Hi Paul how have you been? been a long time since i tuned one ,but you have to imagine the cam that lifts the push rod is oppisite to inlet or exhaust lobe on the cam,the injector lobe is a circle with a dip in it. so after it fires it holds the injector pin in the seat until ready to fire next time , when ready again it goes down in the dip and for that moment fuel gets forced in then as it comes back out the dip it injects the fuel , and if you torque it down in the dip as it comes back up no where for it to go bends the push rod [never ever bent one probably more good luck then management lol] i always did the injector before the valve set as the 60 inch pounds held the rocker shaft up taking any wear out then set the valves just my way of thinking on valve set clear as mud lol billy be a better word smith than me lol the lifter goes down in the dip because its not a flat tappet they are roller lifter
