waste veg oil... how do i use it as diesel?

[HyLuxx]

Is advise still running on here? I would like to connect

[budweiser]

As far it's filtered to a degree, some dilute it to a percentage, some use it straight in,
I have seen some have a preheat system,
It would smell like a fish and chips shop

[jameswhitfield]

Since this thread is active again, there is something worth adding on the tax side. It is actually more straightforward than most expect.
HMRC allows up to 2,500 litres of vegetable oil per year for road use before you need to register or pay duty. That is under the small producer or user exemption in the biofuels notice. Just keep a rough record of what you use. The limit is per person, per year. If you go over, you have to register and pay duty on the whole amount. For a Surf driving average miles on a blend, you probably will not hit the threshold. Daily drivers running pure vegetable oil might get close.
As for engines, what has been said above matches my experience. Older diesels with indirect injection and mechanical pumps handle it best. The key is providing enough heat and good filtration. Cold veg oil is thick. Most people mix in some diesel during winter, or they add a heated fuel line. Change the fuel filter early on, as the oil tends to clean out old diesel deposits and the filter can clog up in the first few weeks.
And yes, it really does smell like a chip shop. Some of the guys at work say that is the main appeal.