Pistons And Cylinder Bore, Checking

WARNING: This page is about a different car, the 2016 Volkswagen Beetle, 2015 Volkswagen Beetle, and 2014 Volkswagen Beetle. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Checking Pistons

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- With an external micrometer 75 to 100 mm, take measurement at approximately 15 mm from lower edge of piston skirt and offset 90° to piston axis.

Deviation from specified size: maximum 0.04 mm

Basic Dimension		Piston Diameter
in mm		82.465 ¹⁾
¹⁾ Measurements without graphite coating (thickness = 0.02 mm). The graphite coating wears off.

Fig 2: Checking Piston Ring Gap

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Push piston ring squarely from above down to approximately 15 mm from bottom end of cylinder. To do this use a piston without rings.

Piston Ring Dimensions in mm	New	Wear Limit
Compression ring	0.20 to 0.40	0.80
Oil scraping ring	0.25 to 0.50	0.80

Fig 3: Checking the Piston Ring Groove Clearance

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Clean the piston ring groove before checking.

Piston Ring Dimensions in mm	New	Wear Limit
1st Compression ring	0.06 to 0.09	0.20
2nd Compression ring	0.03 to 0.06	0.15
Oil scraping rings	Cannot be measured

Fig 4: Checking Cylinder Bores

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Special tools and workshop equipment required

Cylinder Dial Bore Gauge VAS6078

CAUTION:

Do not bore, hone, grind or rework the cylinder bores with workshop tools. Reworking damages the surface of the cylinder bore.

-- Using a Cylinder Dial Bore Gauge VAS 6078 measure in a diagonal sequence at three positions transversely -A- and longitudinally -B-.

Deviation from specified size: maximum 0.08 mm

Basic Dimension		Cylinder Bore Diameter
in mm		82.51

NOTE:

The cylinder bore must not be measured when the cylinder block is mounted on the Engine and Transmission Holder VAS6095 because the measurements may be incorrect.