AR03.10-P-7021AV Remove/Install Pistons

Piston removal and installation

Shown On Engine 112:

Remove

DANGER:
- Risk of death. Death may result if vehicle slips or topples from the lifting platform.
- Align vehicle between the columns of the lifting platform and position the four support plates at the lifting platform support points specified by the vehicle manufacturer.

1 Remove engine.
2.1 Detach automatic transmission from engine.
2.2 Detach manual transmission from engine.
3 Detach top part of oil pan.
4 Take off cylinder head.

NOTE: Remove intake manifold with complete wiring harness for this step.

5 Remove oil pump.

NOTE: Push back chain tensioner for this step and take off chain.

6 Remove conrod bearing cap(5).

NOTE: For this step mark connecting rod (4) and connecting rod bearing cap (5) on one side to each other.

7 Remove conrod (4) together with pistons (3) by lifting up and out.

NOTE: If pistons are used (3), the arrows indicating the driving direction and the marking of the pistons may no longer be visible because of carbon deposits. For this reason, remove the carbon deposits from the pistons. If arrows indicating the driving direction on the pistons are no longer recognizable, these must be newly marked.

8 Remove circlip (1) of piston pin (2)

NOTE: Do not damage piston (3), use a clean cloth as a base.

9 Press out piston pin (2)

Install
10 Assign piston (3) of cylinder bore.
11 Oil piston pin (2) and conrod bush.
12 Assemble piston (3) and conrod (4)

NOTE: Mount piston (3) with arrow in direction of travel.

13 Push in piston pin (2) by hand.
14 Insert circlip (1) of piston pin (2) into the groove on the piston (3)

NOTE: Do not damage piston (3), use a clean cloth as a base.

15 Oil cleaned parts (cylinder bore, conrod bearing journal, conrod bearing shells and pistons).

16 Fit on tensioning strap (10) and tension.

NOTE: Piston ring gaps must be offset 120 degrees

17 Install piston (3) with arrow pointing in direction of travel

NOTE: Rotate crankshaft far enough, so that the connecting rod when inserting piston into cylinder bore does not line up at the connecting rod journal!

18 Inspect conrod bolts (6)
- Thread and shank length.

19 Install conrod bearings and fit on conrod bearing cap (5)

CAUTION:
- The connecting rod bearing shell (7) with the oil hole (arrow) must be mounted in the connecting rod, otherwise the piston pin (2) is not greased.
- The anti-twist locks (8) of the connecting rod bearing shells (7) must be located in the grooves (9) of the conrods (4) and the connecting rod bearing cap (5).
- The connecting rod and the connecting rod bearing cap are cracked (broken) (arrow). They must not be installed the wrong way round!

20 Tighten conrod bolts (6)
21 Rotate crankshaft.

NOTE: To inspect ease of operation.

22 Install oil pump
- Ensure oil return flow check valve is correctly located.
- Clean strainer of oil pump.
- Fill oil pump with engine oil before installing so that it pumps oil when first started.

23 Fit on cylinder head.
24 Fit on top part of oil pan.
25.1 Fit on automatic transmission.
25.2 Fit on manual transmission.
26 Install engine.