Audi 2003 A8, Руководство по ремонту, Страница: 80 / 252

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❑ Install using piston ring clamp
❑ Measuring cylinder bore
⇒ page 75
8 - Piston rings
❑ Offset gaps by 120°
❑ Use piston ring pliers to remove and install
❑ Marking “TOP” or side with identification mark must face piston crown
❑ Measuring ring gap
⇒ page 74
❑ Measuring ring-to-groove clearance ⇒ page 74
Measuring piston ring gap
– Insert piston ring at right angle to cylinder wall from above and
push down into lower cylinder opening approx. 15 mm from
bottom of cylinder.
– Use a piston without piston rings to push in the ring.
Piston ring new
mm
Wear limit
mm
1st compression ring 0.20 … 0.35 0.80
2nd compression ring 0.20 … 0.40 0.80
Oil scraper ring 0.20 … 0.40
–
1)
•
1)
Specification not yet available.
Measuring ring-to-groove clearance
– Clean groove in piston before checking clearance.
Piston ring new
mm
Wear limit
mm
1st compression ring 0.035 … 0.085 0.200
2nd compression ring 0.005 … 0.045 0.200
Oil scraper ring 0.01 … 0.05 0.15
Checking piston
– Using a micrometer (75 ... 100 mm), measure approx. 15 mm
from the lower edge, perpendicular to the piston pin axis.
• Maximum deviation from nominal dimension: 0.03 mm.
Nominal dimension
⇒ “4.2 Piston and cylinder dimensions”, page 76 .
Audi A8 2003 ➤
10-cylinder direct petrol injection engine (5.2 ltr. 4-valve), mechanics - Edition 10.2013
74
Rep. gr.13 - Crankshaft group