I think that how long it takes to catch fire is in the order of a couple of milli seconds but i would have to do some calculation on that but it varies with fuel it is called ignition delay.

I meant how long do you have to 'crank' it before it starts running and reaches normal RPM. Also, how long does it take to reach normal working temperature?

If you can download that PDF file i pointed to it make some intresting reading.

Just finishing the dowload (ordinary dial-up line... )