Project: Helga

Meet Helga, my new veggie Mercedes!  Helga is a 1970 Mercedes 220D diesel built by hand in Stuttgart, Germany.  She has a 2.2L IDI engine with cast iron head.  She's peppy with her little 4 speed manual gearbox!  

Helga paid a visit to Vegenergy Fuel Systems in Atlanta this past spring and went under the knife of master welder and veg converter, Dezso from Hungary.  The system was custom-designed to meet the veg-burning requirements of an antique Mercedes.

I spent this summer testing the conversion and making adjustments to the system to optimize it for a daily commute of 80 miles roundtrip.  After several tweaks, she makes the trip flawlessly at least two times a week.

Here is a peek under the hood!

Modified Engine Bay: Frontal View

Modified Engine Bay: Drivers Side View

Modified Engine Bay: Passenger Side View

The veggie steel tank was custom built by Dezso.  It is an inverted Veg-Wedge design to account for the angled seat back in the 220D.  It holds the same (@17 gallon) capacity as the Veg-Wedge.  There is an internal coolant-based heat exchanger with all welds on the exterior of the tank to prevent leaks.  External plumbing is hard lines through the trunk floor where it meets soft HOH plumbing.  The fuel gauge is mounted in the trunk to allow for monitoring fuel level while filling.  The fuel cap is vented to allow air to enter the tank to displace spent fuel.

Custom Veggie Tank in trunk

Close-up of external welding and hard lines through trunk floor

The HOH lines are made by Parker for Golden Fuel Systems. (formerly Greasel)  They are mounted underneath the vehicle and enter the engine bay on the passenger side. 

Close-up of Pollak Valves

The picture above is a close-up of the two 6 port Pollak valves used in the system.  I have heard many stories of Pollak valve failure but haven't encountered this on my vehicles yet.  I may buy a spare 6 port valve to keep in the car in case of failure. (I highly recommend assembling a Veg Emergency repair kit in a small tool bag to carry with you in any veg cars.  I haven't needed one yet but I'm sure I will one day)

The first 6 port controls the switching from diesel to veg.  It takes two 3 port connections in order to achieve having the veg filter on the pressure side of the system and share the existing lift pump.  Diagrams of the VegMyRide/Vegenergy conversions are available on the VegMyRide DVD.

Close-up view of the VegPower Heated Filter

Helga has a coolant-heated veggie filter from VegPower Systems in Ithaca, New York.  It uses standard fuel filters available from NAPA, Baldwin, Wix, Donaldson, etc.  There are extra capacity version filters available (longer body) for truck systems or car systems with more clearance below the filter head.  The VegPower filter does a very good job of heating and filtering the vegoil before it enters the final fuel heat exchanger and eventually, the injectors and pre-combustion chamber.

Close-up of Arctic Fox Final Fuel Heat Exchanger

Just below the upper radiator hose in the picture above is the Arctic Fox final fuel heat exchanger.  It is used to heat the veg oil externally one last time before entering the injectors and pre-combustion chamber.  The goal is to get the veg oil to approximately 150-160*F before entering the injectors.  While IDI engines such as the Mercedes 115/123/126 models can probably handle colder temps, this is the accepted benchmark to reach independent of diesel engine make and model.  (direct injection engines and high pressure injection systems are far less tolerant of thicker veg oil.)

Close-up of fuel switching toggles under dash

The switches for controlling the fuel system are located under the dash on a switch panel.  The left switch toggles between diesel and veg fuel systems.  "Left is diesel; right is veg oil"  The switch on the right toggles between diesel return and looped return.  "Left is return; right is looped" 

In the picture above, the switches are both in the left position indicating that it is in normal diesel operating mode.  Once the engine reaches temperature, both switches are toggled to the right simultaneously.  This switches the fuel supply to veg oil and loops the return.  When time to purge, the left switch is turned back to veg oil (left) and is driven for about a minute before switching from looped to diesel return.  This allows for the veg oil in the loop to be diluted with diesel before switching back and returning the contents of the loop to the diesel tank.  There is a little veg oil that enters the diesel tank but not enough to make a difference.

If you have additional questions about this system, please feel free to email me at powell@southerngrease.com.  You can also get detailed information on this conversion system by watching the VegMyRide DVD. (fuel diagrams are also available on the DVD)