To increase the pressure around the shaft and maintain the seal’s integrity, certain lip seals have an extra spring looped into the flexible rubber part.

318 valve cover gasket. The old gasket must be carefully removed, and the surface of the valve cover and cylinder head cleaned before installing the new gasket. It is important to torque the bolts to the specified requirements to ensure a proper seal and prevent any leaks.
Fluorosilicone
Operating conditions such as the engine’s temperature, position, size, pressure and shaft speed largely determine which individual oil seal composition is most suitable for every individual application.
Many seals come with a garter spring, found within the backside of the seal. It provides contracting pressure against the sealing surface. Making sure the spring seats correctly within the seal is an excellent first step.
However, the new variant also comes with less good properties. Namely less flexibility and less resistance during assembly. Most damages therefore occur during the installation of PTFE oil seals.
Table 2 b): Common types of oil seals (without spring)

MVQ
Innovations in Oil Seal Manufacturing: Advancing Performance and Reliability
Use a piece of wood to scrape off all traces of the old gasket from the head and cover. If total removal proves difficult, use a broad screwdriver blade, but take care not to scratch the seating.