USMC5811

iTrader: (2)

Could someone please enlighten me on how "stroking" a motor works? As far as the different crank sizes and how they affect the ci?

same goes for boring as well. What happens in this process, etc.

777

iTrader: (21)

Look Here

increasing the stroke increases the amount the piston will travel up and down (directly related to crank/rod size). Increasing the bore increasing the diameter of the piston/cylinder wall. Either of these will increase the volume of air per revolution of the engine.

USMC5811

iTrader: (2)

all that math is a bit out of my league....is one more beneficial than the other? for example if i bought a new LS2 block, and wanted to stroke it, what would a 4.000" get me as compared to a 4.125" ?

777

iTrader: (21)

A 4" stroke (larger crank) and a 4" bore (stock ls2 bore) yields a very common 402ci engine.

From what I've gathered a shorter stroke yields a higher safe rpm range.

That site actually has a calculator on it where you put number of cylinders, bore, and stroke to get your cubic inches. Just set the drop down menu next to where you enter the numbers to inches.

usafws6

iTrader: (10)

Big bore short stroke is for rpm and long stroke is for torque and low end. Although this mainly applies to older small/big block engines. Reciprocating mass and valvetrain weight also play a part in an engines ability to rev quickly and safely.