Veggie VW
The Challenge
It all started in college, daydreaming in a thermal dynamics class. A straight vegetable oil bus for road-trips. As happens, it took a very good friend to forge ahead (with his 1983 E350 van) and 6 more years before I finally decided to make it a reality.
The Solution
Old cars are easy to work on, cheap to find parts, and not much investment lost if it all goes to pot. So I found an 1985 VW golf with 270,000 miles on it. It did not run.
- Rebuild on diesel. Hard to make compression with piston ring gaps nearing 3/4 of an inch! Amazing it got that far, especially being a diesel. Slightly larger bores, new pistons and rings. Back up to 38 HP
- Vegetable oil is to viscous to be used directly it needs to be pre-heated. So the system retained the diesel fuel system in its entirety, and using an old Ford dual tank switch added a veggie fuel system as well.
- A two stage approach was used for the heating. All heat was coming from the outlet of the engine coolant (195 F) and the oil needed to be around 180. The tank was pre-heated and also I built a cross-flow tube heat-exchanger as close to the hot water source as possible.
- Drove across the country. Biggest design flaw was that the fuel also lubricates the injection pump and I did not have enough extra flow to provide ample lubrication to the pump.
