Remove/install piston

AR03.10-S-7021EA

Remove/install piston

06.03.2020

Engine

654.9 in model 447

1

Piston

2

Connecting rod

3

Bolts

4

Connecting rod bearing cap

5

Retaining ring

6

Piston pin

7

Connecting rod bearing shell

8

Connecting rod bearing shell

9

Piston rings

 Warning

Risk of injury. Moving parts can pinch, crush or, in extreme cases even sever extremities.

No parts of the body or limbs should be within the operating area of mechanical components when moving components.

AS00.00-Z-0009-01A

 Caution

Risk of injury to skin and eyes due to handling of engine oil. Risk of poisoning caused by swallowing engine oil

Wear protective gloves, protective clothing and safety glasses.
Do not fill engine oil into beverage containers.

AS18.00-Z-0001-01A

 Caution

Risk of injury caused by scraping or cutting body parts on sharp vehicle parts

Always wear protective gloves when working on or near sharp and non-deburred vehicle parts.
Deburr repair panels.

AS00.00-Z-0017-01A

Topical note

Notes on avoiding damage through contamination and foreign objects

AH00.00-P-5000-01A



Remove

1

Remove crankcase lower section.

AR01.40-S-3100EA

2

Remove cylinder head.

AR01.30-S-5800EA

3

Clean sealing surfaces of crankcase.


Do not use any sharp-edged tools or abrasive paper.
Otherwise sealing surfaces of crankcase or piston crown can get damaged.

Assembly cleaner

*BR00.45-Z-1028-04A

4

Carefully remove combustion residues at top-land zone of cylinder bores and blow out cylinder bores with compressed air.


There must not be any combustion residues remaining in the cylinder bores.
Otherwise, pistons (1) and piston rings (9) will be damaged.


Turn engine in direction of engine rotation only.
Engine damage can occur otherwise.

 Cover the piston crowns; if necessary, place the pistons (1) on the bottom dead center (BDC).

 Counterholder

*654589004000

5

Mark installation position of pistons (1) relative to respective cylinder.

6

Check piston crowns for existing direction arrows and/or color dots.

If stamped direction arrows and/or color dots are no longer visible on already used engine



Clean piston crowns.

Assembly cleaner

*BR00.45-Z-1028-04A

If direction arrows and/or color dots are still not visible,



Apply color dots and/or direction arrows opposite output end side.

7

Mark installation position of connecting rods (2) relative to respective cylinder.


Do not interchange connecting rods (2).
Engine damage can occur otherwise.

8

Apply markings (arrows) on the connecting rod bearing caps (4) and corresponding connecting rods (2).


Connecting rods (2) and connecting rod bearing caps (4) are cracked (broken). Do not swap them or install them on the wrong side.
Otherwise connecting rods (2) and connecting rod bearing caps (4) will be damaged and engine damage will occur.

9

Remove screw/bolts (3).

10

Remove connecting rod bearing caps (4) with connecting rod bearing shells (8) from connecting rods (2).

11

Mark installation position of connecting rod bearing shells (8) relative to rod bearing caps (4).


Do not interchange connecting rod bearing shells (8) and connecting rod bearing caps (4).
Engine damage can occur otherwise.

12

Remove connecting rod bearing shells (8) from connecting rod bearing caps (4).

13

Remove pistons (1) with connecting rods (2) and connecting rod bearing shells (7) upward out of crankcase.


Do not damage oil spray nozzles.
Otherwise engine damage may occur.

14

Mark installation position of connecting rod bearing shells (7) relative to connecting rods (2).


Do not interchange connecting rod bearing shells (7) and connecting rods (2).
Engine damage can occur otherwise.

15

Remove connecting rod bearing shells (7).

16

Remove retaining rings (5).


Perform the work on a clean soft base.
Pistons (1) will otherwise be damaged.

17

Mark piston pins (6) and connecting rods (2) relative to pistons (1).


Do not interchange piston pins (6), connecting rods (2) and pistons (1).
Engine damage can occur otherwise.

18

Clamp connecting rods (2) with pistons (1) in vise.

 Use protective jaws.

19

Press piston pins (6) out of pistons (1).

20

Remove pistons (1) from connecting rods (2).

21

Remove connecting rods (2) from vise.

22

Clean all power unit components.


The power unit components must be absolutely free of soiling.
Engine damage can occur otherwise.

Assembly cleaner

*BR00.45-Z-1028-04A



Check

23

Check pistons (1), piston pins (6) and piston rings (9) for wear and damage.

Notes on the assessment of pistons and piston rings

AH03.10-P-0001-04MN

If problems occur,



Replace the corresponding piston (1).

24

Check connecting rod bearing shells (7, 8) and the connecting rod journals for wear and damage.

Notes on assessing wear on connecting rod bearings and connecting rod journals

AH03.10-P-0001-03MM

If problems occur,



Replace connecting rod bearing shells (7, 8) or crankshaft.

AR03.20-S-4351EA

25

Check connecting rod bearing caps (4) and connecting rods (2) for bluish coloration, transverse score marks and notches.

