An Odd question about the camshafts of a 5S-FE, Camshafts, balance Options

[RavenAegis45]

Ok so in my quest to learn as much as I can about engines, I read an article on the Honda F20C engine found in the S2000 and read how it has Counter Rotating Camshaft's. So I started to look into this and most DOHC engines that drive both the camshafts by the belt have camshafts that spin in the same direction. I also realized that the shafts spinning have momentum and since 2 shafts spinning in the same direction creates double the momentum and vibration which is probably a reason why DOHC engines don't exceed 2.0L without suffering from vibrations unless using balance shafts (Aside from internal Balance issues as well). But then I started thinking about my car and realized that since the intake cam is being driven by the timing belt and the slave cam gear is driving the exhaust camshaft that means that our camshafts are also counter rotating. And assuming logic here two shafts spinning in the opposite direction at the same speed would cancel out any vibrations they might have? Assuming there both the same weight but just from looking at them I can tell the intake camshaft probably weighs a tad bit more than the exhaust since its longer to reach the cam gear. But I do notice our engines are just as smooth running as many smaller engines and I'm curious to know if the fact that our camshafts rotate against each other is another form of balance and vibrational control to keep the engine from running harshly at higher RPM's

[Hanyo]

the balance shaft you mention earlier is to help dampen that dead spot in the 4 cylinder stroke cycle. The valve train does not create as much momentium problems you see compared to the crank shaft and piston.

You would think two objects rotation in the same direction would have more momentum, but its simply not true. if it was really that beneficial to rotation mass, why don't manufactures make the cams rotate the opposite direction as the crank?

Also the 7afe and 5sfe are where never design to be reved happy motors, so using them as an example as a great engine is not a good argument.

additionally, It would be real hard to balance the valve train due to different intake and exhaust valve weights, springs, and cam lobe profiles.

Once you you look more into valve balance, the Vtec/ vvti extra set of cams on the engine must make the valve train extremely unbalance because the earlier version of those engines only had the valve change over on the intake side, and none on the exhaust.