97 Merc 250TD W202 Suggestions on best WVO Setup

[Harvey Member Find all posts View Profile Close Harvey]

Dear Brains Trust
Recently aquired the above vehicle and it's beautiful to drive and loves B100.
I would also like to simplify fuelling including minimising playing with hazardous chemicals, so thinking about wvo.
On this car will a one tank system suffice? What will that require? FPHE, Elec heaters? Special injectors?
Will appreciate and consider all thoughts..
Thank you in advance
Kind regards Harvey

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: 97 Merc 250TD W202 Suggestions on best WVO Setup

Harvey,
I ran mine on WVO for 2 years but had issues with the venturi pumps. I changed to Biodiesel and still have he same issues, so not the fuel.
Have a read of my posts on the saddle tank and return line issues (in the W202 section).

If your car runs reliably and you can drive until the low fuel light comes on, then I cannot see any issue with running it on veggie oil.
In winter, I would add up to 15% ULP as a thinning agent.
Ensure that your fuel line O rings are in good condition, as the lift pump will put additional suction on them due to the higher viscosity of the oil.
The engine includes a heat exchanger in the fuel system, prior to the prefilter.

You may wish to add an electric fuel pump to assist in priming the fuel system if you run out of fuel.

Regards,
Tony

[Harvey Member Find all posts View Profile Close Harvey]

Re: 97 Merc 250TD W202 Suggestions on best WVO Setup

1. Yes intending on a facet pump (4psi?) near tank to push wvo
2. Will follow Tony's posted solution on this and Merc forums should the saddle tank issue occur
3. Blending makes good sense. 15% winter sounds good advice. Any advice regards % for warm weather?
4. I can't find specs on The heat exchanger in this engine. It's great having a German engineered one as standard hardware, but I would love to understand it better. How does it work? Is it heat from the water jacket? There seems to be wires from/ to it? Have spent days asking professor Google but can't find anything!
5. What am I missing?

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: 97 Merc 250TD W202 Suggestions on best WVO Setup

Harvey,
Responses to your questions below.

1. Yes intending on a facet pump (4psi?) near tank to push wvo

Careful, the facet may not allow the high fuel flow this fuel system uses. If you were to put a Non-Return Valve in parallel with the facet (2 Tees, with the facet on one arm of both, the NRV on the other arm of both and the fuel in and out to the leg of each Tee), the high flow would go via the NRV, but the Facet would be there to prime the fuel system.

2. Will follow Tony's posted solution on this and Merc forums should the saddle tank issue occur
3. Blending makes good sense. 15% winter sounds good advice. Any advice regards % for warm weather?

I had no problems with 100% veggie in summer, 10% ULP caused vapour lock (hard starting when hot)

4. I can't find specs on The heat exchanger in this engine. It's great having a German engineered one as standard hardware, but I would love to understand it better. How does it work? Is it heat from the water jacket? There seems to be wires from/ to it? Have spent days asking professor Google but can't find anything!

The heat exchanger is on the head and coolant provides the heat. There are no wires to it on either of our C250Ds

5. What am I missing?

[Harvey Member Find all posts View Profile Close Harvey]

Re: 97 Merc 250TD W202 Suggestions on best WVO Setup

Thanks Tony, I greatly appreciate the advice. Good thought on how to plumb the pump so that it 'may' assist but can't inhibit flow.
Cheers Harvey
p.s. Loving driving the c250td