A SWAG brand Tensioner Pulley, timing belt is a part of the timing belt drive, which serves to bypass the belt in a certain place or several places and is a freely rotating pulley of small diameter.

The composition of the roller is small: it is the roller mount, the internal rolling bearing with a protective oil seal, and the working body of the roller itself, which is in contact with the belt.

1. 3 (E21)
2. 3 Saloon (E21)
3. 3 (E30)
4. 3 Saloon (E30)
5. 3 Touring (E30)
6. 5 (E12)
7. 5 Saloon (E12)
8. 5 (E28)
9. 5 Saloon (E28)
10. 5 (E34)
11. 5 Saloon (E34)
12. Z1 Roadster
13. 3 Convertible (E30)
14. See more in applications

The principles of the timing belt tensioner work

Excessive tension leads to intensive wear of the timing parts - pulley bearings (water pump, generator, tensioner, etc.), the belt itself, and others. In addition, a tight belt stretches faster and shortens its service life. Too little preload is fraught with more serious problems - slipping of the belt along the toothed pulleys of the camshafts, which leads to a violation of the valve timing and deterioration of the entire engine.

Therefore, a tensioning device is introduced into the timing drive in the form of rollers of one design or another, which, during engine operation, maintain an optimal belt tension.