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Twin Tank 

Oil Conversions

2Toc How It Works Image

How the 2Toc System Works.​

How Can a Diesel Engine Run Veg oil?

       When oils are heated they become less viscous. Cooking oil being a good example, where when heated sufficiently, can flow and combust quite like diesel fuel, thus being a great candidate for fuelling a diesel vehicle. However since diesel engines are not designed to run on a thick fuel such as veg oil, some modifications are required. The most important one; overcoming the problem of starting with a cold engine with cold oil being present in the all; injectors, injector pump, fuel filter, fuel lines and fuel tank. A few methods to overcome premature failure of these components or a non-start include the following, each method having its advantages and disadvantages:


     1) thinning the oil down by running on a mix of oil/diesel or Bio-diesel,


              2) converting the engine to a “Single-Tank” system allowing a cold oil start,


                         3) A “Twin-Tank” system, starting on diesel and switching to veg oil when warm


Why The 2Toc (Two-Tank) System?

       The Two-Tank oil conversion kit system has been proved to be the most reliable method of running diesel engines on veg oil. I also personally much prefer the safe running of a Two-Tank system installation, simply because it takes the stress and strain out of the already high wearing cold starts, thus preventing premature engine damage whilst waiting for the engine to reach its operating temperature. Without letting the engine and fuel warm up can cause premature damage due to over-loading the starter motor and battery from extensive cranking, increased stress on the injectors and pump from having to work with the thick oil (approx. 5 x thicker than diesel) and increased engine wear from poor fuel atomisation before the combustion chamber has time to warm up. When fuel does not atomise properly, un-burnt fuel molecules can occur within the combustion chamber causing possible polymerization on the piston bores and cross contamination can occur with the engine oil more rapidly, as well sending un-burnt fuel molecules out of the exhaust, having an adverse effect upon your engine and the  environment.

Which Engines Are Best For Converting?


       Unfortunately not all diesel engines are advisable for an oil conversion kit to run on veg oil due to some particular sensitive components or modern electronic sensors, tight tolerances, high running pressures etc. Generally the older the vehicle the more likely it can quite happily be converted and run on veg oil. From experience, vehicles pre 2000 are generally the better candidates for conversions, but by all means this does not mean that many post 2000 car cannot be converted, it just may require extra components and a more extensive fitting procedure and driving awareness. In most cases for Bosch inline and rotary injection pumps, along with their replica counterparts; Nippon Denso, Doowon, Diesel Kiki, Zexel etc and less so but not ruled out the Lucas/CAV pump a more simple 2Toc kit can be installed. See kits in 2Toc shop. We generally try to avoid HDi's and CDi's but have found the german PD's to be very good on veg however the kit is more complex incurring further costs, usually calculated on assessing of vehicle.

How the 2Toc Kit Works...

      Take a look at the schematic diagram; right, to see how the 2Toc Two-Tank WVO conversion system functions. A diesel tank, generally a small boot fitted one, is used to start and run the vehicle as normal from cold until the engine and veg oil is at operating temperature. The system then switches to the second veg oil tank, usually the original fuel tank, to begin feeding in veg oil for the entire journey and then just before arrival it is switched back to the diesel tank where the engine and fuel lines are flushed through to prime it up ready for the next cold start. Should the vehicle be left for only a few hours there is no need to flush the fuel system as the residual engine heat will be adequate to start up again on veg oil. The 2Toc kit can happily run on just Diesel, should veg oil supplies run low.


For more infomation on filtering your own waste veg oil check out

Filling car with Veg Oil Conversion 2Toc
Peugeot 306 Oil Conversion Engine Image
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