?s about the Veggie Oil Diesel Conversion Thing

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Sclass
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Sclass »

Gilberto de Piento wrote:
Mon Nov 16, 2020 9:45 pm
That's seriously awesome. I especially like that you fabricated your own fuel cell. I wouldn't be brave enough to trust my work for that.
You just reminded me! It leaked! :lol: I fixed it with Kreem. Then I had to fix that with an in-line filter! :lol: How fun.

HP had all the sheet metal tools in their shop for electronics enclosures. I was able to shear the six sides in five minutes on our giant shear. The tube on the outside of the copper filter heat exchanger was done on a set of slip rolls. The best part is our fab guys taught me how to use all this stuff.

Hristo Botev
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Hristo Botev »

Sclass wrote:
Mon Nov 16, 2020 9:21 pm
Goodness, that is seriously humbling. Wow.

Alphaville
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Alphaville »

Hristo Botev wrote:
Tue Nov 17, 2020 8:06 am
Goodness, that is seriously humbling. Wow.
@sclass has superpowers and doesn’t know it
Sclass wrote:
Mon Nov 16, 2020 9:21 pm

And that's it. Looks pretty easy right?
:D

no, but amazing work man

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Sclass
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Sclass »

Here are some more images. Having a little trouble finding all the old documentation on this stuff. Some is on paper so if you are really gung ho on doing this PM me and I'll send over some hardcopy of the plumbing diagrams. The looped return on an MB is counter intuitive and I always have to refer back to my notes to see how it works.

Anyhow, here is bad oil. You don't want this. You need to tell your sources you do not want this and you cannot use it. You want the dark black transparent caramel colored oil on top. Not the creamy animal fats that sink to the bottom. If you get an inch of fat on the bottom it's okay. Just decant the good stuff into your filter rig. This photo is extreme. You do not want this disposal problem. I used to compost the white part. It makes rich soil and breeds Argentine ants. Some restaurants fry with solid (at room temp) frying oil. You don't want that. Look at the empty bottles. You want pure soy, pure peanut, pure canola, pure safflower etc.. It'll save you filters and hassle of becoming a waste disposer.

The part line will move with temperature. Some say heat in the sun and clarify the oil before filtering. Others say cool the oil and decant the clear liquid. There are different strategies. I like to decant when cold because the creamy stuff will solidify in the filters and ruin them if they are not heated.

Settle your oil at least two weeks. This makes it easier on your filters. It's amazing how much ash is in the oil. Gravity is free.

Image

Here is my filter system a few years in. Every little drop spilled adds up to a sticky mess. I used cafeteria trays filched from a local college as secondary containment. Lining your floors with cardboard boxes found in the dumpsters helps too. The old oil oxidizes into a sticky resin. I never bothered cleaning up my rig much. The beauty of this rig is that it runs on compressed air. It's silent. You pump up a 5 gallon compressor tank to 100 psi and regulate down to 30 psi and push the air into the BBQ grill tank. It is completely silent once the compressor is off. Run the compressor while you fill oil and set up your collection jugs. Then shut everything down and turn on the air pressure. Go to sleep and in the morning you'll have a full can of clean fuel. This simplicity of fuel prep is going to help you survive the grind of the hobby.

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A friend of mine built this interesting recovery/filtration system. She was a starving actress and lived in her Jetta. She could filter a tank of fuel in 30 minutes with this rig. She had very toned arms. The machine is basically two water filters inline with a barrel pump from Harbor Freight. It worked well for a person without a home. She was (and still is) attractive and found it really easy to set up connections with restaurant owners to pick up oil. I couldn't find the photos but I have one of her in coveralls hunched over this contraption in an alley pumping oil. It was quite a sight. The hobby got me some very interesting connections over the years.

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I got this air tank on Craigslist free and made a vacuum recovery kit from it. You basically seal up the tank and put a hose with a ball valve on it. You pump down the tank to 28mm Hg with a cheap vacuum pump. Some people use an old fridge compressor. I had a real vacuum pump lifted from my work. Dip the hose in the dumpster and open the valve. The oil goes right into the tank. Fast. I could drain 20 gallons of top oil in thirty seconds. Silently. Try that with an electric transfer pump. This was important because dumpster diving can get you in trouble with cops, renderers and restaurant owners. Again another system where you store energy up using pneumatic power.

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In the car with an integrated filter. I got tired of lifting the tank in and out of the car because it was heavy. So I just hooked up the compressed air and filtered it in place. Note the little drip tube going into the fuel cap. Now you don't have to lift jugs/tanks in and out of the car. Less work. Remember, getting smart about it? All I had to do was remove the empty tank from the car the next day. Or, leave it in place for next week's dumpster dive.

Image

Typical plumbing to build this kind of gear. Luckily I worked in a science think tank so this stuff was everywhere for the taking. Basically you need tubes, fittings, valves and hose clamps. The only tricky valve is the Pollak three way but you can get this online or in a junkyard off an old two tank truck. Using an outboard motor boat tank from Walmart I think everything you need to convert will cost less than $60.

