V-belt might be worn by the inner portion of the CVT housing.

V-belt might be worn by the inner portion of the CVT housing

Matters needed to be attention when CVT transmission is modified

V-Belt might be worn by the inner portion of the CVT housing


For understand easily, the video will be presented in an exaggerated method, so it is for reference only.


When a vehicle is running at high speed, the V-belt come to the highest position. In this case, the running V-belt might have rubbed with the top position of the oil pan located under the lower position of CVT housing, and the problem of V-belt worn by the top oil pan or damage to the oil gasket might happen.

problem - V-belt have rubbed at high speeds


  • The range of the CVT shifting ratio becomes broader
    • The V-belt becomes moving further outward due to the structure of several parts being changed, for example, the surface angle becomes smaller, and the outside diameter of Variator becomes larger.
  • The space of CVT housing is not large enough for tuning parts.
    • When the vehicle is designed at the factory, the gap between the V-belt and the engine case becomes too small when the vehicle runs at high speed, and the elasticity of space needed for tuning is low.
  • Installation not right or errors
    • This kind of wrong installation may not cause problems in normal times, but combined with the problems of 1&2, it is not allowed to have any slightly wrong installation.
the surface angle becomes smaller
gap too small

How to improve?

Installing one 1 mm thickness of washer between the boss and the inner side of the fan, this purpose is to prevent the V-belt will rub against the CVT housing when the vehicle is at high speed and V-belt is drop down and lower.

How to improve - Installing one 1 mm thickness


Most vehicles do not have this problem, when the installation is completed, do not close the CVT housing immediately. It is recommended to actuate the accelerator to see if the V-belt will rub against the engine case at high speeds.

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