The cams in our motors run on solid blocks, to adjust the valves you have to insert spacers to achieve the correct adjustment. So basically we have a solid lift motor which are noisy. To keep the noise down they put like a sprocket on the end of the cam. To put preload on the cam you twist the sprocket and take one of the bolts that holds the coil packs on and slip that into the holes that will align when the sprocket is turned. The bolt will hold everything in place. Install the cam and remove the bolt, preload set! This tension keeps the cams quiet.