|
rockers and lifters receive the most punishment. Needle bearings are designed to rotate while revolving around the axis. This insures adequate lubrication and good wear characteristics. In the case of rockers this does not happen efficiently. Add to that harsh cam profiles you now have the lifter chasing the cam lobes, every time they loose each other it's like a little hammer on the bearings so you can increase seat pressure but now you face pushrod flex, more load on the bearings and spring fatigue. You also have the chance of a lifter turning in the bore, even the slightest possible amount cause bearing fatigue and can cause premature lifter failure. Then, with a hydraulic lifter the chances of the above happening is even greater because of the limitations of the lifter itself. When you run near/at or slightly above redline what do you expect. lol
|