Posted by clueless [201.202.29.210] on Friday, April 19, 2013 at 09:46:55 :
In Reply to: thelength of the rods does not change the cubic inches , posted by Bruce in BC [24.207.115.172] on Thursday, April 18, 2013 at 15:46:04 :
The object of using the longer rods is to change the duration of the piston at tdc and bdc, this allows the crank to be further into the rotation before the charge fires.
hottrodders op
Hello Hudson: Long rods are a definite advantage. But I think a lot of people don't understand why. And I don't understand that 1.75 ratio being the ideal, I tend to think the longer the better. My thinking on the rod lenght is that the longer the rod, the better the angle you have while trying to push the crank down (some kind of physics thing). Along these lines, this is why moving the piston pin over in the direction of rotation helps power because when you do this you get a better (less) angle on the rod to crank. I think many older engines had the pins offset the other way to quiet down piston knock (rattling). And these engines, if they got flat top or symetrical domes,could be reversed in the bores to offset the pins in the power gaining position.
Frank