…no debt ceiling increase does not equal default.
That only happens when the treasury doesn’t make payments on the debt.
[Update 2013-10-04 19:20:55] Here is a good article explaining how the only way a default could really happen is if the Treasury refuses to prioritize spending. And here’s another. In short, it would be like someone who makes $100,000 per year declaring bankruptcy over a $7,000 credit card bill.