Cheers for the info. Randomly my mates decided to convert his fiesta to run on veg oil. Ordered a small second tank, 3 way valve and pre-heater.
No need to convert a festa, the wife's Fiesta runs better on svo than on derv.
I ran my previous car (toyota) on veggie for years, but with our local branch of Macro shutting down and the supermarket price not being great at the mo (and Tesco nazi-ing the supply to 3 offers per customer) I just can't be arsed anymore.
Unless you can get wvo free or cheap, it's not really worth the bother. Any idea how long it takes to fill a disco with 3ltr bottles of oil!? Bloody ages.
Used wvo, if previously used to cook fatty meat products (hmmm...fatty meat products..) can also cause problems with build ups (I forget what they are called) that are apparently like a glassy film that will reduce engine efficiency, these oils are best treated and turned in to biodiesel as the fatty acids are removed or converted (again, I forget) during the process. It's all very simple if you are a chemistry genius, I'm sure. It's something to do with long and short chain hydrocarbons.
If you search ebay for B100 biodiesel, there are a few guys who sell it at around 80-90p/ltr. It's a lot less messing around than getting your driveway covered in oil stains, having the space to filter and store it (if it's wvo) and there is less chance of going out to the car on a winter morning and flattening your battery trying to get started (been there-curses!). There's nothing like that lumpy running that puts the fear of god in to you as you wait that you will hit operating temp before joining the M6.
Unleaded is the best (legal) thinner. You can also use kerosene (don't know where you get that from) and white spirit, but I found that changed the smell from donut shop to sewer. Might have just been me though.
For those worried about using unleaded in your oil mix: Truckers in colder climates and even here used to add a 'slug' (technical term I'm told) to keep the fuel viscosity down. But now derv is used more widely it is winterised by the manufacturers. A smidge of petrol in the old tank now and again will also clean your fuel system, I'm not sure how true that is though-most of the fuel system cleaning additves are mostly petrol derivertives anyway.