A buddy found a source for SVO (corn/soy blend) for $12 a 16 liter (4-1/4 gallon) cubie - that works out to about $2.80 a gallon.

I'm thinking of buying some and blending it with diesel over this summer. I figure one cubie per 20 gallon tank - basically 20% SVO and 80% diesel. With summertime temps, anybody think there would be any problems with this mix? Anything I should add to it (10% gasoline, a little DieselKleen, etc.) to help it stay homogeneous?

Any danger of long term damage running a 20% SVO blend in my F250?
What about in my old 300CD Mercedes?
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You would be better off making biodiesel, but since your truck is an older one, it should be ok. Just keep up with the filters. Same for the mercedes.

Before you blend it though, remember to filter it a few times. Filter way down.

 

Filter? New, food-grade oil? Why would I need to filter it? What would I be trying to filter out of it? There shouldn't be anything in it that needs to be filtered out, should there?

I don't understand...

 

Oh, sorry. If it's new, dump it in. I would burn it in my powerstroke.

 

LOL! No problem man! You had me going for a minute there though!

 

Some folks advocate blending.
There are; however, problems inherent in doing so. The two liquids, #2 diesel and VO may well seperate into layers and you could end up burning unheated straight VO. That can result in coking which can lead to engine failure, it can also lead to fuel pump failure.
If you want to run VO the two best methods are convert it to BD and use it like #2 or convert your truck to straight VO, this involves two fuel tanks and a heater for the VO.

Your 86 IDI engine will do well on VO, if you do it right.

 

My first order of business is going to be seeing how well the oil mixes (and stays mixed) with diesel. Here's my plan on that. Since I want to try running mine as a blend instead of converting it to bio, here's a test I'm going to try. I'll mix up six 1-quart jars. Two at 20% SVO, two at 40% SVO, and two at 60% SVO. I'm going to add DieselKleen at the recommended 1:400 ratio to one each of the 20%, 40%, and 60% blends (a suggestion I read on another site).

Then I'm going to leave all 6 jars out on the back porch overnight for a couple of nights to see if there is any separating, clouding or any other significant difference between the blends with and without DieselKleen. Then I plan on storing them in the fridge for a couple of days and see what kind of difference THAT makes.

The end result I'm hoping for is to be able to run at least 40% and maybe even 60% SVO - either with or without DieselKleen treatment. That would be the ideal, but if there is any separation or cloudiness of the 40% or 60% blends - even WITH DieselKleen added, I'll fall back to my original plan of running it at 20% blend. If neccesary, I have a couple of ideas on how to make it work regardless. Here's what I'm thinking of doing...

What would you think of using some of that skinny copper tubing - the kind that they sell for connecting the cold water dispenser in your fridge to your house's plumbing (1/4" ID or so) - to make a little heat-exchanger coil "pack" to mount on the lower end of the injector lines, in the area where they are all side-by-side (down near where they exit the pump). Then connect it to the cooling system to flow hot water through it. I'd also install the electric injector line heaters (which are only 6" elements) with the jumper wires (like the ones on the fattywagon site) to the injector lines - but install them up close to the injectors rather than where the injector lines come out of the pump (hence the need for jumpers between the heating elements).

Apply the same principles to the incoming fuel line to the IP. Install an electric glowplug-based inline heater on the IP fuel supply line right up close to the IP, and install a coolant heat exchanger (maybe hose in hose OR a heated filter) a little farther away from the IP.

At startup the electric injection line heaters would be allowed time to warm up the lines and the glow-plug heater would pre-heat the incoming fuel. I'd connect both electric heater systems to independant thermal switches to turn them on and off to regulate how much they heat the fuel in the lines and going into the pump. I'm thinking set the one for the glowplug heater at around 140*-160* F, and the one for the injectors around 160*-180* F, for example.

That way the electrics would do the whole job of heating the oil until the engine coolant gets hot enough to heat the injector lines and pre-heat the IP fuel supply, then as the coolant based heating elements warm up the electric heaters would turn off. If not completely then at least they would cycle off for longer periods of time - due the coolant systems pre-heating the fuel.

If the lift pump being able to pull the higher viscocity veg oil from the tank is a concern, maybe I could add a cheap electric fuel pump inline with the mechanical lift pump to "assist" with moving the thicker cool oil.

My main concerns with the injector line heaters AND the glowplug heater is that if they are on full-bore all the time then 1) they add a constant load to the electrical system, and 2) constant operation at full temp just about has to shorten their lifespan. I'm thinking that with temp control regulating their max temp, and shutting them down (at least most of the time) once the engine is warmed up it ought to make for more reliable long-term operation.

