One thing a person needs to consider is just what will be thier activity when they encounter a good resource. Take his forum for instance. It should be considered a great resource. So my suggestion would be to ask a couple of questions that pertain specifically to your query. There will likely be some good answers. You've stated a motor (rotary), or could it be an actuator (linear). Other than basic torque (thrust) and speed, what other specific characteristics are you looking for. For your valving, flow and method of actuation will be major topics.
Your library, or manufacturers technical publications are excellent reading materials, but don't overlook what could be available here.