Great follow-up information. I love the howstuffworks website, it rocks.

 

Maybe we should start a thread on "how it's done".

 

there are certain advantages to cam in block desgined engines over ohc, aside from the cost factor. both gm and d/c are making variable displacement v8's that shut 4 cylinders off during a light throttle application. the only feasible way of doing this is using a ohv engine..it's almost impossbile to design an ohc with variable displacemnt. so the old lo=tech small block lives on and thrives due to technology. jackg 90seville 94k

 

Why?

IIRC Honda has a variable-displacement DOHC V6 coming out "soon."

 

got that from a gm engineer...he said it wasn't impossible but much more difficult to engineer for street use...it might have something to do with cost: the idea of vd is to save money by better fuel economy...therefore, if it's extremely expensive to design and manufacture, then it might not be cost effective...i'm geussing here...another possibility might be the vtec that honda uses: that might be the basis for the vd...once again, i'm geussing ...jackg 90 seville 94k