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.

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

Fig 1: Piston Ring Gap, Checking

Courtesy of AUDI OF AMERICA, LLC

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

Piston Ring Dimensions in mm	New	Wear Limit
1. Compression ring	0.30 to 0.40 mm	0.80 mm
2. Compression ring	0.40 to 0.50 mm	0.80 mm
Two-piece oil scraping ring	0.20 to 0.40 mm	0.80 mm
Three-piece oil scraping ring	Cannot be measured

Fig 2: Piston Ring Groove Clearance

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-- Clean the piston ring groove before checking.

Courtesy of AUDI OF AMERICA, LLC

Special tools and workshop equipment required

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-.

-	-	Cylinder Bore Diameter
Standard dimension	mm	82.51

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