Generally, timing belts are utilized for driving a camshaft in an internal combustion engine by interacting a rotation of a crank shaft with a rotation of a cam shaft. Such engine's may be severely damaged when timing belts are worn down by an unbalanced timing between an engine valve system and a piston system. Accordingly, it is essential that timing belts are replaced before they break and are no longer operable.
However, there is a drawback in the timing belts thus described in that the timing belts are shielded by a cover, making it difficult to check with the naked eye if they are worn. As a result, undamaged timing belts generally replaced at a prescribed period without, thereby incurring avoidable expenses. Also, the timing belts may break without any indication that the timing belts have been severely worn, thereby resulting in engine damage.