Pre-Assembly Of Pistons And Connecting Rods
Information
- Ensure even weight distribution when installing new pistons or connecting rods .
- Only one weight group is permitted per engine .
Component overview
- Connecting rod bolts → Initial Tightening: 20 Nm (15 ft. lbs.) → Torque Angle: 80°
Tools:
- Retaining Device 9778
- Inserts that can be used for the appropriate pistons: 9778 includes the insert for 3.4-liter pistons with a diameter of 97 mm. 9778/2 is the insert for 2.7-liter pistons with a diameter of 89 mm.
Information
- The parting surface between the connecting rod and connecting rod cap is broken during the manufacturing process .
- Assign connecting rod cap to the relevant connecting rod immediately after removal .
- Also check the four-digit matching number .
- Replace connecting rod bolts .
- Replace connecting rod bearings .
- Allocate connecting-rod bearings based on the marking on the crankshaft.
- 1.1. Read off the bearing shell color from the series of letters -2-
. The Con-Rod Marking
indicates the con-rod journal. This is read from left to right. The bearings are fitted from the belt side to the flywheel side.
- G - Yellow
- B - Blue
- R - Red
- 1.2. Fit new con-rod bearing shells in the connecting rod cap and connecting rod and grease with Optimol Optipit grease (Part No. 000.043.204.17).
- 1.3. Check that the new con-rod bearing shells are seated correctly (check locking lugs) -arrow- .
- 1.4. Secure connecting rod cap with relevant connecting rod and new M10 screws by hand.
- 1.1. Read off the bearing shell color from the series of letters -2-
. The Con-Rod Marking
indicates the con-rod journal. This is read from left to right. The bearings are fitted from the belt side to the flywheel side.
- Fit pistons and connecting rods for cylinders 4-6 (the positions of the above-mentioned markings also apply for the pistons and connecting rods for cylinders 1-3).
- 2.1. The matching number -2- and data matrix code -inset- on the correctly installed connecting rod must be facing the exhaust side.
- 2.2. In contrast, the cone-shaped neck and data matrix code -1- on the piston must be facing the intake side.
- 2.3. The pistons for cylinders 1-3 are pre-fitted without connecting rods.
- Insert connecting rod with piston -1-
or only the piston into the Retaining Device 9778
(3.4-liter).
- 3.1. For 2.7-liter pistons, pull off the 3.4-liter piston receiving element and then attach the Piston Receiving Element 9778/2 .
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.
- First, fit the piston-pin circlip, which must be facing the flywheel side later.
- 4.1. Fit the circlip on the side of the piston that does not have an assembly groove for the Assembly Tool 9776 .
- 4.2. Fit the circlip -1- at the position shown. Use a small screwdriver to do this.
- 4.3. Press the circlip in with your thumbs and guide it to its final position with the screwdriver.
Pistons And Connecting Rods For Cylinders 4-6:
- Turn piston and connecting rod by 180° and fit the circlip, which must be facing the belt side later. Use special tool Assembly Tool 9776
to do this.
- 5.1. Coat piston pin with new engine oil and press it into the relevant piston/connecting rod assembly.
- 5.2. Turn the groove for the small hook on the tool -2- towards the observer.
- 5.3. Slide a new circlip -1- into the assembly tool and press the edges together.
- 5.4. Position small hook facing the groove -arrow- .
- 5.5. Turn the circlip -1- as required.
- 5.6. Pull back and hold push rod in tool. Place the pipe -1- on a hard surface. Slowly guide the push rod down and press the circlip into installation position. You should hear a distinct click.
- Assembly Tool 9776
must be positioned on the piston in such a way that the small hook is lying in the half-moon-shaped bore -arrow-
.
View of piston on the circlip -1- in the tool.
- 6.1. Hold on firmly to the tube of the tool -1- and tap the push rod slightly towards the piston with the ball of your hand -arrow- . The circlip will lock with a clearly audible click.
- 6.2. The circlip -1- must be fitted as shown. The hook is at the 9 o'clock position -2- .
- Remove piston and connecting rod from the Retaining Device 9778 .
- If piston rings will be replaced on the re-installed pistons, these can be removed and fitted by hand.CAUTION: Check installation position and avoid breakage!