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Here's a pro tip. You will go through several fuel filters on your car a year. They will gradually clog enough so the fuel pump cannot keep up with the restricted flow rate. So when you replace the filter, just put it inline with your filter rig in your garage. Now you have a sub 3 micron filter. Your garage rig can generate more pressure than the car's fuel pump so you will get many more weeks of use out of the "clogged" filter. The more it clogs the better it cleans too. So the expensive car filters (I used VW Rabbit Diesel filters because they were cheapest) are used twice.

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My advice to anyone just starting out is just buy the cheapest running MB diesel you can find. Try under $2000. Don't convert it. Mix in 20% new soy oil from Costco into the fuel and drive the car. See if you like it. Then build my filter system and start collecting oil. The cheapest collection pump turned out to be a one gallon milk jug with the top cut off. You can dip ten gallons off the top of a dumpster in less than twenty seconds in pure silence. Just cut the neck off the jug and use it like a ladle.

Filter this oil. It should be easy if you dipped off the top of the barrel. Dilute your fuel and drive. Unlike new oil this will clog your filter sooner or later. It depends on how good you are at filtering. When you start out it will be sooner. Make sure you have a clean filter and tools in the trunk. Make sure your priming pump on the car works so you can purge the air while you're on the side of the road. And don't drive it bad neighborhoods where you won't want to pull over and change a filter in the street.

This is why the two tank system is so good. When you clog your oil circuit you just hit the diesel switch and go back to diesel when the car starts stammering. There isn't always a lot of warning when the car starts to stall especially if you're moving quickly down the highway. My poor wife got really accustomed to the stammer and my hand darting out to hit the diesel switch during our years of road tripping in my bio Benz. This is just part of the game. An alternative trick is putting a one gallon tank upstream of your filter that you switch over to when you get in trouble. I figured if I did all the plumbing why not have a whole tank.

Ok, hope that helps. So bottom line I suggest beginners one tank with mixed fuel in a warm climate. If you like it then you can delve further in. I pissed away over a decade doing this. Not terribly interested in starting up again.

One cool thing is you get good at chatting up cooks and cutting deals. I also met some really colorful people in the biodiesel movement back in the Bay Area. Once you learn how to convert a car you get a lot of bartering opportunities with people wanting cheap conversions.

And no this isn't technically hard. It's actually really simple. The hard part is maintaining the car, maintaining restaurant connections after management changes and moves, and keeping your oil clean.

anesde
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by anesde »

Very interesting stuff Sclass! I would be very interested in a full post of how you converted it if you would be up for it!

You say you gave up the hobby but do you still have the car? If not did you sell for a premium given the conversion?

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Sclass
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Sclass »

All my data is scattered around. I didn’t organize it after I quit. There are some good sites with conversion info. I would stick with one tanking and mixing for beginners.

I ripped all the gear out of my last conversion. It kills the value of the car. MB geeks are convinced that the conversions hurt the engines. True or not I decided to remove the plumbing and act like my car was never run on svo especially since I no longer need it.

Hristo Botev
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Hristo Botev »

@Sclass, I think you've just convinced me I really do need to just drive less. That looks like SO MUCH work!

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Sclass
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Sclass »

If you are curious this is the design used by most people. Not sure who originally came up with it but it is your basic two tank system. It is documented well here. I’d rather not try to reproduce it. The plumbing is actually quite tricky for the diesel filter returns.

http://www.wvodesigns.com/blog/wvo-info ... onversion/

The issue comes from the fact that Mercedes diesels push fuel through their fuel filter rather than suck fuel through it like a gas car. So if you just put in a second tank with a return and delivery pipe you will run your fuel through the same filter.

What people wanted to do was have two tanks and two filters. This cannot be done when the fuel pump is between the tank and the filter unless you want two pumps which is mechanically difficult since the pump is driven by the engine. The way it was solved was reorganizing the system where the pump is placed downstream of the filter(s) like in a gas car. You reconfigure so you suck fuel through the filters. Once this is done you only need one pump and a selector valve that chooses between the oil filter and tank or the diesel filter and tank.

This is all complicated by the return circuit. The unused diesel in the car must be circulated to the tank (like on any fuel injected car). Mercedes has multiple circuits that merge into one tube that leads back to the main diesel tank. A conversion needs to cut off this flow and divert waste oil back on the recirculating path without pumping it back on the main tank’s recirculating line. Otherwise, if you pump your waste oil fuel back to the diesel tank it will overflow as you empty your oil tank into your main tank.

So in theory one would recirculate back to the SVO tank when on SVO. The issue there is multifold. First you’ll need an independent line to the vegetable oil tank. This line may need to be heated if you live in a cold climate. The heating requires two coolant lines so now you have four new lines going to the back of the car. It gets crazy trying to fit all that in.

