Technical Stuff
Filtering Setup also HERE
Engine set up for running on vegetable oil (waste or new)
First thing you must understand is the viscosity (how thin or thick it is) of the fuel to be used.
A Listerclone is designed to be run on diesel but as people are beginning to understand they can be run on vegetable oil especially the free kind from pubs, restaurants, takeaways etc etc. In order to run on vegetable oil the viscosity must be changed to match diesel. This is done by heating it up using the engines coolant via a heat exchanger as the coolant temperature is around 80 to 90oC. There are many different types of heat exchangers available. The easiest to make yourself is a pipe within a pipe as shown in the picture below made from off the shelf plumbing parts.
Then there are flat plate heat exchangers (FPHE) , the type that are fitted to combi boilers like in the pictures below
Each of these types will do fine but the FPHE types are better, the more plates the more the temperature of the vegetable oil rises. They keep cropping up on Ebay all the time.
By keeping the oil hot the injection pump will cope better not having to pump a high viscosity liquid which it wasn't designed for. Another reason is so the injector sprays the vegetable oil properly and that it combusts correctly otherwise your engine will start to carbon up .This produces more soot so your exhaust system will also have accumulations of the stuff which is really messy to clean. Soot will also be produced if the engine is run too cold or idling for long periods. Every now and then you should run on maximum load to clear all the rubbish out, ie "put your pedal to the metal".
Now we come to waste vegetable oil. It comes in many forms. The best to get is stuff that is liquid at room temperature or below preferably otherwise you'll have to have a totally heated vegoil fuel system which requires quite alot of work including a heated fuel tank but it can be done. You MUST filter it down to at least 10 micron rating (vehicle fuel filter rating). There are many methods of doing this and can be found out by visiting some of the vegoil discussion forums such as This one where you will find loads of information about filtering, vegoil fuel systems and dewatering. Also there are some pictures of HJ's filtration system Here If you don't get the water out of your waste oil it will eat your injection pump away gradually. The fuel is put under very high pressure and so the water in it expands and explodes causing erosion of the inner working parts. On a vehicle a replacement injection pump is very expensive whereas on a Listerclone it's not too expensive considering what you are getting out of the engine for free.
More later......