Part 1
Removing and installing pistons and handling tools
Tools
Tool overview
Special tools for engine disassembly
1 - Retaining device 9778 with piston receiving element with a diameter of 97 mm.
2 - Piston receiving element 9778/1, diameter: 102 mm.
3 - Funnel 9784 or funnel 9784/2 for piston assembly, diameter: 97 mm or 102 mm.
4 - Piston assembly aid 9787, diameter: 97 mm or piston assembly aid 9787/1, diameter: 102 mm.
5 - Handle for assembly aid 9598.
6 - Disassembly tool 9764 for piston-pin circlips.
7 - Disassembly tool 9777 and assembly tool for piston pins.
8 - Assembly tool 9776 for piston-pin circlips.
9 - Centering mandrel 9782 for connecting rods and pistons.
10 - Assembly aid 9783 for pressing out pistons (cylinders 1-3) and connecting rods with pistons (cylinders 4-6).
ohne Bild - Rubber sleeves, assembly aid 9795 for protecting cylinder linings (fitted on connecting rods for cylinders 1-3).
Removal
Removing pistons - cylinder bank 1-3
Information
- The specified positions relate to removing and installing components on the engine assembly support with the engine in a vertical position.
- Mark pistons in installation position using a water-resistant marker (e.g. Edding 750).
1. Unscrew screw plug (M30 x 1.5) -1- for removing piston pins.
1.1. Replace sealing ring.
Screw plug for removing/fitting piston pins
To remove a piston-pin circlip:
2. Turn the crankshaft and vibration damper to the bottom dead center position U 1/4 and lock at this position using a locating pin 9595/1 -1-.
2.1.
U 1/4 marking on vibration damper
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.
Information
- Special tool disassembly tool 9764 for removing piston-pin circlips must only be turned in a clockwise direction.
- Always hold the tool firmly with one hand when using it.
- Replace removed piston-pin circlips.
3. Slide special tool disassembly tool 9764 through the assembly bore. The groove for the hook on the circlip -arrow- must be at 9 o'clock position when the engine is positioned vertically.
Groove position for circlip hook (9 o'clock)
4. Disassembly tool 9764 must now be pushed into the circlip.
Positioning groove of special tool 9764 in hook on circlip
4.1. Carefully turn the tool to the left and right. You should feel resistance from the hook.
5. Tighten circlip with tool 9764. To do this, turn the hexagonal handle clockwise until you feel a certain amount of resistance.
Tightening circlip with tool
6. Keep the hexagonal handle -1- tight and turn the pipe -2- clockwise until you feel a certain amount of resistance. At the same time, the cheese head bolt will move horizontally to the left from position A in the guide groove.
Tool 9764 at position A
6.1. Hold the tool firmly at the pipe -2- and press it slightly against the piston. Slowly turn the hexagonal handle -1- using spring force until the cheese head bolt is at position B.
Tool 9764 at position B
6.2. Hold the hexagonal handle -1- firmly and turn the pipe -2- clockwise until you feel a certain amount of resistance. At the same time, the cheese head bolt will move horizontally to the left from position B in the guide groove.
Tool 9764 at stop ahead of position C
6.3. Hold the tool firmly at the pipe -2- and press it slightly against the piston. Slowly turn the hexagonal handle -1- using spring force until the cheese head bolt is at position C. The circlip engages in the tool with an audible click.
Tool 9764 at position C
6.4. Slowly pull the tool and circlip -1- out of the crankcase. Dispose of old circlips.
Pulling tool 9764 out of the crankcase
To remove a piston pin:
Disassembly tool 9777
Tool 9777 for removing/fitting piston pins
1 - 53-mm insert for 2.9-liter engine (engine type MA.120)
2 - Roll pin (must be screwed in securely)
Interchangeable inserts for tool 9777
3 - 56-mm insert for 3.4 to 3.8-liter engine (engine types MA.121, MA.102, MA.101)
7. Disassembly tool 9777 must be pushed as far as it will go into the piston pin.
7.1. Hold the tool firmly at the hexagon -1- and turn the hexagon -2- anti-clockwise as far as it will go.
Sliding tool 9777 into piston pin
7.2. Pull out piston pin -1-. Inset shows the tensioned piston pin.
Removing piston pin
7.3. To loosen the piston pin, turn the rear hexagonal handle -2- clockwise until the pin can be removed.
Loosening tool 9777 on piston pin
To remove pistons:
8. Assembly aid 9783 must be inserted into the cylinder bore from the oil pan side. Then press out the piston (by tapping lightly on the handle with the ball of your hand).
