DIY WVO conversion feedback...
 

Hey all, first off - I joined mercedesshop.com only a matter of days ago and I can't get away from it. I've had my 79 300D for just under a month, and having limited knowledge about diesel engines and having never owned an MB, this forum has been fantastic. So thanks to everyone.

I really dig this car. She's got a few blems and mis-matched hub caps, and it seems the starter died today, but what a solid and comfortable ride.

Anyhow, like many these days, I bought "Helga" with the intention of converting to WVO. After just a little research, the concept seemed pretty basic and I feel confident that I can do the conversion myself and save upwards of $1000, and so I'd like to know if anyone here has done a conversion from scratch. I've been surfing for days/weeks (including many of the links under the WVO links thread) looking for a good comprehensive outline on the subject and so far all have I found in any detail is here (despite the inaccurate juxtaposition of grease and "gas":rolleyes:). Click the "Convert Now" button. I just copied and pasted it into notepad for easier reading.

Hoping for some feedback about this short write-up from any who have done their own WVO conversion.

thanks again

Ruben

To safely WVO there are some simple (though not necessarily easy to accomplish) things that are required.
1) WVO needs to be well filtered
2) WVO needs to have all the water removed
3) WVO needs to be heated to around 160* F (minimum) before it gets to the pump & injectors. 180*F-200*F is even better

Some people swear by the idea of heating the whole tankful of oil. Others say it speeds oxidation and polymerization of the oil (creating a varnish-like substance in the tank)

It is generally agreed that the best way to do it is a 2-tank system. A small tank to hold diesel and a larger tank for the oil and a switching valve to change over from one tank to the other. The idea is to start and run the engine on diesel, until the oil gets warm enough, then switch over to veggie oil. When it is time to shut the engine off, switch back to diesel long enough to pump and burn the rest of the veggie oil in the fuel lines (purge the oil) so that you have fresh diesel in the system for the next startup.

The reason for heating the oil is that cold oil is too thick (high viscosity) to be pumped without putting a strain on the injection pump - not good for it. It is also too thick to be atomized well at the injectors. Poorly atomized fuel doesn't burn well and coats your cylinders and piston rings, where it then carbonizes and polymerizes making a sticky mess of your rings. Also not good. The oil can be heated using electric heating elements or engine coolant (run through a heat exchanger) or a combination of both.

If I were doing it I wouldn't heat the tank, instead I'd use an electric pump capable of handling the cold thick oil - to pump it up to the engine compartment where all the heat is. I'd install a coolant-filled heat exchanger to heat it up, and then a smaller electric heater just before the injection pump to make sure the oil goes into the pump nice & hot. I'd also put my switching valve as close to the pump as possible - to minimize the amount of oil that nees "purging" from the lines before shut down.

For making it switch over from diesel to veggie I'd use a temp switch to energize a (normally open) relay as the control for the switching valve. That way I would be able to make sure the engine and the oil were hot enough before it would automatically switch from diesel to veggie oil. A simple push button switch would be used to energize and latch another (normally closed) relay to kill the power that energized the first switch over relay and to switch the valve back to diesel. This normally open relay would be powered from a circuit that is only "hot" when the key is in the run position.

That way all you have to do is push one button to switch it back to diesel and start the purge cycle. After it is purged, once the key is turned off, there are two possiblities. If the engine is allowed to cool down below the activation temp of the temp switch before before you restart it, then it will start up on diesel. BUT, if for some reason you restart it before the temp siwtch cools down below its activation temp, then the temp switch and relay will automatically switch it back over to veggie oil. Of course if you're only shutting it off for a short time (going into a store or whatever) you wouldn't bother with the purge because the oil will stay hot enough to be OK for restarting it for a while (exactly how long would is something you would need to determine). Basically an automated switching system with a manual start for the purge cycle.

I thought about automating the purge cycle too - basically adding a control that would allow it to continue to run for a specified time after you turn off the key. I decided I didn't like the idea of locking and walking away from my car with it still running though. I'd rather get into the habit of pushing the purge button a minute or two before I arrive at my destination when I'm going to be parking it long enough to cool down. I guess I could do both. Make it continue running in an automatic purge mode if I just turn off the key, but still have the button to initiate the purge manually. I'll have to give that one some more thought.

