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That was great! Thanks for the video. The spring, valve and retainer should not rotate with this type of valvetrain and it can only do so if there is separation. That spring really has a tough job and it gets a whole lot tougher when things are going out of control.
 

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Yes because you have to remember that we're looking at a slow motion version of what's happening. The spring and valve stem are really moving around VERY rapidly, it's tough to believe that it can flex back and forth that far and that rapidly without breaking.
 

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DaveMcLain said:
That was great! Thanks for the video. The spring, valve and retainer should not rotate with this type of valvetrain and it can only do so if there is separation. That spring really has a tough job and it gets a whole lot tougher when things are going out of control.
So, is that the deal with the beehive's spinning like a top?
 

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Dave when you say seperation is causing the rotation, what do you mean by seperation? I noticed in the videos that when the rpms increased the roation speed increased before a valve event happend. Also why if the valve is opening would you have rotation as well? Spring accelerating faster than valve?
 

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Discussion Starter #9
About 20 years ago, the 460 I had in the Mustang snapped a valve (2 piece) where the stem was welded on. It happened on the 2-3 shift, the trans would "flare" on that shift. I figure since it was a nitrous pass, the flare helped cause valve float, which broke the valve. The guy that did all my machine work explained it to me that when that happens, the spring will snap the valve, due to it not following the cam. Kind of like taking a piece of string, getting some slack in it and popping it in two. You can see the valve bounce in the video.
Funny, the car still ran 7.30 (1/8) with a hole in the head, ingesting water, and sending all the pieces back through the engine. I thought I had burned a spark plug....It still ran, I had no idea of the damage inside. I have the piston with pieces of valve still stuck in it.
 

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jones said:
Am I not mistaken that Ti valves would move around a lot more?
Jones,

No, they won't move around a lot more. In essence if a stainless steel valve is experiencing valve float, and the valve weighs say 170 gms (for example), then if you replaced it with a equal size & dimensioned titanium valve that weighs 120 gms (for example),,,,,,,,then the same springs that were unable to control the stainless steel valve, will be able to control the lighter titanium valve.

The science principle that pertains to this is Sir Issac Newtons second Law of Motion. The formula is F=MxA (force=mass x acceleration). By reducing the mass (think weight) of the valve, then the force required to control the valve becomes less.

Hope this helps,
 

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Monstermiler said:
Dave when you say seperation is causing the rotation, what do you mean by seperation? I noticed in the videos that when the rpms increased the roation speed increased before a valve event happend. Also why if the valve is opening would you have rotation as well? Spring accelerating faster than valve?
Spring oscillation (movement) is so uncontrolled due to either spring tension ie pressure or fatigue that it isn't maintaining pace/contact between the valve retainer and seat. In order for the spring to spin free like that it has to have minimum (no) tension. Basically when its spinning wildly like that, the valve is not following the cam......
 

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Are we sure this video is in slow-mo? I always thought that these videos were shot in "real time" and only looked to be in slow-motion because they shoot them with a strobe light phased to the rocker RPM to better isolate the valve train action.
 

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Thanks for sharing Duane. For sure, incorrect springs could cause severe damage to an engine, specially if it you spin it at high rpm. I got a bad experience with the guy who "ported" my DOVES, i told him to put springs for a solid roller. He said he did it, but he didn,t. He put single springs. You could guess what happened. I paid the price for been a rookie.
So, use the matched spring only guys.

Homer
 

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By the way, does anybody know wich is the max lift that a DOVE-C head can support?

Thanks

Homer
 
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