How to set the IC or CI Engine Timing Gears without any timing mark of Crank shaft,Cam shaft,Fuel injection pump,Idler,balancer gear wheels?

By looking the camshaft position or the running mate mettod

By putting the piston at the top dead center (TDC) you can do that by removing the spark plug of cylinder No 1, put a long thin screw driver inside the cylinder or a welding electrode, and hold it firmly, rotate the camshaft pulley until the screwdriver or the welding electrode come up to the end and when it's just begins to go down stop rotating the crankshaft pulley and return rotate backwards the movement the piston travel's downward, keep in mind while rotating the CS don't forget to rotate the camshaft pulley too,. After that be sure to put the valves of the opposite cylinder ( No4 in 4 cylinder engine, or No 6 in 6 cyl eng, or No 8 on 8cyl eng) you should make the valves in rock position ( which means the time where the intake valve start opening and exhaust value at the end of closing period, at that point the cylinder No 1is at the end of pressure strock, now you can put on and I install the timing belt or gear . Then you have a synchronized timing mechanism.