Hi is it a 1.2 16v? just changed the head gasket on mine and there is no timing marks. You have to set the pistons using fiat tools or 4 rods the same lenght till they are all the same height and locate the notches on the cam shafts.best to remove the alloy cap on the side of the head extention and the 2nd from right rear alloy cap.
You might want to do a compression test as you may have bent a valve? not much clearance in the head.