Make your own Biodiesel Part 1

There are at least 3 ways to run a diesel engine on biofuel utilizing veggie oils, animal fats or both. All 3 are used with both fresh and used oils.

1. Use the oil just as it is-- typically called SVO fuel (straight veggie oil);

2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or mix it with a solvent, or with fuel;

3. Convert it to biodiesel.

The first 2 techniques sound simplest, however, as so often in life, it's not rather that easy.

1. Mixing it

Grease is much more thick (thicker) than either petro-diesel or biodiesel. The purpose of it or mixing it with other fuels is to decrease the viscosity to make it thinner so that it streams more easily through the fuel system into the combustion chamber.

If you're blending veg-oil with petroleum diesel or kerosene (exact same as # 1 diesel) you're still using fossilfuel-- cleaner than a lot of, but still unclean enough, many would state. Still, for every gallon of

grease you use, that's one gallon of fossil-fuel saved, and that much less climate-changing carbon in the environment.

People use numerous blends, ranging from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals just use it that method, start up and go, without pre-heating it (which makes veg-oil much thinner), or perhaps use pure grease without pre-heating it, which would make it much thinner.

You might get away with it with an older Mercedes 5-cylinder IDI diesel, which is a really difficult and tolerant motor-- it won't like it however you most likely won't kill it. Otherwise, it's not smart.

To do it properly you'll need what totals up to an SVO system with fuel pre-heating anyhow, preferably utilizing pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no requirement for the blends.

Blends with various solvents and/or with unleaded gas are "speculative at best", little or nothing is understood about their results on the combustion characteristics of the fuel or their long-term effects on the engine.

Higher viscosity is not the only problem with using vegetable oil as fuel. Veg-oil has different chemical properties and combustion characteristics from the petroleum diesel fuel for which diesel engines and their fuel systems are developed.

Diesel engines are high-tech devices with really accurate fuel requirements, especially the more modern-day, cleaner-burning diesels (see The TDI-SVO debate).

They are difficult however they'll only take so much abuse. There's no assurance of it, however using a blend of approximately 20% veg-oil of excellent quality is stated to be safe enough for older diesels, especially in summer.

Otherwise using veg-oil fuel needs either an expert SVO service or biodiesel. Mixes and blends are generally a poor compromise. But mixes do have a benefit in winter.

Similar to biodiesel, some kerosene or winterised petro-diesel fuel blended with straight grease lowers the temperature at which it begins to gel. (See Using biodiesel in winter) More about fuel mixing and blends.