More power to you Twister.
I'm attempting to lose weight now, 8 lbs so far. If you want to lose the belly fat, crunches alone won't do it. You have to hit the entire core - all the support muscles. Two exercises that helped me:
Bicycles crunches - with your hands behind your head crunch while simulating riding a bike and move your torso so that your right elbow touches your left knee and vica versa.
Reverse crunch - on a Roman chair work your back muscles. Use your back to move from a perpendicular to horizontal position.
WARNING, your back is going to be stiff if you've never done it before. Persevere and your belly will tighten with the added benefit of no more back aches.
Good luck, hope this helps.