Dave's Bus Conversion

Vegetable Oil Fuel

What?

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:

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.
I pump the oil into a large (210 gal) "dirty" tank.
Oil in the dirty tank is filtered and pumped into a "clean" (50 gal) tank as needed.
SVO in the clean tank is sent to the engine.

How to convert a bus

Conversion album showing directions for how to convert a bus/large rig to vegetable oil.
Parts list
FAQ - Frequently Asked Questions about running a bus on waste vegetable oil

Changes?

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.

Use different hose for coolant (fuel hose is expensive!)
More electric heat, maybe no coolant heating (and all the plumbing/hose/time/cost that goes with it?) Consider that the majority of installation time and money goes towards all the plumbing. Also that the bus has a massive 6.5 KW alternator that (at least in my case with the on-board A/C removed) is barely being used. Furthermore, electric heat could optionally use the house electric system and could heat up oil before the bus even started, possibly running on WVO 100% of the time.
Even further, I could insulate the WVO bay and add it to the house heater's zone of influence so that I wouldn't have to keep heating up cold oil.
Centrifugal filter? <- seems very promising
Onboard flash dewatering? This is a bit of a holy grail for WVO, but I think it's easier on a bus with elec. power - see biodiesel.infopop.cc forums
Maybe just buy filtered/dewatered WVO and only have a clean tank with heater?
Non-pushlock? The bigger pushlocks are *very* hard to get hose on.
More quick release connects?
More swivel fittings for ease of assembly/disassembly!!
It would be interest to make a floating pickup for the dirty tank, so that I'm always skimming from near the top. And it would be nice to figure out how to clean out stuff that has settled on the tank bottom, maybe a squegee with a flexible shaft that I can get through the tank opening.
NOTE (Thanks Royce Owen - roycegriffon yahoo): Some engines are equipped with a DDEC system which has sensors for low pressure, low coolant, too hot coolant, etc.. and will shut down the engine. The DDEC computer is cooled by incoming fuel, which can be a problem if you heat it to 180° F. DDEC is the box with a mess of wires on it sitting on top of the engine right behind the long fan belt. If you have one, you probably also have a large square red button on the left side of the dash that says "engine over ride" (which allows buses to drive another 30 seconds after DDEC is triggered).

Troubleshooting

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

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.
Power loss	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
Not Enough Heat	"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