How can you find a diagram to set the timing belt for a Mazda protege 2000 twin cams?
My Chilton's manual for import cars (98-00) has some nice diagrams. I don't know about the Haynes manual, since I don't have that one for my car, although the one I have for my Ford van is really nice. So I'd start there. I'm actually working on my timing belt (2001 1.6L DOHC - according the manuals, 2000 & 2001 are pretty much the same), and we found that the diagram description is slightly off. There are two sets of notches in the camshaft gears, one set must be facing each other, the other facing down. When you rotate the crankshaft (with the belt on, of course), the gears should line up when the crankshaft is in time. Also, when replacing the timing belt (at least on my 2001), you will have to remove the engine torque mount on the passenger side to get the belt off & on. The specs say to torque those bolts down to 47-52 ft. lbs. when you put it back on. Figured that'd save you some frustration :) Hope this helps a little.
A 2000 Mazda Protege with 1.8 DOHC engine appears to be a "free-running" engine, meaning there is no valve/piston interference in case the timing belt broke. There is enough clearance between the valve and piston, even if the cam stops (i.e. the timing belt breaks) with the valve fully open. Therefore, the car will not be damaged if the timing belt broke.