If problems occur,



Replace connecting rod bearing caps (4) and connecting rods (2).

26

Check cylinder barrels for wear and damage.

General information on inspecting cylinder walls

AH01.00-P-0300-01AMG

If problems occur,



Replace crankcase.



Measure

27

Measure cylinder bores.

AR01.40-S-9202E



Install

28

Clamp connecting rods (2) in vise.

 Use protective jaws.

29

Wet piston pins (6) and connecting rod small ends with engine oil.



Specified engine oils (service) - Overview

BB00.40-P-0223-02A

30.1

Assign new pistons (1), connecting rods (2) and piston pins (6) to each other.

If new pistons (1) were installed.

 Observe installation position and travel direction arrows.

30.2

Assign previously marked pistons (1), connecting rods (2) and piston pins (6) to each other.

If pistons (1) are reused.


Note the applied markings during removal.
Engine damage can occur otherwise.

 Observe installation position and travel direction arrows.

31

Manually press piston pins (6) into pistons (1) and connecting rods (2).

32

Install new retaining rings (5).


The opening of one of the two retaining rings (5) must point in the direction of the piston crown.
Engine damage can occur otherwise.

33

Remove connecting rods (2) with pistons (1) from vise.

34

Wet cylinder bores, connecting rod journals of the crankshaft, piston (1), piston rings (9), connecting rod bearing shells (7, 8), connecting rods (2) and connecting rod bearing caps (4) with engine oil.



Specified engine oils (service) - Overview

BB00.40-P-0223-02A

35

Twist piston ring end gaps of piston rings (9) 120° relative to each other.

36

Fit tensioning strap for piston rings (9) on piston (1) and tension.

 Tensioning strap

*000589041400

37

Insert pistons (1) with connecting rods (2) into respective cylinder bore.


Observe color dots and/or travel direction arrows.
Engine damage can occur otherwise.

38

Press pistons (1) into respective cylinder bore.


Do not damage oil spray nozzles.
Otherwise engine damage may occur.


Turn the crankshaft in the direction of engine rotation so that when the pistons (1) are placed in the cylinder bores, no connecting rods (2) come into contact with the connecting rod journals.
Otherwise damage will occur on the connecting rod (2) and crankshaft.

  Tensioning strap must always be supported on crankcase when pressing in pistons (1). If necessary reset the  tensioning strap.
Only press pistons (1) into cylinder bores to extent that  tensioning strap can be removed.

 Counterholder

*654589004000

 Tensioning strap

*000589041400

39.1

Insert new connecting rod bearing shells (7) into connecting rods (2) and new connecting rod bearing shells (8) into connecting rod bearing caps (4).

If connecting rod bearing shells (7, 8) were replaced.

AR03.10-P-6112-01OIB


Insert connecting rod bearing shells (7, 8) in non-canted manner into connecting rod bearing caps (4) and connecting rods (2).
Engine damage can occur otherwise.

39.2

Install previously marked connecting rod bearing shells (7) into connecting rods (2) and previously marked connecting rod bearing shells (8) into connecting rod bearing caps (4) at the respectively marked location.

If connecting rod bearing shells (7, 8) are reused.


Insert connecting rod bearing shells (7, 8) in non-canted manner into connecting rod bearing caps(4) and connecting rods (2).
Engine damage can occur otherwise.

40

Position connecting rod bearing caps (4) and associated connecting rods (2) on crankshaft according to applied markings (arrows).


Connecting rods (2) and connecting rod bearing caps (4) are cracked (broken). Do not mix up.
Otherwise connecting rods (2) and connecting rod bearing caps (4) will be damaged and engine damage will occur.

41

Wet new nuts (3) at thread and contact surface with engine oil.



Specified engine oils (service) - Overview

BB00.40-P-0223-02A

42

Tighten new bolts (3).

Topical note

Notes on threaded connections fastened using a tightening angle-based tightening process

AH00.00-P-0020-01A

 Bolt, connecting rod bearing cap to connecting rod

*BA03.10-N-1001-01EA

43

Crank crankshaft in the direction of engine rotation and check for unobstructed movement of crank assembly.

 Counterholder

*654589004000

If crankshaft only cranks sluggishly,



Check the assignment and correct seating of connecting rod bearing shells (7, 8).

AR03.10-P-6112-01OIB

44

Install cylinder head.

AR01.30-S-5800EA

45

Install crankcase lower section.

AR01.40-S-3100EA

 Connecting rod

Number

Designation

Engine 654.9 in model 447, 907

BA03.10-N-1001-01EA

Bolt, connecting rod bearing cap to connecting rod

First assembly (after cracking)

Initial torque

Stage 1

Nm

5

Stage 2

Nm

30

Stage 3

0

180

Final torque after loosening screws

Stage 4

Nm

5

Stage 5

Nm

30

Stage 6

0

90

Reassembly

Stage 1

Nm

5

Stage 2

Nm

30

Stage 3

0

90

Repair materials

Number

Designation

Order number

BR00.45-Z-1028-04A

Assembly cleaner

A 000 986 56 01