Piston ring end gap, measuring

WARNING: This page is about a different car, the 2010 Audi A8, 2009 Audi A8, 2008 Audi A8, and 2007 Audi A8. However, it is still accessible from the selected car via links, so may be relevant.

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Slide piston ring down from above at a right angle to cylinder wall until it is approx. 15 mm from bottom edge of cylinder.
When sliding in, use a piston without piston rings.

Piston ring dimensions in mm	New	Wear limit
1. Compression ring	0.20 to 0.35	0.80
2. Compression ring	0.20 to 0.40	0.80
Oil scraping ring	0.20 to 0.40	0.80