Well the cold weather is here and pre-filtering oil is proving to be challenging. First let’s synchronize our terminology. “Pre-filtering” is the filtering of the waste veg oil before putting in the car’s fuel tank. My setup is a plastic 55-gallon drum with two small openings on the top. Suspended in one of the holes there is a large sock filter made of silkscreen fabric. The filter holds approximately 10 gallons of oil.
In the summer when daytime temperatures in my area are routinely in the 90s, I could filter 40 gallons of oil in 15 minutes or so. The oil would pass through the filter almost as fast as I poured in the oil. Now, overnight temperatures dip below freezing and daytime temps are in the 40s and 50s. The oil got hung up, even in a new filter. What to do?
There are a couple of solutions that I have become familiar with through discussions with other greasers. The first is putting an immersion heater in the barrel and the second is putting the entire filtering setup in a heated space.
Currently I am using solution two. It is working moderately well. I have the temperature set at around 68 degrees and the oil is slowly passing through the filter. I don’t like this solution however because I am using a good deal of propane to heat the space. This somewhat defeats (or at least dilutes) the purpose of using WVO in the car.
I have searched for a good design (or already manufactured)immersion heater and haven’t found one. I want a heater with a thermostat that will allow me to walk away from the barrel confident that it won’t heat up to 100+degrees. There is a nice looking heater for sale at Greasel.com ($48.50) but it has no thermostat and will heat the oil to 160 degrees.
The good news in all of this is that the car is starting beautifully. This morning it was 35 degrees and there was a layer of frost all over the car. As I have a single tank conversion, I have been warned that I may have to mix some diesel/biodiesel with my WVO to get through the winter.