Are camshafts ever balanced? I realize there not large in diameter and the run

[Qikbbstang]

half engine speed.............I've watched small shafts be checked for vibration by the Predictive Maintenance guys in their lab to set their testing equipment and even small shafts can really get dancing at moderate rpm's 

[fekbmax]

Chirping over here to..  LoL. 

[Falcon67]

Never heard of it - why.  The shaft is constantly loaded with varying force as it rotates and is supported with 5 journals along it's length.  No reason I can think of to "balance" the thing even if you could with the way the lobes are placed on the shaft.

[WConley]

The camshaft produces pretty small shaking shaking forces, even at significant rpm.  I've spun up a bare SOHC camshaft on my test fixture at up to 5,500 rpm (11,000 crank rpm) with no rockers connected.  There was no noticeable vibration on the machine.

Once you attach the rockers, the accelerations of the valvetrain pieces will create significant vibration.  The machine would start buzzing pretty strongly at that same 5,500 rpm with rockers attached.  This shows that the valvetrain accelerations totally dominate the camshaft imbalance.

If Rolls Royce wants to build a car with a 9,000 rpm engine, you might see a balanced camshaft    Until then, it's not worth it.

[Joe-JDC]

Yes, camshafts do get balanced, and on high end engines almost always.  Ted Eaton does/did it for his EMC entry several years ago, but since the engines don't go above 7000 in competition, he does not do it now.  He is an engine balance specialist.  Just go to  www.eatonbalancing.com  and check out the articles.  Joe-JDC

[cjshaker]

If Rolls Royce wants to build a car with a 9,000 rpm engine, you might see a balanced camshaft    Until then, it's not worth it.

Ford is darn near hitting that with the new Mustang engine at 8500 rpms....in STOCK form   No balancing that I know of.

Knowing how harmonics are a major part of valvetrain problems, I wonder if a camshaft "damper" is an idea worth toying with? But I guess the harmonics come from the springs, and I don't know if anything related to the cam can affect that. Hmmm, spring dampers? Any theoretical engineers here?

[Autoholic]

I would bet that F1 teams balance their cams, but the cam speed that would require balancing is beyond your typical engine, even in supercars. The more important issue to sink your development money into is the cam profile. Acceleration and jerk (the rate of change in acceleration) is of the up-most importance. Too quick of a change in acceleration will result in massive spikes in jerk, this can easily cause valvetrain failure. I would say that the vibrations Bill noticed on his spintron was due to this and not camshaft imbalance. Jerk translates into impulse loading, which can be far more destructive than the force itself because you enter modes of failure that have to do with fatigue. Cam design is a very interesting topic that in practice is probably more of a dark art than a science.