Audi TT (2007 year). Manual - part 21

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.

Pulling off spur gear
– Insert thrust piece -T10392/1- in end of crankshaft.

– Insert puller -T10392- in holes in spur gear, turn clockwise

-arrow- and screw in locking pins -A-.

– Counterhold crankshaft with ring spanner -A- and pull spur

gear off end of crankshaft by screwing in spindle with ring

spanner -B-.

Shrink-fitting spur gear

Note

♦

While heating up the new spur gear, monitor the temperature

with the temperature gauge -VAS 6519- .

♦

When the temperature reaches 200 °C, you have approx. 4

seconds to fit the spur gear on the crankshaft.

♦

A higher temperature increases the amount of time available

(220 °C = approx. 6 seconds).

♦

Make sure the end of the crankshaft is clean.

Caution

Do not exceed a maximum temperature of 240 °C; otherwise

the spur gear can become discoloured and distorted.

3. Crankshaft

– Place the new spur gear flat on a hotplate (commercially avail‐

able) and heat it to at least 200 °C, but not more than 240 °C.

The lettering must face upwards.

– Set temperature gauge -VAS 6519- to measuring range 2.
– Position temperature sensor -VAS 6519/1- on collar of spur

gear (as shown) and read off temperature at temperature

gauge.

WARNING

Risk of burns. Use suitable protective gloves for the following

steps.

– When the required temperature has been reached, pick up the

spur gear with pliers as illustrated.

Note

Take care not to damage the teeth of the spur gear.

– With the aid of fitting tool -10 - 203- , slide spur gear by hand

onto end of crankshaft as far as stop. This must be done with‐

out delay, taking care to keep the gear straight.

– Wait a few minutes to allow the spur gear to cool down, and

then install the balance shaft assembly.

⇒ “1.6 Installing a new balance shaft assembly”, page 146
⇒ “1.7 Re-installing a used balance shaft assembly”, page 149

Pistons and conrods

Note

Oil spray jet and pressure relief valve

⇒ page 80

4.1

Pistons and conrods - exploded view

1 - Bolt

❑ Renew
❑ Lubricate threads and

contact surface

❑ 30 Nm + 90°
❑ When measuring radial

clearance, tighten used

bolt to 30 Nm but not fur‐

ther

2 - Conrod bearing cap

❑ Due to the cracking

method used to sepa‐

rate the bearing cap

from the conrod in man‐

ufacture, the caps only

fit in one position and

only on the appropriate

conrod

❑ Mark cylinder allocation

in colour -B-

❑ Installation position:

Markings -A- face to‐

wards pulley end

3 - Bearing shell

❑ Installation position

⇒ page 80

❑ Mark used bearing

shells for re-installation

but not on bearing sur‐

face

❑ Note version: Upper

bearing shell (closest to

piston) is constructed

from a more wear-re‐

sistant material. Distin‐

guishing feature on new

bearing shells: black marking on bearing surface near joint

❑ Check that it is securely seated
❑ Axial clearance: wear limit: 0.37 mm
❑ Measuring radial clearance

⇒ page 82

4 - Conrod

❑ Only renew as a complete set
❑ With industrially cracked conrod bearing cap
❑ Separating parts of new conrod

⇒ page 80

❑ Mark cylinder allocation in colour -B-
❑ Installation position: Markings -A- face towards pulley end

4. Pistons and conrods

5 - Circlip

❑ Renew

6 - Piston pin

❑ If difficult to move, heat piston to approx. 60 °C
❑ Remove and install using drift -VW 222 A-

7 - Piston

❑ With combustion chamber
❑ Version fitted in vehicle may differ from illustration
❑ Mark installation position and cylinder number

⇒ page 79

❑ Checking

⇒ page 79

❑ Install using piston ring clamp
❑ Piston and cylinder dimensions

⇒ page 82

❑ Measuring cylinder bore

⇒ page 79

❑ Checking piston projection at “TDC”

⇒ page 81

8 - Piston rings

❑ Compression rings
❑ Offset gaps by 120°
❑ Use piston ring pliers to remove and install
❑ Installation position: marking “TOP” or side with lettering faces towards piston crown
❑ Measuring ring gap

⇒ page 78

❑ Measuring ring-to-groove clearance

⇒ page 79

9 - Piston ring

❑ Oil scraper ring
❑ Offset gap 120° from bottom compression ring
❑ Use piston ring pliers to remove and install
❑ Measuring ring gap

⇒ page 78

❑ Measuring ring-to-groove clearance

⇒ page 79

Measuring piston ring gap
– Insert ring at right angle to cylinder wall from above and push

down into lower cylinder opening approx. 15 mm from bottom

of cylinder.

– To do so, use a piston without rings.