Anyway, I've already given some thought to this (can you tell?) but have actually decided against doing it. I going to partner with a buddy of mine to brew home-made biodiesel instead. It is a little more work, but doesn't require adding a second tank or any other hardware to the car. I've pretty well decided that since my 300CD is so unmolested, I'd rather leave it unmodified.

Sorry for rambling - I hope some of it proves useful.

Biodiesel is always the better (and legal) alternative.

Keep looking into it, I think you'll find its tough to actually save much money doing it yourself, unless you're good at welding aluminum and have access to a machine shop. Well, you can throw something together cheap, but you might have some long term reliability issues. Read some of the VO forums, there's much more in-depth info there (infopop, frybrid, greasecar).

I can't get your site to work, though I am using Linux, maybe it is on my end...

Anywho, I studied the infopop board, this board, Frybrid, and Neoteric, and came up with my own system which worked great. I did buy the Vegtherm, a Racor 500FG, and of course went two-tank with the looped return.

I worked with the biofuels coop in Santa Cruz dispensing info and holding workshops. In the end, though, many of us came to the conclusion that veg oil was not all that sustainable, because of what comes out of the tailpipe; as well as what veg oil all too often does to a Mercedes.

The solid particulates that are emitted from using veg oil need to be looked at in any discussion about veg as fuel. They are way up there, bad news, unfortunately.

And though I know I did my system as well as can be done; with a temp gauge on dash telling me exactly how hot that oil was b4 i flipped the switch to send it to the IP; still there are concerns, every tankful, of minute water particles attacking the IP and injectors.
Also, what long term veg does to rubber in the IP. MBZ mechanics will tell you all day long about the damage done to these cars via veg conversions. You might notice a little hostility in this forum regarding veg; these folks love their cars, and know what veg can do to them.

You have to ask yourself; is this an old beater who only has a few thousand miles in her anyway? or am I willing/financially-able to swap out the IP and injectors down the road to save her?

In the end, after endless hours of research and trial, I disconnected my fuel lines and went back to bio-diesel.

I am very concerned about sustainability, truth be told. While BD is expensive and 20% petroleum derived, it burns much cleaner than veg oil. It is much safer for my car, meaning the car lives longer (consider the environmental hazard posed by sending cars to the dump prematurely !).

If you use veg, you must dewater it. That consumes a lot of energy right there. You must filter it excessively. It is also of concern that there are legal issues to contend with. And then you spew out a great deal of solid particulates for all to breathe; it is the sad but true story of veg oil.

These are all parts of a rather complicated decision the environmentally mindful of us must make.

Also of concern, a veg oil conversion will require continual care, and will periodically leave you on the side of the road, no matter how good the system, is what I have seen. Therefore, high-maintainance imho; and not for the non-mechanic.

Looks like you might be in the Bay area; I am often there and can offer you to take a look at my system; it is all still there. Fwit, I think it is the best, most longevity minded way to do a two-tank.

Peace!

Hey, when you do that starter, get a new battery (dying starters eat batteries for lunch) and ensure your alternator is up to par. You will thank yourself down the road :cool:

Jimmy Joe, I am use Linux and I can get to the site....

I had that intent when I bought my first MB, too. But now I can see that all the work involved in modifying the car and filtering, dewatering, and hoping for WVO that isn't contaminated or pH'ed wrong is really hard and may permanently damage my incredible cars.

Also, I think Jimmy Joe has a good point about the energy you have to expend to make fuel. reduces the net gain, IMHO

Unlike FI, I am not too concerned about the legality, I passed my inspection with my EGR (acidentally) unplugged, and I paid my sales tax and I pay my yearly road tax (based on the vehicle weight, to account for road damage), but that said, I would prefer to buy bioD from a retailer or co-op.

I live in San Antonio where there isn't a single consistent bioD retailer, so I have considered making my own bioD. Still, it's alot of work. I would rather just buy it from a reputable retailer.

