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Omnitek develops diesel-to-natural gas engine conversion kits for Mercedes OM904/OM906

Diesel to natural gas conversion system. Click to enlarge.

Omnitek has developed a kit that can be used to convert the globally popular Mercedes diesel engines OM904 and OM906 into natural gas engines.

Omnitek’s proprietary diesel-to-natural gas engine conversion kit is used for bus and truck applications, as well as stationary applications. It simplifies the engine conversion process by integrating the ignition control and electronic fuel injection into one control unit. The system offers closed-loop fuel control for low emissions, as well as J1939 CANbus communications with electronic gauges in the dashboard.

The Omnitek Kit includes all components needed to convert the diesel engine into a natural gas engine, such as low compression pistons, natural gas fuel injectors and ignition components, as well as an advanced electronic control module and multiple sensors. For applications requiring extra-low emissions, such as EURO IV or EURO V, Omnitek can also supply catalytic converters.

The conversion steps entail:

  1. Disassembling original engine.
  2. Checking components and replacing as necessary.
  3. Modifying pistons for gas use (lower compression ratio).
  4. Modifying cylinder head for spark plugs.
  5. Installing camshaft sensor and timing wheel.
  6. Reassembling engine.
  7. Installing throttle body, ignition system, gas mixer or fuel injectors.
  8. Tuning of the engine (fuel and ignition).
Finished engine
Conversion in progress. Click to enlarge.   Finished conversion. Click to enlarge.

For engines without turbocharger, the conversion cost is $7,000 - $10,000, including Omnitek Kit, Engine Modifications, and Labor. Gas tanks, engine overhaul parts and installation are extra. For engines with turbochargers, the conversion cost runs to $8,000 - $12,000. A Team of 5 - 7 technicians can convert 5 - 7 vehicles in one week.

Truck and bus operators have been particularly hard hit by the increase in the price of diesel, to a point, where converting to natural gas is many times the only way to stay in business. Converting to natural gas will not only reduce fuel costs, but also air pollution. It was particularly important to us to develop a system that is affordable and offers a rate of return around one year, and I think we have succeeded.

—Omnitek CEO Werner Funk

Piston modified for ng
Piston modified for natural gas. Source: Omnitek. Click to enlarge.

A converted bus with an OM904 engine has been operating in Mexico since January 2012. The lower priced natural gas is saving the bus operator 40% in fuel costs. The reduction in particulate emissions by more than 90% and lower greenhouse gas emissions (CO2) by 30% are further benefits offered by diesel-to-natural gas engine conversions.

The project in Mexico is managed by NatGas S de RL de CV, the Omnitek representative in the territory.

Earlier this month, Omnitek entered into a definitive agreement with investors for a private placement of common stock and warrants to raise approximately $5.0 million in gross proceeds. The funding is targeted to accelerate the build-out of a national network of diesel-to-natural-gas conversion facilities.



All it would take is one fleet operator converting a bunch of vehicles, installing a fueling system and offering fuel to the public as a side business and the ball would be rolling in any particular area.  Once the investment is reduced to increments of one engine, it'll be a lot more attractive.


Probably natural gas is a better option then batteries.
Im interrested to buy a bi-fuel nat gas and gasoline car with 2 tanks one for gasoline 87 octane and one nat gas tank with 105 octane nat gas. Also im interrested to buy a small miniature home nat gas maker feeded by grass , wood, sewage, papers, atmospheric co2, etc.


This could be very interesting and profitable for countries like USA/Canada with many heavy diesel trucks and over supply of low cost NG. In most cases, the $12K conversion cost could be recovered in less than one year.

By the way, it is much cheaper than the $50K that crude oil supporters claimed. All diesel-electric locomotives could also be converted. to make it happen over the (R) and Oil people objectors?

Nick Lyons

Great program--recycles existing equipment, provides jobs, lowers emissions, reduces oil imports, saves money. Talk about your economic stimulus...

It would be interesting to hear more about the operating characteristics of the converted engines compared to the diesel originals (torque, power curves, etc.) Do automatic transmissions have to be re-calibrated to work with the converted engines? Etc. etc.


