Definition of quantal. 1  1 [Latin quanti how many, plural of quantus] : of, relating to, or having only two experimental alternatives (such as dead or alive, all or none) 2  2 [quantum] : of or relating to a quantum.
3. Engine movement. Another symptom of bad or failing engine mounts is an engine that moves in the engine bay. If the engine mounts are in good condition, they should be able to secure the engine firmly in the engine bay.
For this to happen, the spring's tension must be great enough to allow the lifter to follow the contour of the cam lobe, at idle and all the way through maximum RPM, for literally millions of cycles. If spring tension is too light, valve float and eventual engine damage can occur. If the spring is too stiff, friction-related horsepower loss and accelerated valve train wear will result. According to cam experts, one of the most common causes of premature camshaft failure is the use of improper valve springs.