There's no pivot. Picture a bucket with a stem rising up from the middle. Turn the bucket upside down and the stem touches the valve tip. Now place the cam directly above the bucket and you have a gap between the bucket tappet and the cam base circle. Make a bowl in the bottom face of the bucket(which now faces up) and place different size shims in it to adjust your gap. The bucket has a precision OD and rides up and down in a tappet bore.
95-97 2.0L Same size bucket tappets all around with no shims.
98-99.5 2.0L Bucket tappets with shims.
99.5-Present 2.0L Graded bucket tappet, no shim. i.e. the stem to upper surface distance is sized instead of sizing the shims.
Advantages:
1) Less reciprocating mass.
2) Allows more aggressive cam profiles not possible with "slow" hydrailic lifters.
3) Less parts count, easier packaging.
I'm sure there's more...Terry?
