Here's a slow motion video of one cycle of a valve that has gotten out of control, and is bouncing off the seat when closed.This is similar to what seems to happen in the AVL at that certain rpm around 5800 rpm, when the valve spring can't handle the harmonic surges and bounces, causing the engine to not be able to rev past that limit.The S Cams have been found to have a profile that seems to not excite this harmonic reaction, at least enough to avoid it to the extent that the engine can rev past that rpm. However, it is my feeling that accessing any rpms above the spring's harmonic frequency is probably asking for a different valve spring. So, even with the S Cams, it wouldn't be a bad idea to put in some better valve springs with a higher 1st order harmonic frequency.
What's the speed on the ground in 5th at 5800?
Wow! How many FPS can that camera handle? What's the speed on the ground in 5th at 5800?
I don't know where ACE got the video clip, but sometime back I had seen one with detailed view of valve bounce and rotation as visible from inside the engine, near the end of this video. Not an RE engine though.- http://www.youtube.com/watch?v=_REQ1PUM0rY
Give or take a couple of MPH, about 100 MPH, a standard machine will not reach these revs in top gear, but will do so in the first three gears with ease. B.W.
So going by that - Redlining an AVL might be disastrous ? I mean with the stock cams and stock top end setup?