Having done the timing belt 2 or 3 times now (on the same engine!) here are some tips;
Hydraulic tensioner
Different to the 1.5 and 1.8 engines which have a spring tensioner. This is a sealed unit which expands as the belt wears, the unit is said to need replacing when doing a timing belt. However the Mazda manual says you can compress the tensioner in a press and reuse it! Saving you £60 on a new one.
You can of course do it in a vice like I did. There may only be one set of holes, use a 0.8mm pin to secure the tensioner until you fit it back on.
How to fit the belt
Reset the tensioner like above. Torque the tensioner to the block to 25Nm. Align the marks on the cam shaft pulleys and the crank puley as shown.
Starting at the crank, pull and fit the belt around the idler, then the front cam pulley, then the top idler, then the rear cam pulley, then the tensioner. Doing it this way ensures you get the timing right on all 3 pulleys first time and any slack is taken by the tensioner. Crank it twice around by hand. Check alignment on the 3 pulleys before releasing the tensioner pin.
If you struggle fitting a new belt
2 Things which may help. Heat the belt up to make it more elastic. Remove the rear cam pulley and slot the bolt in and tighten down to 122Nm (you may need to lock the cam shaft with a thick bar through the pulley wheel.
Main pulley bolt is 150Nm so eat some weetabix!
