Genuine MazdaSpeed shim under bucket followers allow the fitment of a huge range of aftermarket camshaft sizes and act as a replacement for both the NAs Hydraulic lifters and the NBs solid lifters. The standard “shim over bucket” design has a tendency to pop out shims when using big cams or are running at high RPMs due to the cam lobe hitting one side of the disc and allowing the other side to pop up. The chance of shims popping up enough to fly out increases with high RPMs or when using larger cams. By using a shim under bucket design the cam lobe comes into contact with the bucket itself, while the shim to space the bucket properly is inside the bucket, eliminating the shim popping. Take a look at the diagram below to see shim poping in action.
After a fresh valve job, we recommend assembling the valvetrain and use stacked feeler gauges to measure the lash (the distance between the top of the lifter and lobe of her cam) of each lifter. We recommend using Supertech lash caps with these lifters, these can be found below.
Technical Specifications
HEIGHT | 26.88mm / 1.0582″ |
INNER DIAMETER | 27.99mm / 1.102″ |
OUTER DIAMETER | 29.96mm / 1.1795″ |
STEM DIAMETER | 5.98mm / .2355″ |
STEM TIP DIAMETER | 5.54mm / .218″ NOTE: THERE IS A STEP-DOWN FROM THE DIAMETER OF THE STEM TO THE BOTTOM 3.58mm OF THE TIP |
STEM TIP TO HEAD SURFACE | 15.553mm / .61225″ |
- Sold individually, 16 needed for a full head