Lessons learned from my conversion of a 1984 Mercedes into a grease-mobile
Posted 09.28.2009 at 2:09 pm
10 Comments
Purchasing a 1984 diesel Mercedes Benz 300TD
Mikey Sklar
Without any sort of approval from my girlfriend, I bought a 1984 diesel Mercedes-Benz through eBay. Two years later, the vehicle has provided me with nearly 10,000 miles of service on waste vegetable oil (WVO). The fuel may technically be free, but it has not come without a price. Here's how I converted my car, affectionately known as "Chance," to a veggie-oil roadster, and some of the hard-learned lessons I picked up along the way.
I started with a WVO kit from Frybrid. This company sells a rather high-end (~$2,000) setup for my model of Mercedes. The primary components are:
- Heated fuel hoses (hose-in-hose)
- 20-gallon fuel tank (with heat-exchange)
- Heat-exchanger under the hood
- Heated fuel filter
- Embedded computer to control dummy lights and switches between stock diesel tank and veggie oil tank based on radiator temperature
Secondary veggie fuel tank in trunk: Mikey Sklar
The idea is simple enough: Place a second fuel tank in the trunk and wait for the vegetable oil to reach a combustible temperature of 160°F. The temperature is important because vegetable oil is much thicker than diesel at room temperature, so you have to get the viscosity thin enough so the pumps and injectors can move it. By tapping into the car's radiator hoses, the engine heat can be transferred through heat exchanges to warm the vegetable oil. Frybrid provides a reasonable kit, but to be honest, I wouldn't do business with them again, as their customer service wasn't the best. My system came with a faulty temperature sensor that I was unable to get replaced.
Under the hood - A mess of fuel hoses and solenoid valves: Mikey Sklar
My conversion took one week with the assistance of a professional diesel mechanic. It was a stressful process ripping apart the car and just hoping that everything would work in the end. Having a mechanic around to offer tips, tricks and tools, and to make minor repairs on the ancient vehicle, helped quite a bit. I don't recommend taking on your own conversion if you're not already well versed with the automotive world. The downside of having a mechanic around is the cost (~$1,500).
Here are a few other bits of advice for anyone else considering such a project.
Do not buy an old car.
I'm not kidding -- this was the single biggest mistake I made. Burning veggie oil is just a matter of heating and filtering, but keeping a 25-year-old car on the road is an entirely different challenge. If I were to do it again I would buy something made in the last 10 years that was well taken care of. I have spent just as much on repairs totally unrelated to the veggie oil as I did on the entire vehicle + conversion + installation. At this point the door locks do not work, the A/C and heating in the cabin are unreliable, the stereo is dead, and the odometer has been stuck at 86,000 miles probably sinces the early 1990s.
My girlfriend pumping waste oil behind a gas station in Marfa, Texas: Mikey Sklar
Oil collection and filtering is a skill.
I have an overpriced gear pump setup called the one shot. I like it because it's self-contained in a Pelican suitcase, and includes a high-quality filtration system. But getting clean oil that won't clog the vehicle's fuel filter every 300 miles takes more than just this hardware. I like to collect oil from a local restaurant and let it sit for 30 days. Then I run the oil through a highly technical denim filter (literally old jeans from the thrift store). Finally, I use my one-shot to filter the remaining particles down to two microns out of the oil.
Consider making biodiesel
Lots of folks mix up the difference between WVO and biodiesel. Biodiesel is made through a chemical process usually combining lye and methanol with waste vegetable oil that causes the glycerin to drop to the bottom and leaves the lighter biodiesel to be poured off the top. I purchase methanol from a local car-racing supply store and lye from a pet-food shop to make biodiesel at home. It costs me roughly a $1 per gallon and prevents me from having to purchase diesel fuel for the cars stock tank. Just be careful: Both methanol and lye are hazardous.
Refilling the veggie tank during a road trip: Mikey Sklar
Making your own fuel and converting a car is an adventure, and that's really the primary reason to do it. Once you take into account the materials you need to buy and the time involved with maintenance and fuel production, I'm not sure that a real savings can be found. In my next post about Chance, I'll include some performance data looking at one year of driving on WVO.
Want to read more articles like this, plus tips and tricks, home hacks, DIY projects, and more? Subscribe to Popular Science today, for less than $1 per issue!
10 Comments
To comment, please Login.
Popular Tags
Regular Features
140 years of Popular Science at your fingertips.
Popular Science+ For iPad
Each issue has been completely reimagined for your iPad. See our amazing new vision for magazines that goes far beyond the printed page
Download Our App
Stay up to date on the latest news of the future of science and technology from your iPhone or Android phone with full articles, images and offline viewing
Follow Us On Twitter
Featuring every article from the magazine and website, plus links from around the Web. Also see our PopSci DIY feed
April 2013: How It Works
For our annual How It Works issue, we break down everything from the massive Falcon Heavy rocket to a tiny DNA sequencer that connects to a USB port. We also take a look at an ambitious plan for faster-than-light travel and dive into the billion-dollar science of dog food.
