Optimal Valve Lash

One thing I learned by working with a cam designer is that the lash value is determined by the ramp design. So the lash is determined by the ramp that the designer uses. I also found out that the lash spec depends on the rocker arm ratio. So if you have a cam that is speced at 0.020 lash with 1.50 rocker arms then you need to open it up to 0.023 if you put 1.70 rocker arms on there. I didn't know that before.