This is a view of the Pollack change over valve mounted at the front of the engine bay, just in front of the injector pump. The copper tube assembly is the end of the heat exchanger, the thin 8mm tube containing the Waste Vegetable Oil (WVO) from the second tank. This type of valve is essential to any WVO conversion due to the fact that two seperate fuel tanks are needed. This valve has the added advantage that it can switch between fuel tank contents senders, utilising the vehicles single fuel gauge. I found that there is no easy way to mount this valve as one set of pipes will always be in an awkward position relative to the others.
This is the modification required to be added to a second tank in order to heat the oil and make it less viscous. The perspex panel was installed to enable viewing for prototyping purposes. At this stage anything can go wrong!!! (A slight leak was fixed later.) The panel is hinged in case the WVO is more solid than expected so it can be "shovelled" in.
SECOND TANK "SHOE HORNED" IN THE BOOT. I think this picture speaks for itself. I was extremely lucky on ebay to get a tank that fitted like this one did. It holds an impressive 10 gallons.
It is now swathed in foil backed loft insulation which has proved to be brilliant in heat conservation. No small thing as this cuts down, if not eliminates "heating up time" when the vehicle is started up on normal diesel. The fuel reaches temperatures of 70 degrees + on a decent journey and is still around 50 degrees 12 hours later!
This image shows the rear (Tank) end of the heat exchanger, which is basically a tube within a tube, in this case an 8mm copper tube. Central heating micro bore available from Wickes, B & Q etc. , run inside Goodyear radiator hose. This warms up the waste oil in the hose and keeps it fluid, especially on cold mornings as any dormant WVO will remain in the pipe when left for a long period of time and congeal. Your injector pump would have a bit of trouble trying to suck semi-solid fat through this.
It only takes approx. 5 to 10 minutes for the WVO to become useable.
By the time this has been posted, any pipe work has been lagged. The temperature retention is very good so quick start ups within a few minutes are the norm. The smaller diameter tube teed off contains heater coolant which is fed through the radiator assembly inside the tank and returns back to the heater circuit through the tube visible in the background. The car seat backs are down to make this arrangement clearer. 15mm isolation valves have been used to facilitate easy tank removal. Just as well when dealing with a leak. The tank arrived fitted with a supply and return assemby which is also part of the sender unit. This is the reason the pipe work is up in the air, as I wasn't about to make work for myself drilling into the base of the tank and running new risks of dodgy, home made bulkhead connections.
PASSENGER SIDE exit from car interior to engine bay.
This was the most difficult part of the conversion, only by way of the fact that the hole cutter I had wasn't up to the job and I had to finish off the hole with a hacksaw blade! The upper tube is the heat exchanger and the lower, the return. Directly through this part of the bulkhead are the heater hoses and couldn't be better placed. Checking to see which heater hose heats up first when starting the engine, this determines the supply feed through the heat exchanger. The other hose will obviously be the return. Needless to say these tubes have been lagged with 22mm foam insulation as they get quite hot (as my wife will testify when it touched her foot). The tubing has been installed inside the car as this seems best, bearing in mind where I live. The farm track to our house is very uneven and any extra pipes under the car would be susceptible to damage. Also it keeps the car warm and reduces heat loss.
Once through the bulkhead, the heat exchanger (lower tube) containing the 8mm copper pipe is routed up to the Pollack valve with as wide a bend as possible. Again very fortunate to have the space to do this. The upper tube has been tapped off the heater supply hose, just visible at the rear of the engine bay. This has been taken up to the end of the heat exchanger as far as possible, to ensure that as much of the fuel supply pipe is shrouded in hot engine coolant as possible leading up to the change over valve, just out of site to the left of the picture.
The fermenting bin in the picture is fitted with two kettle elements. It was (and still is) instrumental in producing biodiesel. It proved to be excellent for heating up filtered waste oil and feeding it directly into the injector pump. It was obviously a success as this blog wouldn't exist if it wasn't! The rear car seats are visible in the background. They had to be removed to make way for the supply and return tubing which run through the rear seat base. To avoid serious pinching of the tubes, they had to be modified also. More hacksaw work!
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July, 2008