How to swap heads quickly.

[iceminion]

Originally Posted by niterydr

Its actually a hydraulic rod that provides tension over the length of a typical belt cycle/revolution. If the tension is not correct to begin with (on the pully/tensoner rod not centered) it is very likely that the tensioner will eventually run out of range and not compensate on during a high rpm condition, or start-up/shut-down stress.

Correct, an auto adjusting tensioner.