Hello . There is a way, but it is a bit complex if you don't have the useful. I explain you.
The complicated thing is to peel the crankshaft, you need a useful that puts it in the front of the block and hesos the piston 1 in PMS. Even so, you can be wrong and lock the useful in the holes that are balanced with the crankshaft (it has happened to me). If your megane is one of the old ones, which I think, the crankshaft pinion has a key, so it will not turn when you take the pulley and you can mark it.
The crankshaft are hesitated by the user, the camshaft by a small mark on the extrior side of the pulley, in one of its teeth; And the bomb has another equal mark on its pulley. I am responsible for remembering that the crankshaft piñon has another equal brand, but I'm not sure.
Well, some distribution straps, the original has it and the gates also seem to me, they have three white stripes in different sections of it. These marks coincide with the brands of the cam, pump and crankshaft, so they serve you for the draft.
The problem is that thanks to this system you can peel the pump and the tree, but the crankshaft, if it does not have that brand, you must use the user of the block.
But I tell you that if it has no brand, but it does have a key (the crankshaft), the PMS is left with the key marking down and slightly with the tip to the left. So the pump and the tree are hesitated by the brands of the belt and the crankshaft in the form described above in the event that it has a key. If it is not of a key, but of crazy pineapple, you should use the useful.
I hope I have helped you. I know it is liado. In case of doubt again and help you. Chaoo