[Barry_R]

True on the financials for the car companies - but...
The same competitive, environmental and mileage regulatory issues have driven them to far more expensive items - roller lifters, electronic fuel injection, stainless steel exhausts. If the wild claims made for those rings were even half true it would easily offset the expense.

Gapless rings in numerous configurations have been in existance since at least the 1930's - - they were designed for use in air compressors - - where a completely different set of dynamics are in play. Any patents have long since run out. Any current patent would be quickly perforated by a corporate legal staff - since prior art is so old.

As I noted - - other opinions are going to exist, and they are certainly valid in the experience of those who have them. Mine is based upon my good fortune to have had access to some very convincing data. Different opinions and approaches are what makes this engine stuff fun!