fuel line replacement for biodiesel - Steel Soldiers::Military Vehicles Supersite

jakwi · 02-24-2010, 09:32

Has anyone replaced their fuel lines for biodiesel use?

It looks like there are at least two different sizes.

Anyway I was wondering if any one knows what size viton lines I'll need and how much, that stuff is expensive! I don't want to buy to much, but I definately don't want to buy to little.

thanks for the help,

M543A2 · 02-24-2010, 10:09

I am not totally "up" on the issue, but I have not heard of any farmers having to change anything on farm equipment to run it. It will be interesting to learn what the situation is.

Regards Marti

jakwi · 02-24-2010, 13:50

It depends on how old your fuel lines are. If there is real rubber involved, biodiesel will degrade, and eventually destroy them. Mercedessource.com has a fuel line that is biodiesel rated, but it's $18/8ft, so I didn't want to order more than I need, or the wrong sizes. I think some of it is 3/8, but I'm not sure about the other size.

Westex · 03-01-2010, 23:13

I got a real lecture over in San Antonio from a great (but expensive) shop when I had my injector pump rebuilt, concerning the problems with 'non petroleum' diesel fuel, such as biodesel. I am no chemist, but the info was not good for biodesel. In a nutshell, and this all according to the shop, biodiesel tends to trap moisture and suspend, or emulsify it. Oil, petroleum diesel, and Dinosaur fuel may trap moisture, but it does not suspend it. It gets removed by our first water trap. It is the centriguge effect of a water separator. Emulsify (or suspend) water within a fuel and a water separator has a harder time trying to remove it. A water separator, a good one, likes a glob of water and it can get it.

Anyway, in the same lecture, I learned that if moisture works it's way info the fuel, and gets into the IP, and gets injected into the combustion chamber, this is bad. The moisture acts like a kernel of popcorn, pops, and can damage injector tips, or worse. This is not so pronounced on our multifuel engines, as they are robust, but still? The lecture was rounded out by the maestro telling me that most of these issues are becoming very prevalent in the common rail engines in new production pickup trucks and what not. Water getting past them is actually blowing off injector tips, with obvious results (holes in pistons). My point in posting this is to just relate what I learned, so that the information might be translated to ?????? And oh did I pay for the IP rebuild. So I pass on the info.

Yohan · 03-02-2010, 09:22

What you post is interesting. I used to work in an emulsion lab making and testing mix designs for micro pave (a thin layer of bituminus emulsion that is layed on the road as a surface treatment). I'm no chemist by a long shot, but my understanding is that in order to make an emulsion, the materials have to be "forced" together. With Italian salad dressing, one can shake the oil and vinigar up in a bottle- instant emulsion. With bitumens in micro pave, I ran the materials through a mill that forced the product through a very small space over a spinning disc. I experimented with different additives that would slow and/or speed up the breaking process of the emulsion, depending on the materials used, road and ambient temp, etc. We used all manner of junk in the product. My boss would travel around the east looking for big storage tanks full of any kind of waste hydrocarbon. If he was lucky, they owner would pay us to take it away!

I know from distilling diesel fuel that there is water in it, but I don't remember the average percentage. How much more or less water would there be in biodiesel? Is there any part of the biodiesel making process that would cause the water to emulsify into the fuel? From what I've read, it appears that the more care put into making the biodiesel, the better quality product one gets.

jakwi · 03-02-2010, 09:52

Water in biodiesel is definately a concern, If suspended or emulsified water makes it to the ip it immediately boils out and does damage. As with all things though the product is a direct result of the amount of effort you put in.

When making good biodiesel you need to wash out the leftover catalyst and methanol out. This is comonly done by adding water to you biodiesel tank and putting a fish bubbler in the water later, which is denser and sits on the bottom. The bubbles carry the water up into the bio the methanol and lye are absorbed into it. (this is where the water and bio are forced together) Once the air buble hits the surface the water then drops back to the water layer. It is done this way as a method of gently mixing the water and bio so as to minimize emulsions.

After several washes the water comes out clean and you know that the bio is clean, but it is now wet, and so needs to be dried. This is typically done by circulating the bio and forcing it into a fan shaped spray head into the same container, after the water has been drained off. The fan shaped spray allows the water to evaporate off, some people also heat the bio in an effort to speed up the process.

Water content can be tested a couple of ways.

The first easy method is to place a cup of bio in your fridge. My Refridgerator sits at 33F. If the bio is crystal clear at 33f it is dry, if it is hazy then there is still suspended moisture.

The second is to heat the bio on the stove, if it starts popping and snapping, you know it is still wet, as the snapping and popping is the water boiling off.

