Dave's Bus Conversion

Vegetable Oil Fuel


My MCI 102A3 bus can run on vegetable oil, also known as "SVO" (straight vegetable oil) or "WVO" (waste vegetable oil) or veggie oil or even vegoil. It has a Detroit Diesel 6V-92 Turbo engine, and I did the conversion myself.

It works like this:

  1. I stop by a restaurant that has a deep fryer (chinese restaurants for example). They need to pay to get rid of their waste oil, instead I take it off their hands for free.
  2. I pump the oil into a large (210 gal) "dirty" tank.
  3. Oil in the dirty tank is filtered and pumped into a "clean" (50 gal) tank as needed.
  4. SVO in the clean tank is sent to the engine.

veggie oil bus conversion diagram

How to convert a bus


The WVO conversion works and I've driven a couple thousand miles on WVO already, but there are a few things I'd do differently or investigate if I were to do this again.


WVO is a sticky process, figuratively and literally, and every once in a while it has it's problems. Here's my list of issues and resolutions.

Problem Issue Solution
Power loss Filter dirty Change filter. First bleed some oil off the bottom, then remove top, swap filter, make sure tabs don't get stuck and hand tighten.
Air in system Oil should overflow if top of filter comes off. If not:
  • Make sure filter bleed is closed
  • Make sure top is air-tight. Make sure filter tabs aren't getting stuck in the filter lip.
No Dirty->Clean Transfer Filter dirty See above
Filter body clogged Unlikely on Racor, as inlets/outlets are wide, but consider taking off bowl and cleaning
Intake screen clogged Pull up dirty tank intake (use a rope) and possibly clean off screen
Not Enough Heat Coolant flow restricted Check hoses for kinks, check valves for 'on'. Feel hoses for heat to find obstruction
"Least Resistance" Coolant may take path of least resistance. Notes:
  • Water pump is mechanical, so idle/fast idle isn't good enough to get coolant flow to oil tanks, so be sure to drive.
  • Turning off cabin heat doesn't seem to make much difference with getting heat to WVO
  • Use electric bucket heater as supplement?
  • Make sure restriction valves are properly set

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