Good luck, keep us posted

I'm with you on most of what you said. I don't come down quite so much on the ecology side of the question, but the sustainability is a hot button for me, as is reducing our dependance on foreign energy, and improving the longevity of the vehicle. Saving money is up there too, so my buddy and I plan on brewing our own.

I have a comment ot two about the 20% petroleum derived comment though. Obviously you are referring to the methanol - also known as wood alcohol. Although a lot of methanol is produced from natural gas, I don't have a problem with that because 1) we have an abundant supply of domestic natural gas, and 2) the methanol can still be produced the old-fashioned way through the fermentation of wood byproducts (bark, sawdust, etc.)

Back to the question at hand...Thats a pretty good guideline. I read through many websites that have peoples write ups on what to do, and countless hours on greasecar/biodiesel.infopop forums. Read up well, all the info is out there.
My conversion took 2 weekends but the research was about 4 months. Conversion went well and continues to do well to this day

Here is my old home-made two tank system: http://www.peachparts.com/shopforum/alternative-fuels/148416-my-2-tank-svo-conversion.html

Great feedback from everyone...thanks.
I say the following based solely on what I have found through my research.
In regard to overall effects to the vehicle:
I understand oil rots out rubber seals/gaskets. I've heard as well that the high solvent properties of biodiesel do basically the same.
Damaging my vehicle is not on my "to-do" list, but both alternatives seem to be damaging in various ways, but have benefits that might arguably off-set those damaging characteristics.

Lubricity in both alternatives is higher, allegedly providing smoother operation for and extending life of metal mechanical components, yet eat up rubber fuel lines, o-rings, seals, etc.

In regard to over all cost of operating on alternative fuels:
Biodiesel is more expensive than conventional #2, at least where I am.
And if does chowder rubber parts as does VO, then it appears that bio d is a step behind in terms of practicality. Not to mention home brewing requiring high start-up costs.

ethics:
I've wondered about the high particulates put out by VO, but thought those particulates where much healthier than the soot that often dumps out of the pipes from #2. No?

Contradictorily, I'm now starting to lean towards bio d.

I'm a full time undergrad and can foresee myself being in school for the next 4+ years, I have time to work way less than 20 hours a month, and fuel costs are eating up my budget. Starting to feel pessimistic about the whole alternative fuels gamut.

Am I going to have to devote most of my time to vehicle maintenance and fuel production one way or the other? I knew it would be some work, which is fine, but if it's going to cost a load of cash, it just isn't feasible for me.


:confused::confused::confused:

My first conversion was from scratch using a plastic boat tank as the secondary heated fuel tank. It works and has worked for 2 years. 2 weeks ago I completed my second conversion ever with a greasecar system. From my experience I would go with the greasecar kit instead of building something from the ground up. While I was designing my homemade kit I had to make about 100 trips to the hardware store before I finally got everything I need. And on top of all that my tank leaks a little bit, which is messy. Get the greasecar kit for $1000 (which I believe is reasonable) and save yourself the headache and time of designing something from the ground up. Good luck...

I know that pessimistic feeling.
The reason I own a Benz is because of oil-burning capability. I spent a tremendous amount of time learning how to modify my car in the most mindful fashion. I worked tirelessly to install and perfect my two-tank. In the end, the convenience and less concerns of BD won.

I do not encourage friends to go the way of veg, unless they really really like to wrench and tinker. Keeping the car running, gathering and processing the used oil, all takes substantial time and effort and energy. (Mercedes by themselves need lots of lovin, though it is truly a car to love :cool:)
A BD car takes initial line/filter changes, but then is pretty much hassle-free. Two different worlds in commitment of hours, and in effect on vehicle.

We live in a world of compromise and convenience. I am happy to own a car that burns one of the better fuels in this day and age. And what a classy way to motor along! No fuel way is w/o its demerits; but at least folks like us are trying to make a difference in the way we consume.

Down there in the Cruz, where I rarely am all to unfortunately, BD cost the same as Diesel for the ASTM cert stuff, and cheaper yet from the homebrewers. I know there is a disparity in other places, but I pay just the same. If I had a local source of reliably clean de-watered veg oil filtered to 1 micron, I might just consider firing up the two-tank. But no way am I gonna deal with the processing of fuel again.