like the topic says. thanks!

 

Springs aren't strong enough to pull valve closed in time.....piston smack bang, clank clank boing bong.....damn.

 

Hahaha, that is an excellent explanation. I can just hear the piston hitting the valves

 

A slightly better explanation.....

Pistons and Valves are always reciprocating in motion in an engine, meaning they move back and forth. At high RPMs they both have to keep reciprocating, moving at very high speeds. Pistons are connected solidly to the crank via connecting rods so hopefully they do not "float" out of sequence, the valves on the other hand, are held against the Cams with spring tension. At high RPMs if the springs don't have enough tension on the valve the valve will "float".....basicly the cam lobe falls away from the top of the valve stem and the spring has to play catch up to get contact back......the float causes the largest problems in "interference" engines (meaning that the piston and valves will contact if the piston is up and the valve is down at the same time) by haveing the valve floating and not retracting the piston can hit the valve and bend the stem, locking it into position, probably breaking, and screwing everything up.

 

Well said.

 

haha...thats great, reminds me of chitty-chitty bang bang

 

huh-huh you said bong.

 

Yup.....lots of white smoke.......................and blue and possibly black too.

 

Fixed a 2001 type-R TWICE.... bent all valves but engine was still in one peice.... not bad for somethign that went about 11,000rpms... redlined 3rd and droped in second.... (not mine)

amazingly the bottom end stayed in once peice... type=r = tough!!

 

Ouch!

somebody needs to learn to shift...

 

I guess valve float cannot be achieved with an auto tranny?!

 

UH OH!

Valve float can be achieved on any overhead cam motor (maybe not limited to)

Usually caused by over-revving. Springs are just curled up metal.. make them move too fast and they turn to "jelly" and stop being springs. More like a piece of metal, thats really hot!

(hence the need for hydraulic lifters in F1.. 14,000 RPM is impossible for a spring)

Dont worry, the IS300 is still under warranty!

 

i thought formula 1 were still opened by a traditional cam, but the valve was slammed shut with a pneumatic system, to get it out of the way before the piston occupies the same spot.

and they are running near 19,000rpm (according to the announcers at Monza last week)