camshaft balancing

[CamKing]

In what measurement is stability improved? Rotational velocity?

On the spintron, we see a reduction of valve loft and seat bounce, at high rpm's.

That could happen from any change in mass to the shaft.

We only drill or grind a small amount from the OD of the journals. We some, but not all, we also add a counterweight to the timing gear to balance the front.
On some rare occasions, we've had to add heavy metal to the journals.
In all these different cases, the valvetrain stability was improved.
Removing mass to the journals, adding mass to the journals, adding a counterweight in front of the timing gear.
All helped, and the only constant is that each cam was balanced.

[piston guy]

Mike ,
I see the issue with a fuel pump eccentric on a Ford ( & others) and for that matter a fuel pump lobe on the cam itself . I have wondered about that for years. My thinking was it would "wobble" and create a flex between the #1 and #2 cam bearings , possibly further back. I am curious about balance of the cam by itself ( without the fuel pump lobe). The cam diameter is so small and I am surprised ( NOT disputing) balancing it would make a difference. Then you add the torsional loading etc. I do run a one piece ( heavy too)fuel pump eccentric on my Ford and will be switching to the lighter two piece and getting the assembly balanced. Thanks for you input about the Spintron findings .

[pdq67]

I am going to throw this out here for food for thought is ALL!!

I have wondered if full syn. oils just may be so slick that some of them might allow the needles to skip in the roller wheels as well as the roller wheels themselves on the cam lobes??

Have at it IF you want to comment?

I think some of, "540 Rat's", oil threads may have commented on this through the years before he kinda quit posting info about todays oils???

And as always, just trying to help.... NOT start anything.

pdq67

[Dave Koehler]

Mike ,
I see the issue with a fuel pump eccentric on a Ford ( & others) and for that matter a fuel pump lobe on the cam itself . I have wondered about that for years. My thinking was it would "wobble" and create a flex between the #1 and #2 cam bearings , possibly further back. I am curious about balance of the cam by itself ( without the fuel pump lobe). The cam diameter is so small and I am surprised ( NOT disputing) balancing it would make a difference. Then you add the torsional loading etc. I do run a one piece ( heavy too)fuel pump eccentric on my Ford and will be switching to the lighter two piece and getting the assembly balanced. Thanks for you input about the Spintron findings .

Ted Eaton has been working with those.
http://www.eatonbalancing.com/2012/12/0 ... balancing/
It's not exactly a new problem.
https://books.google.com/books?id=aSOXA ... ng&f=false

[SchmidtMotorWorks]

On the spintron, we see a reduction of valve loft and seat bounce, at high rpm's.

That could happen from any change in mass to the shaft.

Jon,

Do you think a heavier shaft would reduce changes in angular velocity? I’ve read of some bandaid attempts at this via a heavier timing gear. I really don’t understand why cam quill drives haven’t caught on with the V8 stuff.

A greater mass moment of inertia will change the natural frequency.

I saw development and testing at Daimler for noise/vibration with instrumentation and digital twin models that no racing organization could dream of having (not even F1).
The main thing that makes a significant difference in vibration on any engine component is making sure that no two connected parts have a similar excitation or natural frequency. Every part in a high performance valve-train has a natural frequency that is multiples higher than cam rotation frequency.
The only frequency that might come close, is cam torsional vibration being close to valve spring frequency, but balancing has nothing to do with torsional vibration.

[Kevin Johnson]

Components of the forces applied to a camshaft are perpendicular to the central axis causing bending (longitudinal vibration); other force components impart torsional or twisting forces along the central axis. The former would certainly be influenced by the corrections that Mike performs. Torsional forces affect the length of the torsion "spring" so there would be a coupling of the two general behaviors to a lessor or greater extent largely dependent on the surface morphology/dimensions of the camshaft.

Your argument that a perpendicular force (that could originate at any point along the length of the shaft) can be countered by a mass at the end of the shaft relies on the false premise that the shaft is a rigid body.

Thou dost presume too much.

[MadBill]

Why does this feel like deja vu all over again?

[JCR]

Not camshaft balancing but F1 timing gear damper. https://www.f1technical.net/forum/viewt ... =4&t=26642

[Kevin Johnson]

Why does this feel like deja vu all over again?

Hūsker Dū?

Yogi.jpg

[MadBill]

You read my mind Kevin...

[geraldtson]

I'm certainly no expert in this conversation but with all the forces being applied to the camshaft,it's getting the hell hammered out of it and it can't get out of there,its no surprise wear showing up somewhere? The beating it's taking many times multiplied by other valve train issues seems would be more relevant than any imbalance of such a small diameter shaft. Maybe the standard bearings are more durable? This is after all a high endurance application.

[Kevin Johnson]

Some more or less random Google results...

Space Safety and Human Performance
Barbara G. Kanki, Jean-Francois Clervoy, Gro Sandal
Butterworth-Heinemann, Nov 10, 2017 - Technology & Engineering - 944 pages

Space Safety and Human Performance provides a comprehensive reference for engineers and technical managers within aerospace and high technology companies, space agencies, operators, and consulting firms. The book draws upon the expertise of the world’s leading experts in the field and focuses primarily on humans in spaceflight, but also covers operators of control centers on the ground and behavior aspects of complex organizations, thus addressing the entire spectrum of space actors.

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Figure 4.1.5 text.gif

Comment: It is convenient for OEMs to model with finite degrees of freedom. In the real world, flexible objects (and a camshaft is a flexible object) have infinite degrees of freedom *. Oddly enough, when real-world empirical testing is done on balanced versus unbalanced camshafts in dynamic systems a change in output is observed. As Gomer would say, "Surprise, surprise, surprise!"

* Remember, there is more than one cardinality of infinite particularly when considering coupled forces. Interested students might want to study the Wilberforce Pendulum as an example of how a longitudinal oscillation can be coupled to a rotational oscillation.

https://en.wikipedia.org/wiki/Wilberforce_pendulum