8.1. Assign the correct piston pin to the piston immediately.
8.2. Fit assembly aid 9795 -1- (rubber sleeve) on the connecting rod to protect the cylinder liner.
Protective sleeves 9795 for connecting rods 1-3
9. Turn the crankshaft to the bottom dead center position U 2/5 marking at the vibration damper and lock at this position using a locating pin (tool 9595/1) -1-.
U 2/5 marking on vibration damper
9.1. Repeat steps 3 to 8 for removing piston 2.
10. Turn the crankshaft to the bottom dead center position U 3/6 marking at the vibration damper and lock at this position using a locating pin (tool 9595/1) -1-.
U 3/6 marking on vibration damper
10.1. Repeat steps 3 to 8 for removing piston 3.
11. Check piston for signs of wear.
Removing pistons - cylinder bank 4-6
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.
1. Remove crankcase half.
2. Secure the crankshaft to the main bearing in the middle using special tool holding bridge 9779 -1-.
2.1. Screw in and tighten two fastening screws -2- hand-tight.
Holding bridge 9779 for crankshaft
3. Mark pistons in installation position using a water-resistant marker.
Marking pistons 4-6
4. Screw in three fastening screws -2- for the vibration damper at the crankshaft flange.
4.1. Turn the crankshaft using special tool turning device 9773 -1- so that the connecting rod bolts can be reached.
Turning the crankshaft (without vibration damper)
5. Remove pistons and connecting rods -1- on cylinder bank 4-6.
1 - Connecting rods
2 - Connecting rod bolts
Connecting rods 4-6
5.1. Loosen and unscrew two external serration screws (M10 x 1.25 x 51) -1- on the connecting rod cap -2-.
Connecting rod cap screws
5.2. Replace screws.
6. Remove pistons 4, 5 and 6 with connecting rods.
6.1. Unscrew the grip handle on assembly aid 9783 and screw the bar -2- into a threaded bore on the connecting rod -1-. Press piston and connecting rod down out of the cylinder bore.
Pressing out pistons and connecting rods for cylinder bank 4-6
6.2. Repeat this step for pistons 5 and 6.
7. Remove connecting rods 1-3 -1- on the crankshaft.
7.1. Unscrew connecting rod bolts -2- and remove connecting rod cap and connecting rod.
Connecting rod caps on cylinder bank 1-3
7.2. Replace screws.
8. Dispose of con-rod bearing shells.
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.
Procedure for replacing pistons or connecting rods:
9. Engine type MA.102 (3.6-liter): Insert piston and connecting rod -1- in special tool retaining device 9778 (-2-).
Piston/connecting rod in retaining device 9778
9.1. Engine type MA.101 (3.8-liter): Pull off 3.6-liter piston receiving element and attach piston receiving element 9778/1.
9.2. Carefully remove piston-pin circlips with a small screwdriver.
9.3. Press out piston pin and set aside immediately with the relevant piston.
10. Check piston for signs of wear.
Assembly
Pre-fitting 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
1 - Connecting rod bolts - Initial tightening: 20 Nm (15 ft lb.) - Torque angle: 80°
Tools:
Tool 9778
1 - Retaining device 9778
2 - Inserts that can be used for the appropriate pistons: 9778 includes the insert for 3.6 and 3.4-liter pistons with a diameter of 97 mm. 9778/1 is the insert for 3.8-liter pistons with a diameter of 102 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.
1. 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.
Marking for bearing shell allocation on the crankshaft
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-.
Locking lugs for connecting rod bearings
1.4. Secure connecting rod cap with relevant connecting rod and new M10 x 1.25 x 51 screws by hand.
2. 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.
Matching number on connecting rod
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.
3. Insert pistons and connecting rods -1- or only the pistons into the retaining device 9778 (3.6 and 3.4 liter) -2-.
3.1. In the case of 3.8-liter pistons, pull off the piston receiving element and then attach the piston receiving element 9778/1.
Piston/connecting rod in retaining device 9778
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.
4. 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. A small screwdriver can be used to do this.
4.3. Press the circlip in with your thumbs and guide it to its final position with the screwdriver.
Circlip facing flywheel side - hook at 12 o'clock position (engine in vertical position)