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Bio Your Engine


Many of you out there will be searching for cleaner ways to power your vehicles. Perhaps you’ve found a good source of waste veggie oil – and someone to process it – or maybe you’re even growing your own crops to cold press for fuel. Perhaps, like me, you’re doing neither but want to wean yourself off fossil fuels and suck up some bio-diesel instead. So what are the options for the South Westerly diesel driver?

If you own a diesel vehicle you can either convert your engine to run on pure veggie oil (rape seed oil is the best) or you can forget the conversion and buy specially prepared biodiesel to pour straight into your tank. (Always check with your manfacturer that your car/van/truck can run on biodiesel – ed).

Biodiesel is made from waste veggie oil, making it cheaper than ordinary diesel and carbon neutral. I looked into sourcing it in the South West, and discovered that within spitting distance of my floating home, is a supplier. Biosulis produce biodiesel that I can put straight into my engine as a good alternative to my regular boat-yard diesel. The bio-fuel is made from recycled waste oil collected from local chip shops and restaurants and is available straight from their pump at the processing plant in Radstock. At 91p per litre, you really can’t argue with this. What’s more, if you take usable waste oil with you for them to process, there’s a litre discount of 5p.

So I ask myself… how do you make a litre of waste chip oil into a litre of fuel for any diesel engine? Why are people getting engine conversions to run on pure vegetable oil, when it’s so simple to fill up on bio-fuel? And so to the facts. Pure vegetable oil is too thick to run in a normal diesel engine. Which means that in order to use it as a fuel source, you’ve either got to thin it down, by removing some of the glycerine (as done at Biosulis, resulting in a useful by-product – soap!), or you have to heat it up, by making some modifications to your engine.

There are two main types of engine conversion. The two-tank conversion involves running with one tank of normal diesel and one of veg oil. You use the regular diesel to start up, warm up and shut down the engine. Once the engine is warm from the mineral diesel, you swap the fuel source over to veg oil, which is also now warm and runny, and perfect for fuelling that engine.

The other type of conversion is commonly known as an Elsbett after its German manufacturer. The original Elsbett conversion involves changing the injection pump, glow plugs, electric pre-heating element, electric control relays and adding an aluminium plate heat exchanger in your engine. The basic result of this is to preheat the vegetable oil before ignition and change the way the fuel is sprayed into the engine, to deal with the thickness of the oil.

Conversions are more costly (£500-£1000 for a kit on the internet or £1500-2000 for installation by reputable eco-mechanics), but once done, they allow you to run on pure veg oil from whatever source you choose (be that Lidls or your local organic farmer’s market). If you are planning to hold on to your motor for a year or two, in the long run, you will save a packet in fuel costs.

When buying veg oil to put in a converted engine, you are obliged to make a Duty Return to the Customs & Excise at a rate of 50p per litre. If you make your own biodiesel for personal use, you get a tax-free personal allowance of up to 2,500 litres (or 25,000 miles in a car) every year, as long as you can prove your fuel is decent quality. After that, you must pay 50p tax per litre of fuel produced. If you buy biodiesel at the pump, it’s the producer who pays the tax, at a rate of 28.3p per litre.

While biodiesel producers hark the benefits of recycling waste chip fat, engine converters emphasise chemical-free production, fuel autonomy and decentralisation in production, processing and use. I wonder who’s gonna get to eco-heaven first…

Hmmm now let me see… Biosulis run their processor on their own generator, running on their own fuels. Carbon-neutral they say. Recycled fat – I like it. Bio-Power in Plymouth, also selling recycled chip oil biofuel (88p per litre) say they cannot get enough of the stuff. In fact used fat dealers (is that the right word?) are exporting our British chip oil to Europe where biofuel processors will pay more on the litre (as they have no tax to pay). ‘Cold-presses everywhere’ is the message from Matt at Brighton-based Blooming Futures… “In Germany everybody’s doing it. There are over 400 presses and the environmental footprint is next to nothing,” he says.

Biosulis, Radstock 01761 411011,

Plymouth Biofuels Ltd, 01286 830312,

Blooming Futures (Brighton-based conversions with strong DIY ethic):

West Wales conversions:

Listings of biodiesel suppliers across the UK:

Schnews How To article:

How To site (veg oil & vehicle conversion):

Book: “From the Fryer to the Fuel Tank: The Complete Guide to Using Vegetable Oil as an Alternative Fuel” by Joshua Tickell.


First published issue 48 (Spring 2007)
Written by Kate Burrell



Disclaimer – details were correct at time of going to press, but may now have changed. Please make your own checks.

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