Generally they are not especially efficient and have a problem with emissions. Because of their odd shape sealing them is much more difficult than a standard e

Generally they are not especially efficient and have a problem with emissions. Because of their odd shape sealing them is much more difficult than a standard engine. By design Mazda rotaries burn a little oil to keep the seals fresh. http://en.wikipedia.org/wiki/Wankel_engine#Disadvantages http://en.wikipedia.org/wiki/Wankel_engine#Disadvantages