I don't like the idea of heating the oil in the tank for a number of reasons.
1) complexity and difficulty of install
2) expense
3) polymerization of oil in the tank
4) increased risk of algae bloom (it likes warm environments)

So, what do ya' think of this as an idea for a system?

Also, keep in mind that although I may try this on my F250 too, I'm mainly interested in doing it with my 84 Mercedes IDI, and probably only during the summer (and maybe fall) months

 

The problem with your plan is that #2 and VO are miscible enough to not seperate into distinct layers. There is a good chance you will have a gradient with 90/10 VO/#2 at the top and the reverse at the bottom.
Under those conditions you will not be able to tell if they seperated.

 

Hmmn, interesting. Of all the sites I've posted this question, and all the reading I've done, you're the only one who as expressed that concerned or described anything like this as a potential problem. Do you have any more info or references to this phenomenon that I can read up on? Any specific cases you know of or could point me to?

With all the jostling and sloshing around in the fuel tank of a daily driven vehicle, particularly a Mercedes diesel (arguably THE most resilient engine on the planet) do you think this is really an issue to be concerned about?

No insult intended, and I really do value your opinion, so please don't take this the wrong way, but I also have at least gotten the impression that you are a big advocate of making bio, so I have to wonder if that might bias your opinion against blending?

Regardless, I was wondering what do you think of my proposed startup-on-electric-heat-that-automatically-transitions-to-coolant-heat system that I proposed? See any drawbacks with it?

From what I've seen, people who buy the inexpensive "veggie kits" are often dissatisfied, and those who buy a really good kit spend a fortune for it. Most "good" kits include a heated tank for the vegetable oil, and as I said before I don't like what I've read about heating the entire tank of oil for the reasons I listed above.

As an engineer, the idea of designing my own system that will work reliably for a minimal investment is a challenge that I find very appealing. Truth be told, even if I were to screw it up and waste my engine, by the time it does significant damage I'll have saved enough money at 2 bucks a gallon to buy 3 or 4 junkyard engines - or maybe even a reman.

Of course I don't intend to let that happen because I will be monitoring/experimenting and improving on the system as I develop it. I want to start with a low concentration blend and gradually increase the percentage of SVO as the system develops and proves it can handle it.

My goal is to have fuel (blended or eventually maybe even straight SVO) going into my pump at around 160* and hitting the injectors at around 180*. And I want it to be able to work as a single tank system, requiring minimal modifications that are easily reversable. I think that the electrical-heating-switching-to-engine-coolant-heating system may be a suitable way to accomplish all of those things. I guess we'll see...<!-- / message --><!-- sig -->

 

Mostly a background in organic and biochemistry that raises little red flags when trying to mix liquids of such disproportionate molecular size and weight.

There are adamant proponents of blending out there. They concoct all sorts of exotic mixtures of VO, #2, gasoline, kerosene, hydraulic fluid, automatic transmission fluid, naphtha. benzene, and etc..
I make the same admonition to all of them. You are gambling the life of your engine on an unproven potentially damaging mixture of fuels to save a few $$. There are other safer ways to achieve the same goal. It's your engine, the choice is yours.

 

Most of those are working with used oil.

I thought the biggest concern when using new 100% vegetable oil was gelling. It wouldn't be a problem where I live, lol, but it sure would be for the OP.

Is coking still an issue using new stuff?

 

OK, fair enough. Like empiretc pointed out, most of them are starting out with used - versus my NEW - oil, so it is a bit of a different ballgame. It almost sounds like you're trying to give a a "better safe than sorry" sort of warning. One of those "this isn't likely but you need to be aware of the possibility - no matter how remote" kind of legal disclaimers. Am I readng you right on that - or do you think there is a truly significant risk of the oil/diesel separating in a manner that isn't readily discernable (an idea I'll refer to as gradient separation) - or are you only pointing out that it is at least possible?

You mentioned the two fluids having "such disproportionate molecular size and weight" as part of the reason for your concern. I think I have a basic understanding of the role that plays in mixed fluids separating (specific gravity, etc.), but I don't quite understand how they can be so different at the molecular level, and only partially separate. It seems to me that either the molecular sizes and weights are significantly different - and they will separate fairly quickly and distinctly, or the molecular sizes and weights are similar enough that they will remain fairly well mixed.

As I've always understood it any given single-weight petroleum-based oil will also have a fairly large range of variation in molecular sizes (and correspondingly molecular weights), and (disregarding additives) the larger the molecules (carbon chains) the higher the viscocity of the oil. Conversely the smaller the molecules the lower the viscocity. Yet if you mix 30 weight and 90 weight they don't separate to any great degree in any reasonably short period of time. Certainly not in a matter of a few hours. Even if you mix something as low viscocity as gasoline with 90 weight, they still won't separate in a short time. Admittedly the molecules of two petroleum fluids are chemically more similar than a molecule of petroleum and a molecule of vegetable oil - due to the glycerol (glycerine?) chain in the vegetable oil molecule - but in terms of viscocity and molecular size and weight aren't vegetable oil and diesel more closely matched than the example of gasoline and 90 weight? I'm just trying to understand the principles behind your idea about what I'm calling "gradient" separation.

