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Why Is a Timing Belt Important

Update:01-02-2017
Summary:

Timing belt are reinforced bands of rubber used to coor […]

Timing belt are reinforced bands of rubber used to coordinate the turnings of crankshafts and camshafts in internal combustion engines. Many timing belts have teeth which is as same as the gears of a specific engine design at inner surface. Timing belts play a vital role in keeping the valves and pistons working in a precise order. Each valve and piston combination must push down on the individual cams on a camshaft at just the right moment.
You can ask your mechanic for a help to replace the timing belt in your car. Timing belts keep the different parts of a car’s engine in sync with each other and on average should be replaced every 60,000 miles. Because of the infrequency of a timing belt change, it can be easy to overlook this vital service.

Disconnect the negative battery cable using a wrench or socket. Lay it out of the way but do not allow it to touch metal. You should loosen the pivot bolt to move the drive belt away, located at the 7 o'clock position just beside the alternator then loosening the upper adjustment bolt on the alternator bracket. Slide the alternator inward. Lift the drive belt off the pulleys.

Remove the crankshaft pulley bolts and slide the crankshaft pulley off. Remove the water pump pulley using a socket. Remove the timing belt covers using the appropriate-sized socket. Temporarily reinstall the crankshaft pulley. Turn the crankshaft clockwise until the timing marks are aligned. The lower timing mark is on the larger sprocket just above and to the right (when looking down at the engine) of the crankshaft sprocket. The dot on the sprocket must line up with the mark on the block at the 9 o'clock position. The camshaft timing mark is a dot on the camshaft sprocket and lines up with the mark on the head at the 12 o'clock position on the sprocket.

You still need to move away the crankshaft pulley. Loosen the timing belt tensioner nut then turn the tensioner counterclockwise, releasing tension on the timing belt. Lift the timing belt off of the sprockets.
Check the timing mark on the camshaft sprocket and make sure it is still at the 12 o'clock position. Install the timing belt, starting at the crankshaft pulley and the intermediate sprocket (the large sprocket to the upper right of the crankshaft pulley). Check both timing marks to ensure they are still aligned.
Reinstall the crankshaft pulley. Route the timing belt over the top of the camshaft sprocket then down behind the tensioner, keeping the belt tight on the non-tensioned side. Using the special tool, start turning the tensioner clockwise. At the same time, put your hand on the timing belt about one-third of the way above the intermittent pulley. Not until the timing belt only can be twisted through 90 degrees could you stop turning the tensioner. You are looking at the belt's vertical edge. Using your thumb and forefinger, twist the belt towards the horizontal position. If it goes more than 90 degrees, keep tightening the tensioner. If it goes less than 90 degrees, loosen the tensioner until the belt twists 90 degrees.

Tighten the tensioner bolt to 33 foot-pounds of torque. Turn the crankshaft counterclockwise two turns. Check the timing marks. They should be lined up. If not, remove the belt and reinstall. Check the timing belt tension again as discussed in Step 5. If the tension is incorrect, repeat Steps 5 and 6. Remove the crankshaft pulley.
Install the timing belt covers. Tighten the bolts to 7 foot-pounds of torque. Install the crankshaft pulley. Tighten the bolts to 15 foot-pounds of torque. Reinstall the rest of the parts in reverse order of removal. You would better put 15 foot-pounds to torque the water pump pulley bolts if you get to the water pump pulley.