Im doing a valve adjustment on a newer Chevy with a 350 in it and ran into a problem (I think). Its a roller cam w/ hydraulic roller lifters. I did the adjustment like you normally would. Move the pushrod around until there is zero lash. Then tighten the nut on top of the rocker 360 degrees and they are set. On most of them when I did the 360 degree turn on the nut the spring in the lifter would compress like normal (and still can compress for a few more thousandths until the valve moves) and the valve would stay put. On a couple of them when I would tighten them the 360 degrees the actual valve would compress and not the spring in the lifter. Is this bad? Why is this? I made sure I'm adjusting the valves when the lifters are not on a lobe of the cam. I can visually tell the lifters are all the way down because the lower intake manifold is off. On every lifter the springs are completly extended and none are stuck down. Im re-using the old cam, lifters, pushrods since they are in good shape. I cleaned the lifters though and I think when I did this I cleaned the oil out of some. I think the ones that are still filled with oil wont allow the springs in the lifter to compress which is not a big deal once the engine is running? right? Im confused some can any help?