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

[Random_Stranger]

You got me man, I have no idea

[RavenAegis45]

yeah its a kind of complex setup to get around your head at first. truthfully didn't understand it till I researched further into it and seen models and how they work

[Mstoochn]

yeah its a kind of complex setup to get around your head at first. truthfully didn't understand it till I researched further into it and seen models and how they work

so what are u actualy asking here.. looks like your jsut displaying facts...

and the 5s-fe really doesn't run that calmy. Loud injectors and the lack of harmonic balancer on the crank throw out more vibration that the cams would.

This post has been edited by Mstoochn: Dec 8, 2009 - 3:27 AM

[Smaay]

you have an interesting theory about vibration, too bad im an electrical engineer not mechanical, i could answer you better. but i do know that the 1ZZ and 2ZZ are chain driven and both rotate in the same direction. both those engines run fairly smooth. the 2ZZ has a loud valve train mainly due to the VVTL-i system.

[RavenAegis45]

you have an interesting theory about vibration, too bad im an electrical engineer not mechanical, i could answer you better. but i do know that the 1ZZ and 2ZZ are chain driven and both rotate in the same direction. both those engines run fairly smooth. the 2ZZ has a loud valve train mainly due to the VVTL-i system.

Yeah i've read alot about that on the 2zz-fe, but i hear the Honda B series and K series are the same way ounce the high RPM Cam profile switches over. I've driven in an S2000 and seen it operate pretty much at its redline and it feels like a B series, (I can't say how a K series or 2ZZ feels never been in one) im just curious cuz i figured most engines used same directional cams as opposed to counter rotational and obviously theres alot of other parts that deal with balancing issues but i'm just curious if the cams play a part in them as well. they do carry a good deal of weight

This post has been edited by RavenAegis45: Dec 10, 2009 - 12:37 AM

[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.

[pittfirefighter]

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

this is true.... the opposite rotation will cause the vibrations to cancel... but on all engines... the DOHC is not where the noise comes from... on the other hand, the size of the stroke has nothing to do with camshaft counter vibrations,
the counter rotating camshafts have more to do with belt vs chain than anything... adding the stress of another pulley to a belt would decrease its life significantly... so now you have a chain which will make not only more noise, but more vibrations than a belt...

[Smaay]

Yeah i've read alot about that on the 2zz-fe,

2ZZ-GE FYI except in my case 2ZZ-GTE, and yeah yeah i know how some feel about adding the T when its not factory. oh and thats gonna change to 2ZZ-GTZE real soon



This post has been edited by Smaay: Dec 10, 2009 - 9:32 AM

[pittfirefighter]

now thats a beauty ^^^

reminds me of a 7th gen 2ZZ-GTZE here in pittsburgh cept its black here

[Mstoochn]

Im confused u say 2zz-gte, but i see a SC, not turbo. 2zz-gze?
or is this a picture of someones twin charged 2zz-gtze with a hidden turbo?

[Bitter]

2zz is smooth until you bounce off rev limiter.