Sorry my post was not complete enough - what I meant was that if you have two equally good candidates, but one happens to have experience in Rails, that person is going to perform the coding test more quickly than the other candidate i.e. get a more complete / correct solution in a given amount of time. So I hope in this situation there are no time limits?
I never want to have time limits in these tests. Generally I prefer to tell the candidate "This isn't timed and we don't care how long it takes you. It tends to take x hours (where x better be less than 4) and most candidates get back to us in a week or so. If you can't do that, its completely fine, let us know when you anticipate having it done. This is just so we can judge where you are in the pipeline."
