WVO Conversion

Written by Ivan on 16/08/2009. Posted in Vehicle modifications

This vehicle has a 5.9 litre Cummins Turbo Diesel engine with 6 inline cylinders and 24 valves. The fuel injection system is electronically contolled and built by Bosch. These pictures document some of the many stages of the modification process required to enable the engine to run on Canola Oil which I collect from various pubs and resteraunts after it has been used to fry food.. The truck does a little over 29 miles to the gallon on this waste product.

The heat exchanger, mounted on the exhaust manifold to the left of the valve cover, draws coolant from the engine outflow to the cab heater. A ball valve is fitted on the cab side of the “T” to slightly restrict the flow into the cab with no noticable loss of cab heat. It hits -40 celsius here in the winter so , believe me, I would notice!

engine bay 2

On the rear bulkhead to the right are the four relays that control the entire system

engine bay 1

These are the solenoid operated changeover valves that switch the fuel supply from/to diesel/WVO and the return from/to diesel tank/WVO loop

changeover valves

This shows the heat exchanger mounted on the exhaust manifold wherein the temperature of the WVO is raised (by coolant heat) to bring the viscosity down to a thickness acceptable to the injection pump. In the foreground, mounted on a bracket across the battery, is the coolant heated WVO filter

heat exchanger 1

The high pressure (15 psi) 95 gallon per hour electric fuel pump which delivers the WVO from the tank in the rear box of the truck to the engine. The delivery line from the tank is on the left of the brass “T” with the looped return from the engine entering from the top of the”T”. This system ensures that the heated WVO is not returned to the tank but is recycled for greater efficiency


The coolant heated SVO tank pickup consists of a normal fuel pickup surrounded by a coiled tube containing coolant heated by the engine which flows into the right fitting and returns to the engine through the left one. The centre fitting is the fuel pickup while the unit to the left is the tank contents gauge sensor. An elbow is fitted in the threaded hole in the centre to take the return to tank line which is used when purging the fuel system of SVO. The tank which was recovered from a wrecked boat is made of stainless steel and holds 389 litres


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