Method for valvetrain lash adjustment with extra lost motion stroke and high stiffness lost motion spring

A method for setting lash on a rocker arm assembly having a lost motion stroke, the method comprising:

• providing the rocker arm assembly comprising a rocker arm and a valve bridge, wherein the rocker arm comprises a first end, a bore defined at the first end, a lost motion shaft inside the bore and being configured to translate along the bore, a lost motion spring, an e-foot, and a second end disposed with an adjusting screw;
• the lost motion shaft comprises a proximal end, a central shaft portion, a collar, and a distal end;
• the proximal end of the lost motion shaft extends into the bore and is biased by the lost motion spring toward the valve bridge;
• the collar is located on the central shaft portion on the lost motion shaft and has a diameter larger than the central shaft portion;
• and the distal end extends outside the bore of the rocker arm and is disposed with the e-foot;
• inserting a feeler gage in an area on the central shaft portion between the collar and the rocker arm;
• compressing the lost motion spring by adjusting the adjusting screw and moving the collar and the rocker arm toward the feeler gage;
• and
• adjusting the adjusting screw until a desired lash is attained,
• wherein the valve bridge comprises a wall that inhibits insertion of the feeler gage between the valve bridge and the e-foot, and the wall comprises a front wall, a rear wall, and a side wall defining an opening opposite the side wall.