Video: The Death of a Valve Spring

Valve springs are among the most highly abused components in a modern engine, road or racing. See what happens when they fail in this fascinating ultra-high speed video. 



In this intriguing but disturbing super-slow-motion study of an automotive valve spring at work, we can see a number of things happening, nearly all of them bad. From the beginning, we find the spring suffering severe surge and undamped oscillation. By around the 22-second mark, the valve stem itself is wobbling around and flexing in the valve guide in an alarming way. At 32 seconds in, the valve spring’s inner damper is clearly fractured in at least two pieces, and at 1:42, the primary outer spring snaps, giving up the ghost completely. Ouch. Game over.

When this failure occurs in oh, say, a NASCAR V8 at 9,000+ rpm, the engine develops a severe miss and total, catastrophic engine failure can be expected to follow soon, very soon. Modern valve springs can handle a tremendous amount of stress and abuse, but when they aren’t happy, the engine won’t be happy for long, either.

In fact, valvetrain and valve spring dynamics tend to be critical in many engines, which is why the wizards at Performance Trends, Inc. kindly posted this revealing video, which we share here. The Livonia, Michigan company offers a complete line of hardware and software analytical tools, including its powerful Engine Analyzer Pro software package, which in the Enterprise Edition includes valve spring analysis. This extreme slow-motion photography provides an excellent illustration of just what valve springs—and valve spring designers—are up against. Video below.


Valve Spring Dynamics Movie – The Enterprise Edition of Engine Analyzer Pro lets you enter details about the valve spring(s) you are using. It will actually import files from the Spring Wiz discussed in Item 1. It will then run the spring(s) in the Engine Analyzer Pro's valve train dynamics model and see what the springs are doing, if they are going into resonance, allowing the valve train to go out of control, etc. The Enterprise Pro's calculations are much more detailed than the simple Spring Wiz. And it does not say if a particular combination is good or bad. It just shows you what is happening and then you must decide if you want to use it.Please follow this link for further information about the Engine Analyzer v.3.9 Pro in The Enterprise Edition; long time customer of ours sent us a high speed movie of a valve spring pack in operation at high RPM. Here you can see the coils oscillating and the outer spring actually breaks during the movie. It really gives you an appreciation that things are not always under control, even in the most well built race engines. Please watch movie showing actual valve spring dynamics (and spring actually breaks)You need the Enterprise Edition to be able to simulate valve spring dynamics, which is a $250 add on to the Engine Analyzer Pro v3.9 B. Many customers likely own the Engine Analyzer Pro v3.9 A. If so, the 3.9 B update is $95 (with many new features, engines, etc) and the Enterprise is another $250, for $345. However, we do a package update/upgrade for $300, a $45 discount.To email us about updating or upgrading or call 248-473-9230.

Posted by Performance Trends Inc. on Monday, February 6, 2017

4 thoughts on “Video: The Death of a Valve Spring

  1. Great video. Looks like the inner damper could have been partially damaged from the beginning.

  2. I’ve been a mechanic for 45 years and have seen a lot of films/videos about various engine functions and failures, not to mention fixing the result of those failures in the shop. It’s interesting to see exactly what happens to a valve spring under normal use. It all makes perfect sense. Now a person knows why you do NOT reuse a spring that has a flaw in it….

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