Greasecar and others solved this by “looping the return” where the recirculated return fuel from the injection system is run back into the intake of the SVO circuit in the engine compartment. It is T’d in right at the switch valve that selects between the diesel and oil feed lines from the tanks.

But there is an issue with this that must be overcome. One of the advantages of a return line to the tank is it can purge air from the system. If an air bubble gets in the system it will eventually get injected into the engine causing rough running or a stall or it’ll get purged back to the tank through the recirculating line. But on the two tank loop back there is no recirculating line to the oil tank...because we cheated and didn’t want one. So if a bubble gets in there it’ll just go round and round and eventually get injected into the engine and likely stall the car.

So an additional valve needs to be installed to temporarily purge return oil to the diesel tank. Lost yet? This is opened momentarily till all air is purged and then sealed off. This line needs to be monitored because leaving it open will overflow the diesel tank and letting it accumulate air will cause a stall. If all is good you purge air and never open the valve again till you change filters or run out of fuel accidentally and suck air.

The return lines on MB’s existing filter are tricky too. It has four ports unlike a simple two port VW system. These paths need to be plugged for the loop to work hence the solid bolt described in the link above.

This is why I didn’t want to do a full out howto on this. It is tricky to plumb. The best way is download an old copy of the Greasecar for Mercedes manual online and use their diagrams. The above referenced site has all the information but it isn’t obvious.

After I converted one car that became my diagram for further conversions. I’d literally pull my car alongside the car I was converting and copy it.

Additionally I don’t know if the two tank looped return is the best design. It is a compromise for using cheap hardware and minimizing plumbing. It solves some problems but creates others. I tried “inventing” my own fair climate design but it had other reliability problems and I never finished it. Resolving the problems involved a custom valve design that I didn’t care to take on.

Sorry I cannot do a full writeup but you can get the gist of what is going on from this post.

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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by gilyermo »

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Last edited by gilyermo on Thu Nov 26, 2020 6:41 am, edited 1 time in total.

ThriftyRob
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by ThriftyRob »

Hristo Botev wrote:
Mon Nov 16, 2020 1:16 pm
@alphaville: It's tempting, certainly. Sell the truck (and it's ~16mpg) for ~$42K and buy a used Prius (40+mpg?) for ~$6K; that'd pay for Catholic school tuition for 2 kids for 2.5 years. DW is hoping we get an Airstream sooner rather than later, though; so it's going to be a tough sell. That said, her priority (mine also; but it's really the driving factor for bringing DW around to the ERE mindset) is the kids' schooling--so, maybe?

Is what the Prius has going for it is that it's battery is charged by the gas engine, as opposed to something like our old Leaf, where the power comes from coal/natural gas? I've only ever heard people complain about their Prius, so I don't know. That said, if I had to guess people complaining about the Prius is because it lost its smugness appeal when the electric cars became a bit more mainstream.
Funny you have blogged this. Yesterday, after reading your post about collecting wood with your truck I was using Mr Money Mustache's app and a random post of his came up in which he wrote that only people who live in a mountain forest need a truck, etc. Fuel consumption and cost alone should be great reasons for selling it and down sizing. MMM advocates a tow hitch plus a trailer for hauling stuff that would go on the flat bed of your truck.

I drove a Prius rental from Tampa airport earlier this year. It was pretty good (my own car is a LEAF and it wasn't a culture shock) and cruising at 60 mph on the highways we averaged around 70 miles per gallon. I didn't see any demerits in using the Prius. If you have no alternative that to use a car, then use one with as low an environmental footprint as you can.

Hristo Botev
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Hristo Botev »

I think the selling the truck idea is moot. Some friends of ours who'd gotten on board with the Airstream idea along with us just pulled the trigger and bought one. It needs a lot of work but my friend is handy and wanted the project; which is to say we're probably still a few months (maybe years) out before their family is traveling across the country (Here's a good visual: https://www.youtube.com/watch?v=FxuLRkHn7rQ). But, it's cemented in DW's mind that an Airstream is just around the corner, and she thinks it'll be silly to sell the truck just to buy another one in a year or two when we get the Airstream. I'm not quite so convinced we'll be able to knock out our financial goals (kids' school and paying off the house) in a year or two, especially since we're starting to pull the trigger on some home reno projects. But, needless to say, we're not selling the truck. I've been compensating by driving even less than I was before, and when I do need to drive somewhere, I've been taking my in-laws' sedan, which as a V6 gets slightly better gas mileage than the truck (about 22 avg vs. 16/17). Meanwhile, DD is calling me a hippy.

Alphaville
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Re: ?s about the Veggie Oil Diesel Conversion Thing

Post by Alphaville »

Hristo Botev wrote:
Mon Nov 23, 2020 8:18 am
Meanwhile, DD is calling me a hippy.
if you must escape that characterization just charge her the cost of each car trip. ;) :D



eta: it was probably a good idea to not rush the truck sale either way, regardless of long term outcomes (sell/keep/something). just take time to mull over options. and if you can garage it for most of the year, insurance is low. maybe 6 months or a year from now things will look different.

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