I know there is stuff like DOHC (double over head cam) and SOHC (single over head cam). Is there such thing as like TOHC (TRIPLE over head cam) or something like that? jw..

 

SOHC means SINGLE over head cam.

And no, there is no TOHC simply because having two cams over each head is as good as it gets. One cam for intake valves, and one for exhaust valves.

What would the third cam do?

In a SOHC motor, the camshaft opens the intake and exhaust valves. (less power, lower RPM limit)

 

Lower power? Hmmm....the Raptor 700 and TRX450R are both SOHC motors. There's some weight and packaging gains.

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a camshaft turns as the motor turns in the motor by a chain (Quad), as the camshaft rotates it opens intake valves (letting in gas/air mixture) and exhaust valves (letting out exhaust), so by adding another camshaft makes it DOHC, most car motors u will see are pushrod cam setup, overhead cams are the way of the future and have more technology involved,the jap stuff now is all overhead cam setup......i dont really understand how having DOHC is any advantage over SOHC besides putting more stress on the motor and a little bit more of a redline

 

Sure there are weight and packaging gains... but imagine what they could do with a DOHC setup on those bikes. More power, more revs.

DOHC = more stress on the motor? How is that? A chain or belt drives two cams instead of one.

Instead of one camshaft opening and closing all the intake and exhaust valves, one camshaft is responsible for intake, and one for exhaust.
This is a much better setup.

Look at Hondas old 1.6 litre for example. 1.6 litre SOHC VTEC = 127 HP, 7000 RPM redline. (6800 in later motors) 1.6 litre DOHC VTEC, 160 HP, 8000 RPM redline. (7800 in later motors)

Hondas S2000 for example. (I just sold mine actually) 240 HP from a DOHC 2.0 litre, naturally asperated. Try that with a SOHC motor.

 

I've never heard of that before.

SOHC would be less peak h.p. then a DOHC, though a higher peak torque number.

 

Bah... SOHC engines typically have lower torque than DOHC motor because the dual cam motors are tuned for high RPM, high(er) HP applications.

DOHC 32V V8's make loads of low RPM torque. Its all about the engines state of tune. Speaking of tunability, a DOHC motor allows seperate timing adjustments
of the intake and exhaust camshafts.

Oh, and what is it that you havnt heard of?

 

another one of those stupid threads ne ways i agree w/ everything u r saying MR.350X

 

The advantage to DOHC is that you can have the valve angles wherever you want em.

 

I wouldnt be quick to say "THE" advantage...

Its one of the advantages.[img]i/expressions/face-icon-small-wink.gif[/img]