[Steve C.]

This from a tech article. Lash Changes....

WARNING. This might seem like a small thing, but it can be a subtle alarm. Mechanical lifter engines use lash or clearance between the rocker arm and the valve and despite a common misconception, if everything is working properly warm engine lash clearance do not change. If the lash changes – something is moving. This is true for both flat and roller lifter camshafts. Generally, if the lash increases, this means something is wearing which has increased the clearance in the valvetrain. This can be a flat tappet lifter that is in the process of flattening a cam lobe or it could mean a bent pushrod or perhaps a fractured rocker arm. With roller lifters, a minor increase of 0.003 to 0.005-inch of lash could be a warning sign that the lifter’s roller bearings are failing. This is just about the only signal you’ll get that something is wrong before the bearings begin to disintegrate. When that happens, their exit is quickly followed by catastrophic engine damage as those little needle bearings use engine oil to transport them throughout the engine. If you’ve never experienced this – consider yourself lucky. Those tiny little roller bearings end up between the pistons and cylinder walls – which can cause serious cylinder wall scoring. Or, they can find their way into the oil pump and cause it to seize, which is never a good thing.



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