Great Read on pushrods by C&D

[SilverPhoenix]

[SilviaS15Cwest]

That was the first article that I read when I got mine. Very interesting to see the advantages, cause all you hear anymore is people talking about how these engines arent that good. I liked the part where he says that they meet the power requirement (405 hp) why would they need to go beyond that?... For now...

[gtx28]

That was a good article, my only q is that although you would add size and weight, are the dohc motors producing more or less power per ci im curious, on a naturaly asperated motor who produces more per ci dohc, or ohv. Just a thought.

[T-Bird]

OHC motors make more power on average than pushrod motors due to less parasitic loss and other reasons

[RC45]

You need to explain that one - with fewer moving parts how do you come up with less "parasitic loss" and "other reasons"?

[T-Bird]

there is less in OHC than Pushrod because with the pushrod the energy is forced upward then across and back down again with the OHC the Camshaft pushes down on the valves essentially eleminating alot of travel and energy loss and other reasons like they are easier to adjust for timing in most cases and the whole VVT thing that many companies are starting to use.

[RC45]

Originally Posted by T-Bird there is less in OHC than Pushrod because with the pushrod the energy is forced upward then across and back down again with the OHC the Camshaft pushes down on the valves essentially eleminating alot of travel and energy loss and other reasons like they are easier to adjust for timing in most cases and the whole VVT thing that many companies are starting to use.

Kinda vague answer there..

Cost and weight appear to beat down any OHC arguments these days...

[nthfinity]

in retrospect of T bird's argument, it seems the pushrod doesnt have massive torrential and plastic bending characteristics under normal---> extreme uses... so in phisics, it would only truly negate added inertial movment, and friction creating some heat. that cirtainly isnt very much on the down side.... or even at all...

[SilverPhoenix]

Originally Posted by T-Bird there is less in OHC than Pushrod because with the pushrod the energy is forced upward then across and back down again with the OHC the Camshaft pushes down on the valves essentially eleminating alot of travel and energy loss and other reasons like they are easier to adjust for timing in most cases and the whole VVT thing that many companies are starting to use.

Its not the force of the pushrods that makes the power lol, it does its job just as well as OHC, and take aprox the same HP to push the Valves down lol. And some OHC engines use small Pushrods to push the valves down.