No, that white plastic ring is designed to keep the engine from compressing the tensioner. The deal is that they did not have them at first and they figured out that if you parked a stick shift car on a hill, left it in gear and did not set the e-brake that the force of the car would transmit energy right throught the drivetrain, through the clutch, to the engine, and cause it to roll the engine backwards enough to compress the tensioner, then when you twist the key, WHAMMY!!! all hell breaks loose. Cool huh!?!?!?

Mark