A simple calculator for working out how far a piston will move for a given number of degrees turn of a crankshaft. Originally put together out of curiosity; handy for folks that like to set timing using a DTI gauge or possibly just want to turn up a dead stop plug.

Measurements are in degrees and millimetres. Length 'L' is the distance between the centres of the big and little
ends (**not** the total length of the rod!). Crank radius is half of the stroke. Note that the calculation is only accurate for **non-offset** cranks, being based on
the triangle SCB in the diagram.

Changing any one of the three variables will update the distance from TDC.

mm | |||

mm | |||

deg. | |||