Piston disassembly - component overview
| No. | Designation | Qty. | Removal | Fitting |
|---|---|---|---|---|
| 1 | Two compression rings above, one oil scraper ring below | 3 | With piston ring pliers 58 | With piston ring pliers 58 |
| 2 | Pistons | 1 | Push out from crankshaft together with connecting rod | Oil and install in crankcase with piston ring restraining strap 57 |
| 3 | Piston-pin circlip | 2 | Lever out with a small screwdriver | Install in correct position with special tool (see below) |
| 4 | Piston pins | 1 | Drive out using plunger P 9500/8 | Drive in using plunger P 9500/8 |
| 5 | Connecting rod big end and connecting-rod bearing cover | 1 | Matching numbers face one another | |
| 6 | Connecting-rod bolts M9 x 56 | 2 | Replace | Replace, apply light coat of oil, tighten in accordance with tightening specification |
| 7 | Connecting-rod bearing shells | 2 | Replace | Install retaining lug to retaining lug; retaining lugs must be inserted in corresponding grooves in connecting-rod big end and connecting-rod cover |
Identification of pistons
Markings on piston crown: Replacement pistons from Porsche Parts Service are only obtainable in one dimensional group 'X' and in two weight tolerances '+' and '-' . The weight tolerances are listed in the table.
- Marking X appears as a large colored stamp in the center of the piston crown and as a small engraved feature see scheme 35 -1-.
- Marking + or - appears as a large colored stamp in the center of the piston crown and as a small engraved feature see scheme 35 -2-.
Note. Pistons are installed as standard in three dimensional groups: I, X and II . Pistons are installed as standard in two weight tolerances: + and - . These data are all engraved on the piston crown. To uniquely identify a piston, it must be carefully cleaned (brass brush, ultrasonic bath). If, in spite of very thorough cleaning, the data are unreadable, the piston must be weighed together with piston rings, piston pin and the two circlips. Thorough cleaning (ultrasonic bath) is also absolutely essential to the weighing operation as otherwise the measurement result will be false.
1. A piston removed for repair is cleaned and identified. If it needs to be replaced, an X - piston with the identified weight tolerance + or - is ordered as a replacement part and installed.
| Weight tolerance | Full weight in g (with piston rings) |
|---|---|
| 546.6 - 540.6 | |
| + | 546.6 - 552.6 |
Component overview
| No. | Designation | Qty. | Removal | Fitting |
|---|---|---|---|---|
| 1- see scheme 91 | Bearing cover | 7 | Bearing cover 1 on the side of the vibration damper, bearing cover 5 with recess for thrust washers, retaining lugs for bearing shells on the same side | |
| 2- see scheme 91 | Bearing cover screws | 14 | > Initial tightening: 30 (22 ftlb.) Nm --> Final tightening: 180 ° | |
| 3- see scheme 91 | Bearing shells | 14 | Used bearing shells should be marked with a felt-tip pen (when not replacing). If the bearing shells are replaced, use only identical color markings. | Fit used shells at the same position (when not replacing). When replacing bearing shells, use only shells with the same color markings. Retaining lugs for bearing shells on the same side. |
| 4- see scheme 91 | Thrust washer | 2 | Replacement only for bearing cover 5. Observe the fastening, attach with lubricant with the lubricating groove facing outwards. | |
| 5- see scheme 91 | Crankshaft | 1 | Position the crankshaft so that the pulse wheel does not impinge or become damaged. Replacing the pulse wheel for speed measurement. > 134819 Removing and installing crankshaft | Subsequent work on the crankshaft is not permitted. Replace bearing shells |
| 6- see scheme 91 | Pickup (sensor) wheel | 1 | Redo test if necessary. > 134819 Removing and installing crankshaft | Redo test if necessary. > 134819 Removing and installing crankshaft |
| 7- see scheme 91 | Fastening screws | 3 | Replace > 134819 Removing and installing crankshaft | Replace > 134819 Removing and installing crankshaft |
| 8- see scheme 91 | Oil spray jet | For crankshaft bearings 2 to 7 | If the oil circuit is dirty, replacement is essential. Opening pressure 2 bars. Push in and out (by hand) using a suitable mandrel. | Push in and out (by hand) using a suitable mandrel. |
Scheme 272
| No. | Designation | Qty. | Removal | Fitting |
|---|---|---|---|---|
| 1- see scheme 92 | Fastening screw for vibration damper | 1 | > Initial tightening: 100 (74 ftlb.) Nm --> Final tightening: 90 ° | |
| 2- see scheme 92 | Vibration damper | 1 | ||
| 3- see scheme 92 | Fastening screw, M6 | 16 | > Tightening torque: 10 (7.5 ftlb.) Nm --> Tightening torque : 10 (7.5 ftlb.) Nm | |
| 4- see scheme 92 | Sealing ring: from 2005 as of engine number BFD20319 permanently integrated in joint flange -5- see scheme 92 | 1 | ||
| 5- see scheme 92 | Sealing flange | 1 | Insert using silicone sealant 000.043.300.39 | |
| 6- see scheme 92 | Cylinder block | 1 | ||
| 7- see scheme 92 | Chain case lid, bottom | 1 | Clean sealing faces. | Prepare sealing faces; insert using silicon sealant 000.043.300.39 |
| 8- see scheme 92 | Sealing ring | 1 | Installation see > 135919 Removing and installing crankshaft flywheel sealing ring - "Installing" chapter . | |
| 9- see scheme 92 | Double-mass flywheel | 1 | ||
| 10- see scheme 92 | Fastening screw for double-mass flywheel, M10 x 20 | > Initial tightening: 60 (44 ftlb.) Nm --> Final tightening : 90 ° | ||
| 11- see scheme 92 | Fastening screw, M8 x 28 | 2 | > Tightening torque: 23 (17 ftlb.) Nm Tightening torque 23 Nm (17 ftlb.) |
1 - Fastening screw for vibration damper
2 - Vibration damper
3 - Fastening screw M6
4 - Sealing ring
5 - Sealing flange
6 - Cylinder block
7 - Chain case lid, bottom
8 - Sealing ring
9 - Double-mass flywheel
10 - Fastening screw for double-mass flywheel, M10 x 20
11 - Fastening screw, M8 x 28