Quote Originally Posted by NickG View Post
Sounds like you need a longer softer spring.
If it's a parachute style seal ?, the friction exerted by the lip expanding against the cylinder wall, can get to the point that it slows the piston down if over sprung .
And you can get into a "vicious circle scenario", where fierce acceleration creates very quick pressure build up, with higher temperatures and higher expansion and the ensuing greater friction creates even higher temperatures, even higher expansion and even greater friction......even though all of this happens so quickly, it has to have an effect......