Fire Hydrant of Freedom

Hey Guys,

I own a Benz converted to run on vegetable oil.  There are many approaches to this concept, the key is to find the system that best works for you.

Your choices with regard to your car are two fold:
1 - run on BioDiesel (a blend of vegetable oil, methanol and lye that closer approximates the viscosity of petrodiesel).  You can make BioD in you driveway in a 55 gal drum or you can buy it at a number of gas stations that sell it.  It's no cheaper than PetroD to buy, but you can make it at your house for about 35 - 50 cents/gallon (assuming you use waste vegetable oil from a restaurant).
Pros: you don't have to convert your car, you can run BioD in your main tank.
Cons: you still have to deal with chemicals and that can be hazardous

2 - run on vegetable oil.  I did a TON of research before choosing my conversion.  There are many on the market.  They all fall into two basic categories: single tank or dual tank. 
 --Single tank conversions are much cheaper, generally $700 - $1000 installed.  But like most things, you get what you pay for.   A single tank conversion forces insufficiently heated oil through your fuel system when it is too thick to naturally flow.  Insufficiently heated oil will coat the inside of your engine with uncombusted oil and will eventually cost you a rebuild.  It also will ruin your injector pumps which is also a costly fix.  Plus if you're in a colder climate (like anywhere outside So Cal) you'll have a very difficult time making cold starts.
Pros - cheap
Cons - it will ruin your car

--Dual tank conversions leave the original petrodiesel tank and fuel system untouched, but add a second tank specifically for the vegetable oil.  The car runs on PetroD while this second tank has a heating element in it and brings the oil up to a sufficient temp so it is thin enough to be introduced to your fuel system.  Depending on the system you get, some switch over automatically, some you have to manually do it, but a two tank system is definitely better than any single tank system out there.  You will get a LOT of miles out of your diesel.  I know of a number of people who have made the mistake of getting a Lovecraft conversion done and they barely got 10,000 miles out of the car...!
Pros - you'll get a LOT of mileage out of your car
Cons - more expensive, ours was $2700 installed. (That will be paid off in fuel savings by this June, the one year mark.  I fill up on PetroD about every 5 or 6 weeks)

Regarding oil collection:
--Yes filtration is important, but your car has a fuel filtration system in it and would easily remove the particle of food suspended in the oil.  You would go through filters quicker, but you wouldn't damage your vehicle.  The real risk you run with waste vegetable oil is the suspended water in the oil.  It's essential that you let the collected oil sit for at least 6 hours at about 90 degrees to allow the suspended water to drop to the bottom of your filtration barrel, then you pump out of the top and you're good to go.  There are simple tests to check for suspended water in your oil.  I do these tests about once a month or so and have never had any water show up.  I cannot stress enough how much more important dewatering is compared to particle filtration when it comes to the life of your engine.  Water will not combust, and will ruin your engine.  Period.

Many restaurants are willing to give you their oil.  Some will reguire you register with the state so they don't get in trouble (they have to account for their used oil), but that is also a simple matter.

Hope this helps,
jvs