The Mazda 1.6 and the 1.8 engines have the same timing belt replacement procedures. They are considered free-wheeling engines - the possibility of engine damage in the event of a belt failure is minimal. This is probably one of the easier timing belt replacements you can do. Mazda recommends that the belt be replaced at 60,000 miles the first time, then every 90,000 miles thereafter. This article assumes that the reader has a basic knowledge of mechanics.
Remove the air intake pipe, cam and crankshaft sensors, radiator hose and accessory belts.
Remove the water pump pulley and the crankshaft pulley bolts along with the plate behind the bolts, and then remove all three of the timing belt covers.
Turn the engine by the crank bolt until you have top dead center. The crankshaft has a mark on the block at 12 o’clock in the form of a ‘v’ and a notch in the pulley. Align these marks straight up. The camshaft pulleys also have notches or lines. When properly aligned the right pulley will have its notch at 7 o’clock, and it will be lined up to a raised mark on the block. The left side will line up with its mark at 5 o’clock.
Remove the crankshaft sprocket bolt and the crank pulley boss behind it. Make sure that you did not turn the crank when you removed the bolt. The marks should still be aligned. Loosen the tensioner bolt and move the tensioner away from the belt and loosely tighten the bolt to keep it away from the belt and out of the way.
Remove the timing belt. Install the new timing belt – keep in mind that the object is to keep the belt tight on the right side - opposite of the tensioner. Start at the crank and pinch it with your fingers so it doesn’t move and take the belt up and inside of the idler pulley and over the right cam sprocket, then over the left cam sprocket, then inside the tensioner. At this point, using your left hand, push in slightly on the belt where the tensioner is. Loosen the tensioner bolt and let the tensioner snap against the belt. Slightly tighten the tensioner bolt.
Turn the crank two revolutions and make sure the alignment marks are still lined up. Loosen the tensioner bolt and let it take up the rest of the slack. When it is tight enough, the belt should have no more than a slight deflection – no more than .40 inch - at the top between the cam sprockets when you put pressure on the belt. If you get it too tight it will sing (make a loud whining noise), and if it’s too loose, it will come off.
Turn the engine two more times and check alignment marks. If they are still lined up, replaced the rest of the parts in the opposite order that you took them off. Remember that the crank sensor should have an air gap between 0.20 and 0.59. The crankshaft bolt gets 122 ft. pounds of torque.
