My mistake and a thousand apologies Bolinhas. As Charlie and David C realized, I've been happily telling you all about the FIRE family of engines which have a timing belt when all along yours is nothing of the sort being as how it's the earlier family of engines which used a timing chain! I'm not so familiar with your engine, but I think your crankshaft pulley has just that one big nut in the middle and the pulley which is keyed to the crankshaft so can only be fitted in one position.
This "key" I refer to will be either a "parallel key" or a "woodruff key" (google it if you want to know more) If so, most of what I previously told you doesn't apply to your engine - again apologies! With the pulley in place on the engine you can't see it as the big bolt hides any possibility of seeing the end of the groove in the shaft/pulley. The "V" belt, as you'll know, drives the alternator and water pump and does not require to be timed (in fact, as it has no driving teeth, it can't be timed)
I think I can just see, as David C says above, the crankshaft sensor at the edge of the toothed segments on your pulley - beside the little drilled holes. As David C says these holes are drilled during manufacture to achieve a perfect balance of the pulley assembly and are of no interest to us when working on our cars. If you look at the segments (teeth?) on the outside of the pulley you'll find (I think) that there will be one bit where it seems to be "missing" a tooth? This is the timing reference point for the ECU to "know" what position the crankshaft is in so it can decide when to fire the spark plugs. So, of course, it's important that the pulley goes on just right for that missing tooth to be in the right angular position in relation to the crankshaft. On your engine it's the key which ensures this and on the FIRE engine it's the wee "pip" on the bottom timing sprocket and it's corresponding wee hole in the pulley. Whereas it's possible, if you're not paying attention, to put the FIRE one on "wrong" I think, because of the "key", your's will only go on in the one position (as long as the key hasn't fallen out of it's slot of course!
By the way, further to what I said above, you'll notice the "V" belt does have what appear to be "teeth" on the inside of the "V"? These are not truly to be considered as "teeth". They do not engage with a toothed drive wheel but are there to allow the belt to flex freely without cracking as it travels round the pulleys and then straightens out on the run to the next pulley. They are there to make the belt last for longer by reducing stretching and compressing stresses on it. "V" belts drive by "wedging" themselves into the "V" of their pulleys and transmit drive solely by friction on the sides of the "V" shape - So a "V" belt which is so worn that it can bottom out in the "V" of the pulley will never be able to satisfactorily transmit drive properly and should be renewed.
Hope that's helpful? and again sorry for my confusing post earlier.