A DAYCO 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. A6 (4B2, C5)
2. A6 Saloon (4B2, C5)
3. A6 / S6 (4B2, C5)
4. A6 Avant (4B5, C5)
5. A6 / S6 Avant (4B5, C5)
6. A4 (8E2, B6)
7. A4 / S4 (8E2, B6)
8. PASSAT (3B3)
9. PASSAT Saloon (3B3)
10. PASSAT Variant (3B6)
11. PASSAT Estate (3B6)
12. A4 Avant (8E5, B6)
13. A4 / S4 Avant (8E5, B6)
14. SUPERB I (3U4)
15. SUPERB I Saloon (3U4)
16. A4 Convertible (8H7, B6, 8HE, B7)
17. A4 / S4 Convertible (8H7, B6, 8HE, B7)
18. A4 (8EC, B7)
19. A4 Saloon (8EC, B7)
20. A4 / S4 (8EC, B7)
21. 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.