Obviously there is always SOME risk - but such is life. I'm at least taking SOME risk of getting run over every time I step off the sidewalk too, right? Like I said, from reading your posts I've come to respect your opinion, I'm just trying to get a better "feel" for what level of risk you believe there to be.

Also, is there some reason you aren't commenting on the fuel heating system I'm proposing? I'd really appreciate it if you would least give me your opinion on the merit of the concept and/or any potential pitfalls/problems you can foresee with it. So far no one has commented on my proposal - here OR elsewhere. Either it is so well thought out no one can find anything to critcize, or it is so poorly conceived that no one knows where to start...

 

It is enough of a possibility that I would not consider running a blend in my truck.

They have enough chemical similarity to make them partly miscible; however, a molecule of #2 is a long non-polar saturated hydrocarbon chain averaging 10 to 15 carbons in length while the VO molecule looks like a capitol E with each horizontal arm being a long slightly polar usually unsaturated hydrocarbon chain averaging 10 to 14 carbons in length. As you can see the VO molecule is at least 3 times the size of a molecule of diesel. It is more compact because the hydrcarbon chains are held tightly together and VO is significantly more viscous than #2. It is because of the chemical similarity in the arms of VO to #2 that they are partially miscible but the physical properties will tend to seperate them.
I have talked to people that have run "jar of blended #2 and VO on the back porch" experiments and they are mostly unable to visually detect layering. The potential for a gradient is high enough and the consequence of burning unheated VO is significant enough that I dont want to risk my $10,000 powerstroke with out proof that it is safe.

Actually gasoline and 90W oil are much more closely related than VO and diesel. I have already described the difference between VO and diesel but 90W molecules are just a larger version of a molecule of gasoline the most significant discrimiating property is viscosity.

I have opted for the BD route thus I know very little about the intricacies of running VO. All I know for sure is burning unheated VO is a recipe for disaster. If you really want to pursue the Pros and Cons of unheated VO contact the forum sponser, Vegistroke. I know he can answer your questions better than I.

 

Me neither - if I were driving a $10k PowerStroke! Like I said, I'm more interested in burning this in my DD Mercedes IDI - which is worth around half what your PowerStroke is. Plus it has an engine with a reputation for being FAR more tolerant of "less than perfect" fuel, and can easily be replaced for under $500...

Is there any evidence that the gradient separation phenomenon actually exists, or is it theoretical? You refer to others having been unable to visually detect it, but was it then shown to exist in those cases - or could they not see it because it wasn't there? Are you aware of any studies or test data? Any other examples of it in other liquids? I'm not saying it doesn't exist, but I just have some difficulty getting my head around the idea of it being a steady state condition. Short term, sure. During the process of separation of non-miscible liquids I have no problem understanding how a gradient would occur. But left sitting for any significant amount of time and I can't see how any two liquids mixed by simply pouring them togther could arrive at a stable gradient like you are referring to.

So the VO molecules are roughly the equivalent of three of the #2 diesel molecules joined in a parallel configuration? I'm guessing the "backbone" that joins them into the "E" shape is the glycerine molecule?

Well, yeah, obviously the gasoline and 90W are more closely related - since they are both petroleum distillates. That really isn't the question I was asking or the point I was making. My question was more about the dissimilar size and weight of the molecules, and the role that plays in separation - particularly the "gradient" type of separation you suggested. If a molecule of #2 is 10-15 HC pairs long, how many HC pairs (on average) are there in a molecule of gasoline? How many HC pairs in a molecule of 90W oil? I'm guessing that based on viscocity (which I've always understood to be primarily a function of average molecular size - though configuration plays a role as well) the 90W molecule is at least 3 times larger than the gasoline molecule. Is that assumption incorrect? Yet they don't separate at all when mixed, right? So I guess I don't understand why the veg oil and #2 would do so. If anything the higher viscocity of the veg oil seems like it would hold the #2 in suspension better - almost like an emulsion on a molecular scale.

Thanks for the referral, and I will contact him. But let's all be honest here. We all have our biases. As previously mentioned, I get the feeling you may be at least a little biased against blending because you're such a proponent of BD. Likewise I expect Vegistroke is going to have his own bias as well. Most likely towards straight veggie since that is his business - which will also bias him against blending.

 

Hey Cheaper. I think your heating ideas are great. Thought about some using some of your ideas on my Benz.