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Retired Master Sgt. David Flint, who now works with Marine Corps Base Motor Transportation, adjusts the system that allows his vehicle to run on vegetable oil.

Photo by Lance Cpl. Drew Barker

Retired Motor-T Marine converts car to run on vegetable oil

12 Jun 2006 | Lance Cpl. Drew Barker

Adapt and overcome. Marines hear this expression on a daily basis and understand exactly what it means. It encompasses the very fundamentals that make up the foundation of the Marine Corps attitude. When Marines are presented with a task, face adversity or negotiate everyday obstacles, this is their mantra.

The phrase means to adjust one’s attitude and approach to a problematic situation accordingly in order to accomplish the given mission. And that’s exactly what David Flint, a retired Master Sergeant, did last February in response to the seemingly endless increase in gas prices.

“By that time, it had been out of control for a while,” said Flint, who is now the quality assurance evaluator with Marine Corps Base Motor Transportation. “I knew I had to do something, not just to save money, but to try and make a difference. So I started investigating.”

Flint discovered a small company based in Seattle who sells specialized kits used to convert a diesel engine to run on standard vegetable oil.
“I found them on the internet,” said Flint, a 48-year-old native of Hubert, NC. “The thing is, the conversion kit only works on diesels, so I needed to find the right vehicle.”

After much deliberation and research analysis, Flint decided on purchasing a 1985 Mercedes Benz 300D, a mid-size luxury sedan, for his experiment.

“The diesel engine in that thing is so well built,” said Flint. “I knew it would handle alteration well and bought it expressly for the project.”

According to Flint, the first diesel engines were originally designed to run on peanut oil, so this concept really isn’t that far fetched.

“It makes great sense,” said Flint. “It’s a renewable resource, it’s much better for the environment and, in case you haven’t looked at gas prices lately, it’s economically sound.”

Flint received the kit and spent only two days installing it in his new, used car. The process was relatively easy for Flint, who has a working knowledge of the diesel engine and automotive mechanical experience from nearly 30 years in the motor transportation maintenance field.

“Even if only one person does this, it can help ease the burden on our country’s oil situation,” said Flint. “But it may not be for everyone. You have to understand how an engine works to some degree.”

Flint explained the engine must begin running normally on diesel fuel until the vegetable oil reaches the proper temperature and viscosity, one closer to that of diesel. A sensor alerts the driver when the engine is ready to make the changeover, and with a flip of a switch, the engine makes a seamless transition. The final stage in the cycle is to purge the vegetable oil from the engine and return to using diesel fuel just before reaching the final destination.

Although vegetable oil and diesel fuel are comparable in cost and average close to the same miles per gallon, Flint has found a way to save money and make both environmental and economic impacts.

“I use waste vegetable oil I get from various restaurants around town,” said Flint. “I have to filter and remove any water from it, but I get it for free, so it’s well worth it.”

More often than not, restaurants have to pay a fee to have the used vegetable oil taken away and disposed of, because it is classified as a waste product.

“They don’t have any use for it anymore,” said Flint. “A lot of times I’m doing them a favor by taking it away for free, and everything I do with it is completely safe for the environment.”

In the four months since installing the system, Flint and his partner, Christine Henderson, have driven over 4,800 miles on vegetable oil and used less than five tanks of diesel fuel in the process.

“I love driving it,” said Henderson, who uses the vehicle almost everyday to commute at least 60 miles to and from work. “It’s very, very fuel efficient. We get close to 1,800 miles on every tank of diesel. It’s very easy to drive, and I rarely have to stop for gas.”

The kit, which cost Flint and Henderson nearly $2,000 to purchase and install, will have paid for itself within the next few months through all of the money saved on gas, according to Flint.

“This is just my way of contributing less to the negative,” said Flint. “There’s no reason we should help oil companies make record profits.”

Although the conversion system may seem flawless, it does have a few drawbacks in relationship to its uniqueness.

“I haven’t heard of anyone else in the area doing this,” said Flint. “If I were to take this vehicle to a mechanic out in town, they wouldn’t even know what they were looking at. So if something goes wrong, I’ll have to fix it myself.”

Another distinctive feature of the engine running on vegetable oil is the surprisingly familiar and delicious scent of the exhaust.

“You’ll be driving along and realize, ‘Man, that smells good,’” said Henderson. “It’s like someone’s sitting in the back seat grilling up some burgers and fries.”

Despite the extra effort required to operate the modified vehicle, Flint has nothing but good things to say about the experience.

“I love it,” said Flint. “I haven’t had a minute’s problem with it and I can’t wait to do it again.”

Flint is currently awaiting delivery of his second kit, which he plans to install in his Dodge pick-up truck.

“I can’t wait to get this system in my truck,” said Flint. “It makes us less dependent on foreign oil, it’s a renewable resource, it has fewer emissions than fossil fuels and it’s grown right here in the U.S. From these standpoints, you just can’t beat it.”