Plus the latest Legos, Cadillac's plug-in hybrid, a tractor built for the apocalypse, and more.
Popular on Popsci
Most Commented
Most Emailed
Most Viewed
Online Content Director: Suzanne LaBarre | Email
Senior Editor: Paul Adams | Email
Associate Editor: Dan Nosowitz | Email
Assistant Editor: Colin Lecher | Email
Assistant Editor:Rose Pastore | Email
Contributing Writers:
Rebecca Boyle | Email
Kelsey D. Atherton | Email
Francie Diep | Email
Shaunacy Ferro | Email
Today on PopSci.com
Copyright © 2012 Popular Science
A Bonnier Corporation Company. All rights reserved. Reproduction in whole or in part without permission is prohibited.
daniel brown back in the 70's Iowa university said that cutting the oil with %10 methanol would cut the glycerin into small pieces that the would not gum up the the pumps and injectors. and thin it down.
This is one seriously awesome use of an old merc, but would using a newer car really work - I might try it with my 02 c class? What do you think - sensible?
www.ibenz.co.uk
Too new a car is going to have way too many computers and may be mechanically damaged by running biodiesel. The old Mercedes or VW is the better choice because Mercedes, back then, condoned the use of a bunch of oils if diesel wasn't available. The engine/diesel pump tolerances probably weren't as close as they are now either. That's why veg oil/bio diesel people are using a lot of the old Mercedes and VW's. Mercedes can apparently supply almost any repair part for any vehicle it has ever made in the last say 100 years according to its advertisements, so it might cost you a lot but there is parts availability.
Is there a lesson to be learnt here? Only environment conscious users who love the earth would try such an experiment. Hope others are inspired enough to attempt.
Raj
www.impigertech.com
If this is what one person with a little bit of ingenuity and a sense of adventure can do, what could a seriously committed industrialized society accomplish if it made up its collective mind to eliminate fossil fuels and dependence on foreign suppliers. Lets go corporate geniuses!
Terry
www.massageschoolsguide.com
Thank you for this writeup. I was considering converting my BMW to run on vegetable oil, but was hesitant to go ahead with the project. Your article gave me some valuable insight regarding this, so once again, thanks for taking the time to detail the whole process. www.kitchenchalkboard.net/
Excellent write up! I operate a local shuttle called The-Climb (.com) which runs on our co-op made Biodiesel and WVO. Running a 2003 E450 on WVO at 5200' to 8300' in cold winters is interesting but not difficult, and has resulted mostly in loose hoses and gaskets and rust in the gas tank ( go stainless).
The best part of your write up was the use of an old vehicle. I also use a 2005 Sprinter on biodiesel and WVO, and the computers do have troubles at times. The E450 has had no problems as far as fuel is concerned. Another note is that I did my first conversion myself and my second with a mechanic. My second still runs well.
Great article Mikey! I work at this place called The Positive Thinking Playground ( www.monalle.com ) and my boss is supposed to do this nationwide tour next year... He wants to do it in a late model 5 cylinder turbo diesel Sprinter running Bio-diesel...
I keep telling him to get an old Mercedes Diesel wagon and do it on WVO so that he can just fuel up at fast food places and do the whole tour super cheap (bio-diesel on a nationwide tour seems hard to get a hold of)...
Now after reading your article and ShipyardPhil's comments I see that he's right, the late model vehicle that can run Biodiesel, Diesel, and WVO is definitely the best option!
He may not admit it, but since I've been his assistant for two years now, I'm actually the one that makes all the decisions... And after reading about your headaches with the older benz, I've defintely decided to go with the newer Sprinter and three way (hippy flex-fuel) option...
So thanks for the great advice! Long live plant based fuel sources!
Yours to a renewable sustainable future,
Elly
That's cool. You wouldnt expect to see a Mercedes Benz running on an alternative fuel. A small, inexpensive car would be a more likely conversion, but it's good to see the larger vehicles can make use of it.
Beecher Bowers
www.beecherbowers.com
I used a mixture of 60/40 veggie oil/diesel for about 3 years in my Ford Mondeo without any sort of conversion, directly in the fuel tank. But i have to admit that in colder weather there will be problems if the fuelmixture is not preheated. I used the 60/40 in 20 celcius(and up) driving from Amsterdam to Paris and back on a bi-weekly basis with no problem whatsoever. With 15 Celcius I had to scale back my mixture to 30/70 . Because of the fact that lots of people start following my example the goverment in Holland raised the cost of veggie oil equal to the price of diesel. I sold the car 2 years ago, and it is still on the road.