Volkswagen Workshop Service and Repair Manuals

Piston: Specifications

DIMENSIONS 

Piston Diameter: 
Standard:

Piston Size .............................................................................................................................................................................  79.48 mm (3.1291 inch)
Bore Size ...............................................................................................................................................................................  79.51 mm (3.1303 inch)

1st Oversize:

Piston Size .............................................................................................................................................................................  79.73 mm (3.1390 inch)
Bore Size ...............................................................................................................................................................................  79.76 mm (3.1402 inch)

2nd Oversize:

Piston Size .............................................................................................................................................................................  79.98 mm (3.1488 inch)
Bore Size ...............................................................................................................................................................................  80.01 mm (3.1500 inch)

Deviation from Cylinder Bore Dimension:

Maximum .................................................................................................................................................................................  0.10 mm (0.0039 inch)

Piston Ring Groove Clearance: 

New:

1st Compression Ring ..........................................................................................................................................  0.06-0.09 (0.0024-0.0036 inch)
2nd Compression Ring .........................................................................................................................................  0.05-0.08 (0.0020-0.0032 inch)
Oil Scraper Ring ...................................................................................................................................................  0.03-0.06 (0.0012-0.0024 inch)

Wear Limit:

1st Compression Ring ...............................................................................................................................................................  0.25 (0.0098 inch)
2nd Compression Ring ..............................................................................................................................................................  0.25 (0.0098 inch)
Oil Scraper Ring .......................................................................................................................................................................  0.15 (0.0059 inch)