"as an engine becomes less square the piston speed increases, as do the loads placed on hte engine components... and vica versa"


This is not true.
What the hell does "Less Square" mean?
Less square can mean that the cylinders are a GREAT deal larger or a GREAT deal smaller than stroke. Both are "LESS SQUARE".

And the size of the cylinders has no effect on piston acceleration.

The cranks' stroke inversly affects the rod length you can fit in the block, and that ALONE os what effects the piston speeds.
And to further develop this, Generally, the longer the rod, the higher an engive can rev.
The Late Smikey Yunnik was a great believer of long rods in drag engines. Longer dwell at TDC combined with appropriate cylinder head porting makes for increased torque (even though it wont be over a broad rpm range)

 

so was that a yes or a no?

t..

 

Rod Ratio is the building block on which every engines internal geometry is developed, and for which application it will be used for, but this has already been said.

Personally I am in favor of r/s ratio, but not to an extreme, to me r/s is used, as a tuning tool. The amount of thime that the engine can complete a burn greatly influences what rod ratio a particular application likes. Sustained burn time and pressure generated by the burn corrolates with piston speed. Sideloading (or lack there of) is nice, I haven't met anyone yet that likes shoving a rod out the side of the block. But sideloading should not get in the way of making power, that is why piston speed needed per application is the more dictative force placed upon the rod ratio that the motor needs to have.

 

sorry,

should i have said:

as an engine becomes under square the piston speed increases, as do the loads placed on hte engine components... and vica versa

my mistake
--
so, to help me understand, will engines with the same size rod and crank with different piston sizes have the same piston speeds?

what about the piston acceleration?

t..



[Modified by tinkerbell, 6:21 PM 9/16/2002]

 

'nother kickarse thread :D
stan

 

I see what you're asking and that seems like an interesting question. Let me see if I'm thinking on the same page here-
You're asking- since piston speed is calculated by the stroke and RPM, would a larger mass(bigger piston) with the same stroke affect the actual acceleration and piston speed? Seeing as a larger mass may take more work to accelerate, and in turn possibly affect the speed.
I would think so but I have no idea how to figure that out mathematically- some wanna help me out here?

 

Speed is independant of mass.

Speed = distance covered over time

 

Yes, but thats what I'm asking, could a larger mass slow down acceleration? And in turn take more time to cover a distance. Or is the increase in bore and the relative increase in power with that bore proportional to the smaller bore. In other words it is using the increase in power to use the same work to push the larger piston, so the acceleration and speed stay the same. Or am I *** backwards on my thoughts here It's ok, tell me if I am completely wrong, I'm trying to understand.