what are the advantages of dual overhead cams as opposed to single overhead cams?

Answer 1

Not much difference on street vehicles as daily drivers. If you are making mods you can change the valve timings with few tools in a machine shop (like increasing / decreasing valve overlap). The valve train is lighter. On motorcycles is used all the times and you can eliminate the rocker arms. The lobes will seat on top of the valve, reducing back slash and reciprocating mass. Now you can climb some RPMs.

Some engines and I think Honda, Ford and many others has engines with variable valve timing. Allowing you a good nice Torque curve from low RPMs all the way to the top.

That why a Harley engine sucks on high RPMs. Too heavy and too many reciprocating parts, it will self destroy. That is why are build for low end torque. A Buell is a "Harley" engine with overhead cams instead of overhead valves.

Answer 2

They are numerous. More Air flow thru the cyl head. Spacing the cams apart allow the cam to act directly on the valve follower . Having two cams also allows for one or both to be adjusted manually or by sprockets controlled by the engine computer, The ECM can control the cams in such a way that Exhaust Gas Recirculation is no longer necessary. And on the 307 horsepower 3.5 liter Nissan 350Z. First off who would of thought 20 years ago we would be talking about 240 HP 2.0 liter Honda SI'S and 307 HP 3.5 liter cars? The 1987 camaro with a 350 V-8 smogged up barely made 200 hp. Isn't 4 and 5 valve DOHC Cyl. Heads and electronic fuel injection great?

Answer 3

All the above answers are true, but the biggest advantage is that the owner of the car gets to say, "I've got duel overhead cams." It just rolls off the tongue and hangs in the air like a pungent perfume. For those of us who are stuck with single overhead cams, we can only dream....

Answer 4

Better efficiency which creates better horsepower. Twin cams significantly increase bottom end power.

Answer 5

Less resistance