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.
Abusive driving (neutral drops, hard launches, burn-outs, etc.) can also cause motor mounts to break prematurely. Motor mounts should last longer than that. They normally break when you put a lot of stress on them, such as hitting a raised railroad crossing going too fast.