Porshe 911 (997). Manual - part 27

 

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Porshe 911 (997). Manual - part 27

 

 

Pressing in piston pin

3. Coat piston pin with new engine oil and press it in manually or using the plunger special tool

assembly tool 9500

.

Assembly sequence for piston-pin circlip

4. Insert new piston-pin circlip in the taper of the assembly aid 9603/1. Position the cylindrical part on the

assembly tube of the special tool assembly tool 9602/1.

Application of tool 9500/3

5. Press circlip into assembly tube using the assembly aid 9500/3.

Assembling piston pin circlip

Diagnostic system: reading out fault memory and activating systems

Assembling pistons/connecting rods, cylinder 1-3

265

6. Position assembly tube on piston eye and press piston-pin circlip into the ring groove using the

pressure pin assembly tool 9602/1. The circlip must audibly engage.

Installation position of circlip

7. Check installation position and secure fit of circlip. The lug of the circlip must always be touching

the contact surface running in the direction of the oil piston shank opposite the piston ring grooves.

8. Repeat steps for pistons/connecting rods on cylinders 2 and 3.

Piston markings

Piston markings

Piston marking

Markings on piston crown:

 Replacement pistons are available from Porsche Parts Service only in

dimensional group 'X' and in two weight groups '+' and '-'. The weight groups are listed in the table.

Marking X

 appears as a large coloured stamp in the middle of the piston crown, small as an engraved

feature -1- .

• 

Marking + or - appears

 appears as a large coloured stamp in the middle of the piston crown, small

as an engraved feature -2- .

• 

Diagnostic system: reading out fault memory and activating systems

 Piston markings

266

Weight

group

Full weight in g (with piston rings) 997 3.8l - Ø

99mm

Full weight in g (with piston rings) 997 3.6l - Ø

96mm

-

536 - 542

525 - 530

+

542 - 548

531 - 536

Installing pistons

Installing pistons

ATTENTION

Risk of damage due to particles of dirt.

Oil bores/oil ducts can become blocked up.

• 

→ When working on the engine, absolute cleanliness is essential.

→ Lay removed engine parts on a clean base and cover them without fail.

→ Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.

Note

If the piston, piston pin or piston-pin circlip are incorrectly assembled, the corresponding piston can
be pulled out of the cylinder as follows. Degrease centre of piston crown with acetone. Coat suitable
plastic mandrel with instant adhesive, allow adhesive to cure, pull out piston, remove plastic mandrel
immediately.

• 

Note

All O-rings and seals (shaft seals) and micro-encapsulated screws or lock nuts must be replaced.

• 

Note

Replace M9 x 1.25 connecting rod bolts and the piston-pin circlips that have been removed.

• 

Diagnostic system: reading out fault memory and activating systems

Piston markings

267

Note

With the help of a second person, carefully place crankcase half 4-6 in position on crankcase half 1-3.

• 

Piston/connecting rod assembly, cylinder 1-3:

1. Install gear carrier in crankcase half 1-3. → 134819 Removing and installing crankshaft - "Touching up"

section

2. Screw on belt pulley/vibration balancer with fastening screw. Turn the crankcase at the assembly support

so that cylinders 1, 2 and 3 stand vertically upwards.

3. Turn crankshaft on belt pulley/vibration balancer until the connecting-rod bearing from cylinder 1

stands vertically upwards. In doing so, the bore marked 'U4' can be fixed with the bore in the
crankcase using the fixing pin 9595/1.

Twist lock of piston ring, second groove

Note

Observe information on aligning piston ring gaps at all times.

• 

4. Prepare pre-assembled piston/connecting rod unit of cylinder 1 for installation. To do this, clamp the

connecting rod to a vice with aluminium jaws, for example. Align the gaps in the piston rings as follows:

4.1. Align the second groove on the piston ring with the twist lock

-arrow-

 .

4.2. Turn gap of piston ring, groove 1, through

180°.

4.3. Turn the gaps of the oil scraper ring so that the gaps are located at the oil piston shank area. When

doing so, the gaps of both rings and the springs should not be on top of one another (they should be
slightly offset with respect to one another).

5. Coat piston and piston rings with plenty of new engine

oil.

6. Insert connecting rod bearing in connecting rod and connecting rod cap. Coat sliding surface with

Optimol Optipit (available from Porsche Parts Service: 000.043.204.17).

Diagnostic system: reading out fault memory and activating systems

Installing pistons

268

 

 

 

 

 

 

 

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