Alternative Fuel for 6.2

[darville]

One of the reasons why I bought a diesel was for the option of running alternative fuels. I am looking some advice from people in the know:

1. Does anyone have any real world experience running alternative fuels?
2. What type of fuel besides veggie oil?
3. What are the legit concerns with running alternative fuels in a diesel?
4. Can you run these fuels in a single tank operation?

Any input would be greatly appreciated. Thanks.

[convert2diesel]

To answer your direct question, what is it that you intend on running in this engine? For the obvious alternatives, here are my experiences:

1. Bio-diesel. If properly made and filtered, these engines love bio-diesel. Have put on over 100K, running anything from B5 (winter months) to B100 in the summer. This was all on bio-diesel I made in my garage. Fuel mileage is down about 3% from #2 but power is up due to allowing for slightly more advance. Cold weather operation takes some planning, as does the feedstock. For the most part I used canola and as a result could get by down to about freezing. After that you have to reduce the concentration till you hit about 5% in the middle of February.

2. Vegetable oil. Flat out, it doesn't work for long. Three reasons for this. One, if you don't get it thin enough, the timing goes all over the map. The Stanadyne pump relies on differential pressure (transfer pump pressure and bleed off pressure or dome pressure) to adjust the timing. Anything thicker than #2 by any significant amount and the advance mechanism goes all wonky. The second is heat. In order to get the straight stuff thin enough, the fuel is entering the pump is coming in at about 160F. That is just too hot for these pumps and the wear factor is unacceptable at these temps. The design is such that they are depending for a large part on the incoming fuel to "cool" the pump. Can't do that if the fuel is coming in at engine coolant temperature. The third reason is the money shot. The boiling point and vapour point of fatty acids and glycerin are different. There is sufficient heat of combustion to cause a separation between the two. The long chain fatty acids will normally combust but the glycerin is a different matter. Unless the temps are high enough to ignite the glycerin component, than it either does not burn and stays in one piece, coating the pistons and rings with a hard black char or does boil but immediately falls apart leaving the carbon component in the cylinder. Same result...heavy build up on internal components. This will happen on all the parts from the injector tip, the pre-combustion chamber, the piston crowns and compression rings and lands.

In short, there is no free lunch. I am a believer in bio-based fuels but they must be processed properly. Anyone who thinks they can get away with pulling up behind Raunchy Rons and filling up their tank for free is dilusional. You might get away with it for a few months but the enevitable is going to happen. Over the years I have seen more money and time expended on "free fuel" when for about $1,500 or less, you can set up a good little bio-diesel processor.

If you insist on running straight veggie, the older Mercedes or Cummins with the inline Bosch pumps are better equipped for this task. Your still going to have to de-carbon the engine every couple of months and run the occasional tank of pure diesel to clean out the pumps but your success rate will be higher with these engines than the 6.2.

To date I have seen nothing else other than bio or veggie that will work. None of the snake oils or HHO generators work. In theory anything that burns can be made to work (I swear my old 300D Mercedes would run on wood chips if you could grind them up small enough) but in general, these engines are designed to run on #2. Anything significantly different and your asking for issues.

Hope this helps

Bill

[darville]

Bill, thank you for your clear and concise reply. By far this is the best explanation I have for why things work and don't work. Everyone likes to say that diesel will run anything but obviously they wont run for long if you use the wrong item.

As far as bio-diesel goes, do you have a recommendation for a processor? I know they are all not created equally.

My plan is to do bio from spring to late fall. I live in Atlanta, GA and we typically don't get too cold but you never know sometimes.