BMW S1000RR Titanium Valves at 14,200 RPM

Because I love you all so much, I got the link:

http://www.youtube.com/watch?v=CUFsQ5lTo6g

Thats pretty cool

Want it in super slow motion though so we can really see whats happening

[squirrel_hunter]

Originally Posted by embee

It's a standard development check to determine valve rotation vs engine speed to ensure satisfactory rotation. You don't want excessive rotation as it can lead to seat wear but you do want some rotation to take place during the normal engine speed range to maintain clean seats and good sealing.

You quite often see rotation reversal too, the graph of valve rotation vs engine speed can be a bit like a hockey stick, dipping negative then going positive as speed increases.

The driving force behind valve rotation is the balance between spring helix angle and usually valve tip/follower friction. At low speed the tip friction will usually prevent rotation, as speed increases the inertia unloads the contact at full lift and rotation begins earlier in the lift cycle so rotation rates increase.

For lower speed engines it's common to introduce low friction elements into the system in order to promote rotation at low speeds, first is multigroove collets which don't grip the valve stem (often only on exhausts), for very low speed engines positive rotators can be used ("rotocoil").

Interestingly the short pivoted finger follower as in this case is usually the lowest inertia design so most suitable for very high speed valve gear.

Good game.

I noticed the rotation in the video also, was wondering if it was just a trick of the camera. So thanks for the explanation Embee and thanks for the link Pete.

omg

kleenex

this is just fantastic, a great find. thanks pete! Embee, what is generaly considered to be a "low speed" engine?

[yorkie_chris]

Originally Posted by Alpinestarhero

Embee, what is generaly considered to be a "low speed" engine?

Huge diesels, stationary engines, industrial stuff. Maybe big gennys, compressors etc.

Originally Posted by yorkie_chris

Huge diesels, stationary engines, industrial stuff. Maybe big gennys, compressors etc.

Cheers embee

[Mej]

Originally Posted by Nobbylad

Wife just walked in, I'm sat there smiling like a Cheshire cat and she's like....WTF?! "You're looking at some metal making noise?".......wimmin

lol

that vid is mad.

Here is some food for thought, the cams spin at half the speed of the crank! OMFG, I want to see how fast a piston is when the crank is at 14,200RPM!!!!!!!! Now that would be immense.

[yorkie_chris]

Move your hand up and down 230 times a second, with all that jailbait you're not shagging I bet that won't be difficult

Originally Posted by yorkie_chris

move your hand up and down 230 times a second, with all that jailbait you're not shagging i bet that won't be difficult

pmsl