Pre-Assembly Of Pistons And Connecting Rods
Information
- Assign connecting rod cap to the relevant connecting rod immediately after removal.
- Check four-digit matching number.
- Replace connecting rod bolts.
- Replace connecting rod bearings.
Information
- Ensure even weight distribution when installing new pistons or connecting rods.
- Only one weight group is permitted per engine.
Information
Marking for bearing shell allocation on the crankshaft
| G | Yellow colour marking on bearing shell |
| B | Blue colour marking on bearing shell |
| R | Red colour marking on bearing shell |
- PL marking indicates the bearing shell allocation for the con-rod journal.
- Read off from left to right.
- Fit bearings according to numbering sequence.
- Allocate connecting-rod bearings based on the marking on the crankshaft.
Retaining lugs for connecting rod bearings
- 1.1 Read off bearing shell colour from the series of letters -1- .
- 1.2 Insert new con-rod bearing shells in the connecting rod cap and connecting rod and grease with Optimal (Part No. 000.043.204.17).
- 1.3 Check that the locking lugs -arrow- are seated correctly.
- 1.4 Secure connecting rod cap with relevant connecting rod and new screws by hand.
Information
Markings on connecting rods and pistons
- The matching number -2- and data matrix code -inset- on the correctly installed connecting rod must be facing the exhaust side.
- The cone-shaped neck and data matrix code -1- on the piston must be facing the intake side.
- The positions of the listed markings also apply to pistons and connecting rods on cylinders 1 to 3.
- The pistons for cylinders 1 to 3 are pre-assembled without connecting rods.
- Fit pistons and connecting rods for cylinders 4 - 6.
- Insert connecting rod -1-
with piston or only the piston into the > 9778 - retaining device-2-
.
Piston/connecting rod in retaining device
- Pull off piston receiving element and fit > 9778/1 - piston receiving element
.WARNING: Preloaded or pressurized components
- Risk of eye injuries
- Risk of bruising
→ Wear personal protective gear.
→ Secure components to prevent them from falling off suddenly.
- Install piston-pin circlip -1-
towards the flywheel side using > 9776 - assembly tool
. The hook on the retaining ring must be at 12 o'clock position (when the engine is vertical).
Circlip on the flywheel side
- Turn piston and connecting rod by 180° and install circlip -1-
towards the belt side using > 9776 - assembly tool
.
- 6.1 Coat piston pin with new engine oil and press it into the relevant piston/connecting rod assembly.
- 6.2
Turn the groove for the small hook on the tool -2-
towards the observer.
Piston-pin circlip in assembly tool
- 6.3 Press the edges together and push the new circlip -1- into > 9776 - the assembly tool .
- 6.4
Turn the small hook towards the groove -arrow-
.
Small hook facing groove
- 6.5
Turn the circlip -1-
as required.
Piston-pin circlip in tool
- 6.6 Pull back and hold push rod in tool. Place the pipe -1- on a hard surface.
- 6.7 Slowly guide the push rod down and press the circlip into installation position until you hear a distinct noise.
Circlip in assembly position
Information
Circlip position viewed from the piston (towards belt side)
- View of piston on circlip -1- in assembly tool.
- > 9776 - Assembly tool
must be positioned on the piston in such a way that the small hook is lying in the half-moon-shaped bore -arrow-
.
Tool 9776 at assembly groove on piston
- 7.1
Tap the push rod of the assembly tool -1-
lightly towards the piston with the ball of your hand -arrow-
until the circlip engages.
Circlip on piston
- 7.2 Check the position of the hook -2- on the circlip -1- . The hook -2- must be at about 9 o'clock position.
Retaining ring on piston (view on belt side)
- 7.1
Tap the push rod of the assembly tool -1-
lightly towards the piston with the ball of your hand -arrow-
until the circlip engages.
- Remove piston and connecting rod from > 9778 - retaining device .