I'm creating a 4-cylinder engine based on General Motors 2.5L engine made from 1977 to 1993.The firing order is 1-3-4-2. I don't know if the engine rotates clockwise or anti-clockwise. The timing gears mesh with each other instead of using belts or chains. How do I design camshaft for 4-cylinder engine? I have Autodesk Inventor.