
towards pulley side
3 -
Bearing shells Upper bearing shell with oil bore for piston
bolt lubrication Installation position Fig. 5
, Page
13
-85

Do not interchange used bearing shells
(mark). Axial clearance New: 0.10 to 0.35 mm,
Wear limit: 0.40 mm Check radial clearance with Plastigage :
New: 0.01 to 0.05 mm, Wear limit: 0.12
mm. Do not rotate crankshaft when
checking radial clearance
Pa
ge 2 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-81


4 -
Connecting rod
Only replace as a setMark cylinder number -B-Installation position: Markings -A- face
toward pulley side With oil bore for piston pin lubrication
5 -
Circlip
6 -
Piston pin If difficult to remove, heat piston to approx.
60 C Remove and install with VW 222a
Pa
ge 3 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-82


7 -
Piston
Checking Fig. 3
, Page 13
-84
Mark installation position and cylinder
number. Arrow on piston crown points to pulley endInstall using piston ring clamp.Piston and cylinder dimensions Page 13
-86

8 -
Piston rings
Offset gaps by 120Remove and install with piston ring pliers."TOP" must face piston crownCheck ring gap Fig. 1
, Page 13
-83
Check ring to groove clearance Fig. 2
,
Page 13
-83

Pa
ge 4 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-83


Fig. 1 Checking piston ring gap
- Push ring squarely from above down to approx. 15 mm from bottom
end of cylinder. To do this, use a piston without rings. Piston ring
Dimensions in mm
New
Wear limit
1. compression ring 0.20 to 0.40 0.8
2. compression ring 0.20 to 0.40 0.8
Oil scraper ring 0.25 to 0.50 0.8

Fig. 2 Checking ring to groove clearance
- Clean groove before checking clearance.Piston ring
Dimensions in mm
New
Wear limit
1. compression ring 0.06 to 0.09 0.20
2. compression ring 0.05 to 0.08 0.20
Oil scraper ring 0.03 to 0.06 0.15
Pa
ge 5 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-84


Fig. 3 Checking piston
-
Measure pistons approx. 10 mm from lower edge of skirt, at 90 to
piston pin axis.
Permissible deviation from nominal dimension: no more than 0.04 mm

Special tools and equipment Fig. 4 Checking cylinder bores
Use internal dial gauge 50 to 100 mm
- Take measurements at 3 positions in both lateral direction -A- and
longitudinal direction -B-. Permissible deviation from nominal dimension: no more than 0.08 mm
Pa
ge 6 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-85


Fig. 5 Location of bearing shell
- Install bearing shells centrally into connecting rod or into connecting
rod bearing cap.

Distance a = 3.0 mm

Fig. 6 Oil spray jet and pressure relief valve
1 - Oil spray jet (for piston cooling)
2 - Bolt with pressure relief valve - 27 Nm

Opening pressure 1.3 to 1.6 bar
Pa
ge 7 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4

13-86

Piston and cylinder dimensions


Honing
dimension

Piston
diameter
Bore
diameter
Basic
dimension mm
80.950
1)
81.01
Oversize mm
81.450 1)
81.51

1) Dimension without graphite coating (thickness
0.02 mm). The graphite coating on the piston
skirts wears away.
Pa
ge 8 of 8 Pistons and connectin
g rods, disassemblin
g and assemblin
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.GE06.13.4