Some disadvantages of NBR are poor ozone, sunlight and weather resistance as well as limited high temperature and flame resistance. For higher temperature resistance, a much better material to use is Silicone.
Sump gaskets are usually in several pieces, often with separate curved seals that fit under the front and rear main-bearing housings of the crankshaft.
Our suppliers try to provide the best quality oil seals and products are in some cases optimised to improve performance and fitment. Corteco is one of these brands, whose case studies we have listed for you.