Set Basic Position Of Camshafts - AR05.20-P-6020MRA

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Engine 274.9 in model 205

Engine 274.9 in model 253

MODIFICATION NOTES

29.05.2017

Technical information inserted

Operation step 6

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Courtesy of MERCEDES-BENZ USA

	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
	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
	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
	Notes on avoiding damage through contamination and foreign objects		AH00.00-P-5000-01A
	Remove
1	Remove cylinder head cover (3)		AR01.20-P-5014MRA
	Adjust
2	Remove camshaft positioner		AR05.20-P-7201MRA
3	Rotate engine at crankshaft center bolt in direction of engine rotation to top dead center (ignition TDC) on cylinder 1	The TDC marking on belt pulley/vibration damper must be aligned with positioning edge on timing case cover. Socket wrench bit	Fig 2
4	Rotate camshaft in basic position	Camshafts are in basic position if edge (1a) on segment disk (1) of exhaust camshaft points vertically upwards and positioning marking (2a) of segment disk (2) points vertically upwards. Socket	Fig 3
5	Attach hold-down tools (01a, 01b)	During assembly, screw in screws/bolts (04) until bearing brackets (03) lie flat on cylinder head. Holding device	Fig 1
6	Attach the bracket (02a, 02b)	The holding device is not suitable to bring the exhaust camshaft or intake camshaft in the position. This leads to damage on the brackets (02a, 02b) and also possibly to incorrect timing. Turn exhaust camshaft and intake camshaft exclusively with socket or screw/bolt (N 000000 005561) in combination with disk (A604990 0040). Otherwise, this damages the exhaust camshaft and intake camshaft. Camshafts must also be in TDC position so that brackets (02a, 02b) can be positioned and attached without pressure . Socket	Fig 3
		Holding device	Fig 1
7	Attach camshaft positioner, and tighten control valves finger-tight	: The final tightening of the control valves first take place after installation of the chain tensioner. When attaching camshaft positioners or timing chain, make sure that crankshaft does not turn.	AR05.20-P-7201MRA
	Install
8	Install the chain tensioner		AR05.10-P-7800MRA
9	Tighten control valves with final tightening		AR05.20-P-7201MRA
10	Remove brackets (02a, 02b) from hold-down tool (01a)	The hold-down tools (01a, 01b) remain attached to the cylinder head.
11	Release screws/bolts (04) at hold-down tools (01a, 01 b) until camshafts can be turned	The hold-down tools (01a, 01b) remain attached to the cylinder head.
	Check
12	Rotate engine through two revolutions in direction of engine rotation at crankshaft center bolt, and turn to top dead center (ignition TDC) on cylinder 1	The TDC marking on belt pulley/vibration damper must be aligned with positioning edge on timing case cover.
		Socket wrench bit	Fig 2
13	Position screws/bolts (04) at hold-down tools (01a, 01b)	Screw in screws/bolts (04) until bearing brackets (03) lie flat on cylinder head.
14	Check basic position of camshafts; to do this, attach brackets (02a, 02b) to hold-down tool (01a)	Attach brackets (02a, 02b) to hexagon of camshafts by hand, without using tool, until brackets (02a, 02b) lie flat on hold-down tool (01a). Damage to the holder (02a, 02b) can occur otherwise and therefore to incorrect setting of the timings. If brackets (02a, 02b) cannot be attached, repeat work procedure from operation step 2.
15	Remove brackets (02a, 02b) and hold-down tools (01a, 01b)
16	Install cylinder head cover (3)		AR01.20-P-5014MRA

Fig 1: Identifying Holding Device (270 589 01 61 00)

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Fig 2: Identifying Socket Wrench Bit (001 589 65 09 00)

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Fig 3: Identifying Socket (270 589 01 07 00)

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