Removing/installing piston rings - AR03.10-P-7311SXI

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ENGINE 642 in MODEL 221

Fig 1: Identifying Piston Rings Remove/Install Components

Courtesy of MERCEDES-BENZ USA

Measure side clearance

Fig 2: Measuring Side Clearance

Courtesy of MERCEDES-BENZ USA

Measure end gap

Fig 3: Measuring End Gap

Courtesy of MERCEDES-BENZ USA

	Remove/install
1	Remove pistons		AR03.10-P-7021SXI
2	Determine end clearance of piston rings	Feeler gauge	*WH58.30-Z-1004-12A
2	Determine end clearance of piston rings	Piston ring vertical clearance	*BE03.10-P-1003-02B
3	Remove piston rings from piston	Pay attention to the installation position of the piston rings. The emblem "Top" or the name of the manufacturer must point towards the piston crown. Insert the hook spring (8) with the garter spring (4) offset 180° (arrow) to the ring gap of the bevel-edged ring (oil scraper ring) (3). Insert the plain compression ring (1) and the taper-faced hook scraper ring (2) with the ring gaps offset by 120°.
3	Remove piston rings from piston	Pliers	Fig 4
4	Determine end gap of piston rings	Insert respective piston ring into the unused area of the cylinder contact surface.
		Feeler gauge	*WH58.30-Z-1004-12A
		Piston ring end gap	*BE03.10-P-1004-02B
5	Install in the reverse order

TEST VALUES FOR PISTONS

Number	Designation			Engine 642
BE03.10-P-1003-02B	Piston ring vertical clearance	Groove 1	mm	0.12...0.16
		Groove 2	mm	0.065...0.110
		Groove 3	mm	0.03...0.07
BE03.10-P-1004-02B	Piston ring end gap	Groove 1	mm	0.40...0.55
		Groove 2	mm	0.25...0.50
		Groove 3	mm	0.20...0.40

Fig 4: Identifying Pliers (000 589 51 37 00)

Courtesy of MERCEDES-BENZ USA

COMMERCIALLY AVAILABLE TOOLS

Number	Designation
WH58.30-Z-1004-12A	Feeler gauge