Quick venting question(s)

[revans]

I am in the process of making a semi-advanced combustion and just was wondering how necessary it is to be able to vent the chamber via a ball valve with a fan. I was planning to follow something like design on Pete Zaria's "Complete Plans" but I cannot find one of the large plastic ball valves that seem to be used cheaply. However I do have a brass 1/4" ball valve which I could thread into the end, this one here:
http://www.topmaq.co.nz/product_detail.aspx?id=AIAC6050
It seems to have quite a small ID though so would this provide enough airflow or is it not worth the effort?
Any answers or alternative suggestions are greatly appreciated. Cheers.

[MaxuS the 2nd]

You need to properly vent the chamber to allow fresh, unused oxygen in for the reaction to work well.
I don't think 1/4" would be enough. You could always build a 'Quick Vent' System that's been used a few times, and especially on Gort's combustions.