$12,000 plus labor and cost of money puts it at perhaps $15,000 cost of conversion. This is a UPS truck, NOT an 18 wheeler...don't get carried away.


BOTE here:

If an E350 gets 9 MPG, a larger step van probably gets 6 MPG.

Such a vehicle driven 80 miles per day 250 days per year covers 20,000 miles/yr; at 6 MPG, it burns 3,333 gal/yr.

If the fuel is changed from $4/gal diesel to $1/gde CNG, the savings are $3/gde or $10,000/yr.  The payoff is less than 2 years for this case, and approximately 3 years for the 40 mile/day case.

This looks like a very attractive business proposition.  The only wildcard is the cost of the fuel and/or central fueling system.


It will be a big help, but in response to the "crude oil supporters" comment, it is not a big rig being converted to LNG. That could cost $50,000 per unit.

My point was do we as a nation want to convert 1 million big rigs for a total cost of $50 billion or do we want to build 50 natural gas to diesel plants that each produce 1 million gallons per day?

Some people may not think about the country but I do. Some may say that as long as individuals and companies head in the right direction, everything will be OK. Well that is not always the case and I think most of us know this by now.


You are going to object to this because you can't do the math to follow it, but I'm writing for the broader audience.

My point was do we as a nation want to convert 1 million big rigs for a total cost of $50 billion or do we want to build 50 natural gas to diesel plants that each produce 1 million gallons per day?
We want to convert the big rigs.  Here's why:
  • Both CNG and LNG burn cleaner than diesel.
  • CNG and LNG avoid the losses of GTL (about 55% losses in the Indonesian GTL plant covered by Robert Rapier).
  • The USA burns about 3.8 million bbl/d of distillate, roughly 22 trillion BTU/d or 8.1 quads/yr.  The USA also consumes about 24 trillion ft³ of natural gas, or about 25 quads' worth.  It's much easier to increase gas production by about 32% for CNG/LNG than to boost it by 72% for GTL.
  • Market conditions can change very rapidly, and it makes far more sense to invest in a rig conversion with a 15-year lifespan than major chemical installations with 50-year lifespans.
Really, there's no question about it.
Some people may not think about the country but I do.
You only think you're thinking about the country; you're actually not thinking at all, just re-arranging your prejudices.



You must know that I don't read anything you post, because you are insulting and rude, so just save the time and go back to The Oil Drum.


Since I said flat out I'm not writing for you, you needn't bother responding.  And the reason for CNG/LNG that I forgot in the previous list:

  • CNG/LNG remain viable options even if LNG exports bring North America gas prices up to the ~$14/mmBTU they'd merit on the world market.  At those prices, GTL diesel at 45% conversion efficiency would have a feedstock cost of $4.35/gallon before amortization plus O&M.
If you really think about the country, considerations like this should be foremost in your mind.


I will not be commenting further on GCC until EP leaves. It has been fun reading and commenting, but I will not put up with the rudeness.


E-P may be rude (sometimes) but he seems to have an open free mind without an agenda. Using locally produced CNG directly for trucks and locomotives would produce less emissions and reduce crude imports.

Converting existing heavy vehicles with 50+% of their expected useful life duration remaining could be an excellent make work project to help USA out of the current recession.

It is difficult to be against and claim to be a real green nationalist at the same time.

Roger Pham

Thanks, E-P, for the info.
It's encouraging to have actual price of diesel to NG conversion instead of just guessing, and the price for converting a DB turbocharged 6-cylinder engine is only $12,000 including labor. A heavy-duty engine may be twice as large, but will not cost twice as much to convert, since labor cost won't be increased by much, and part cost won't double, either, since labor cost accounts for a pretty large proportion of part cost, and steel and aluminum are relatively cheap. Electronic controller will cost the same. I would estimate a "big-rig" diesel engine conversion to cost under $18,000. Perhaps eventually a lot less than that with eventually mass production of parts in tens of thousands to hundres of thousands of units.

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