If you take a shortcut and call it good enough, you'll pay the price with failures in your IP and injectors. These effects are more pronounced in newer vehicle because of the tight tolerances involved.

I think the reason many shops are opposed to home made bio is the lack of consistancy. Joe shmoe can go out and buy a cheap biodiesel processing kit, and make crappy bio. These cheap processors rarely include instructions on quality control testing, and as a result our friend joe happily dumps whatever crap comes out of his processor into his truck and is pleased and convinced that all is good when the truck starts and runs. He's later confused when a few months later his truck breaks down, the shop tells him biodiesel is straight from ****, and he swears it off telling everyone how terrible it all is.

Home made fuel needs to be made with full understanding that there can be no shortcuts, and realizing that just because it passed the test last time doesn't mean it will this time. QC tests need to be performed every batch, and if it doesn't pass don't use it as is. It is possible however to make really good clean dry fuel that can be used straight from 32f and up (or blended for lower temps).

Any way I'll end my rant here.

Yohan · 03-02-2010, 10:37

Thank you for the insight, jakwi. Would you say this water that could potentially be in a batch of biodiesel would be emulsified or just "there" like water sitting at the bottom of a gallong of fuel. Wouldn't the amount of H2O in the fuel would determine how well the fuel line water filter trapped? Just thinking out loud...

jakwi · 03-02-2010, 11:20

You know I don't know if emusified is the right word. I think, and I'm not an expert, that it is simply held in suspension, or possibly in solution. As I understand them fuel water separators use gravity to separate the water by giving it a location to fall to and by slowing the flow down enough for it to have time to fall out of the current. If the water is suspended in micro globules it might not have enough time in the separator to fall out. Maybe someone who understands the fw separator better can chime in here.

I suppose that if you were careless you could have free standing water sitting at the bottom of your biodiesel tank, but that would mean that you didn't drain it all out after the wash and that you didn't dry it enough.

I use a hydrosorb fuel filter after drying my fuel which will stop suspended water, if there is any water in solution it might pass through. Honestly I'm not even sure it's possible to have water in solution with bio, but maybe it is. My thought is if I fail to thoroughly dry my fuel the hydrosorb filter is my failsafe.

The other option for drying that I've heard of, but not tried, is to pass the bio through salt. Salt is not soluble in biodiesel, or any oil for that matter, but it absorbs the water, as a result drying the bio. The downside as I see it is if any salt makes it into your truck it's corrosive and could probably do some real damage to sensitive components.

Westex · 03-02-2010, 15:46

The place where I got my work done in San Antonio is called Diesel Injection. They have a web site: dieselinjection.com. My post above was not intended to knock Biodiesel at all; rather to just post on some interesting facets of it's properties. The use of the word "emulsified" was my doing, as by definition, emulsion is the suspension of one liquid in another liquid. The little jars this guy had with the various samples of diesel, biodiesel, and various contaminants, including water and beach sand to name a couple, were fascinating. I agree with you, Jakwi and you obviously are way ahead on knowledge of biodiesel properties.

A final note: what I took away from dieselinjection is that a good, really good water separator is a great investment. The guy at dieselinjection liked Racor products, but emphasized that having a glass bowl, or filter, where you could see any trapped contaminants or water, is a good thing. He also mentioned to absolutely stay away from chemical agents and or fuel additives that claim to 'disburse' water in fuel for the foregoing reasons.

Wolf.Dose · 03-02-2010, 16:32

I used Bio Diesel for about 4 years on my M1009 (before it died of rust). I always added 1:100 new engine oil for greasing the injection system (15W40, the cheepest awailable). The Bio Diesel was according to DIN/EN (Deutsche Industrie Norm / European Norm) and therefore I had no trouble except cold start below 5° Celsius.
I have no idea which minimum standard US Bio Diesel is following, therefore nothing can be said about using US Bio Diesel from my side. Homemade Bio Diesel for shure can not follow these minimum standards.
Fuel consumption with Germany Bio Diesel was about 10 to 15 % higher than with regular Diesel fuel, but the price was ok and so I saved a little.
Bio Diesel now in Germany is taxed and therefore more expensive than classical Diesel. So allmost nobody uses it any more. Buy the way, the regular Diesel fuel here in Germany contains nowadays about 7 % of Bio Diesel. To my knowledge the fuel line are no problems. Some older fuel filter models collapsed due to the used glue did not resist the Bio Diesel.
And, the pre glow harness of the 6.2 l Diesle does not like Bio Diesel, the green fuseable harnes plastic cover melts away in case of contact with Bio Diesel.
Wolf