Piston And Cylinder Bore, Checking

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-- Measure approximately 15 mm from the lower edge at a 90° angle to the piston pin axis using a 75 to 100 mm external micrometer.

Deviation from specified size: maximum 0.04 mm

		Piston Diameter
Standard dimension	mm	82.42 ¹⁾
¹⁾ Measurement without coating (thickness = 0.02 mm). The coating wears off.

Courtesy of AUDI OF AMERICA, LLC

-- Push the piston ring squarely to the cylinder wall from above down in the lower cylinder opening approximately 15 mm from bottom edge of the cylinder. To push in use a piston without rings.

Piston Ring Gap in Connection with the Two-Piece Oil Scraping Ring Dimensions in mm	New	Wear Limit
1. Compression ring	0.20 to 0.40 mm	0.80 mm
2. Compression ring	0.20 to 0.40 mm	0.80 mm
Oil Scraping Ring	0.25 to 0.50 mm	0.80 mm

PIston Ring Gap in Connection with the Three-Piece Oil Scraping Ring Dimensions in mm	New	Wear Limit
1. Compression ring	0.30 to 0.40 mm	0.60 mm
2. Compression ring	0.40 to 0.50 mm	0.70 mm
Oil Scraping Ring	Cannot be measured

Courtesy of AUDI OF AMERICA, LLC

-- Clean the piston ring groove before checking.

Piston Ring Gap in Connection with the Two-Piece Oil Scraping Ring Dimensions in mm	New	Wear Limit
1. Compression ring	0.06 to 0.09 mm	0.20 mm
2. Compression ring	0.03 to 0.06 mm	0.15 mm
Oil Scraping Ring	Cannot be measured

Piston Ring Gap in Connection with the Three-Piece Oil Scraping Ring Dimensions in mm
1. Compression ring	Cannot be measured
2. Compression ring	Cannot be measured
Oil Scraping Ring	Cannot be measured

Courtesy of AUDI OF AMERICA, LLC

Special tools and workshop equipment required

Cylinder Dial Bore Gauge :VAS6078

CAUTION:

- Never handle the cylinder bore with service equipment (drilling, honing, lapping).

-- Using a :VAS6078 measure in a diagonal sequence at three positions transversely -A- and longitudinally -B-.

Deviation from specified size: maximum 0.08 mm

Dimension	Cylinder Bore Diameter
Standard dimension	82.51 mm

NOTE:

A shadow or a shiny spot on the wall of the cylinder does not mean the cylinder bore is damaged as long as the cross-lapping is still visible.

The cylinder bore must not be measured when the cylinder block is mounted on the :VAS6095A because the measurements may be incorrect.