Example

The fuel system in the Tarago operates as follows.  The fuel is drawn from the tank through a 19mm tube up to the heated coalescent filter.  This large bore fuel line allows the pump to pull cold lumpy oil during the winter months when the whole tank of fuel can be down below 10°c.

The oil is heated by the heat exchanger in the head of the processor, thinning it before going to the filters.  The water is filtered out of the fuel, and then passes through a standard particulate filter.  It is drawn through the filters by a facet fuel pump - the fuel processor should be on the vacuum side of the pump. The fuel then passes a temperature gauge ($14 at Kmart) which shows the fuel temperature after the heat exchanger up at the dash.   

When the engine is at operating temperature, the operator flicks a switch on the dash to turn on a 16amp fuel heater.  After a minute or so, the fuel can be switched to heated oil, which switches the fuel uptake and fuel return lines on the six way valve from diesel to vegetable oil. The 16amp heater will turn of automatically when the fuel reaches 90°c and back on if it drops below 75°c, thereby using less power as the coolant heats the fuel.

The total cost for the Tarago conversion if purchasing the parts from me and the wreckers would have been approximately as follows:
Tank                     $100    (Wreckers)
Fuel Lines & fittings         $50    (Auto Store)
Coalescent Filter             $400    (Vegiecars)
Particulate Filter            $40    (Wreckers)
Fuel Pump                 $12    (Wreckers)
Fuel Temperature Gauge    $14    (K-Mart)
16amp 12v Fuel Heater        $220    (Vegiecars)
6 Way Fuel Valve        $160    (Vegiecars)
Total                 $996 plus labour

As you can see from the illustration opposite, there is not a lot of room under the bonnet.  The coalescent filter is 420mm deep, so we had to move everything around just to fit it in.  The diesel filter is tucked away under the air filter hose, and the coolant overflow has also been moved.

The Nissan Patrol was originally set up with a 12mm line from the fuel tank, lagged with a 6mm fuel return, and coolant hoses.  This warmed fuel then went through the particle filter and to a 32amp 12volt inline fuel heater which brought the temperature to over 70°c.  The fuel then continued onto the 6 way fuel valve. There was no fuel processor or fuel temperature gauge, and no guarantee that the fuel would still be hot at the injectors.

The original “kit” for the Nissan, not including a fuel tank and coolant hoses, cost me around A$550, but I could now supply a similar improved kit for A$450.

Neither of these methods were the cheapest way of doing things, but the Tarago’s system was the most reliable and foolproof of the two.

The Patrol now has the same lagged fuel lines with a Facet Posi-flow lift pump at each of the tanks, and Delphi coalescing water and particulate fuel filters, with Vegiecars 12volt filter warmers fitted.  The fuel travels to the 6 way valve before being heated by a Vegiecars 16amp fuel warmer just prior to the Injection Pump (IP).  From the IP, the injector lines are heated again with the Vegiecars Cold Start Kit just prior to the injectors.

You could easily get away with the following if you are using an external method of removing the water, and making your own heat exchanger as outlined further on.

Plastic Tank -                 $25    (Auto Store)
Fuel Lines & fittings-             $50    (Auto Store)
Particulate Filter                $40    (Wreckers)
6 Way Fuel Valve            $160    (Vegiecars)
Total                     $275    plus labour

The fuel must be heated to around 70C before it will burn properly.  It is important to remember to switch back at the end of your trip and purge the system of vegetable oil because the fuel lines can block up if they get cold and the vehicle can be very difficult, if not impossible, to start. 

A safe guard would be to  install a buzzer which sounds when the operator turns off the ignition without switching back, to remind the operator to bleed the fuel lines back to diesel.  An alternative to the buzzer is to install a turbo timer that switches the fuel back to diesel and then runs for a set period of time. (see Switching Control)

Many people operating on vegetable oil, have noted that the fuel is hot before the injector pump (IP), but tends to be cooler by the time it reaches the injectors.  One customer had the fuel at 90°c before the IP, but found that it was only at 40°c by the time it reached the injectors.  As a result his vehicle was not idling properly and was billowing smoke out the back.

You may find that it is necessary to insulate your fuel lines to avoid heat loss either through a cooler atmosphere, or in his case air cooling from the wind blowing through the engine bay.

We at Vegiecars have developed a (patent pending) “Cold Start Kit” fuel injector line heating system.  This system incorporates a series of heating elements wound around the injector lines just before the injectors that are thermostatically controlled and assist to ensure that the fuel is at the appropriate temperature before the injector nozzle.

This kit includes thermal insulation and a dash mounted thermometer so that you can monitor the temperature of the system.  I have been running this system in the Nissan Patrol for months now, and find that it offers extremely fast switch over time as well as a much cleaner burn and less injector noise. 

The kit also allows you to preheat your injector lines if you have forgotten to purge the system of vegetable oil.  I would recommend that this kit be incorporated into any system that you might be proposing.