I've often heard critics of alternative fuels complain that those who experience problems along the journey rarely return to admit their difficulties.

Well, here I am. I have had problems and I'd like to tell you about them.

I got an '84 F-350, 6.9 IDI, a few months back. This is a documented Navistar rebuilt engine with just over 20,000 miles on it since the rebuild (that's the main reason I found this truck so attractive). The previous owner told me that a while back he had experienced some smoking and power loss, so he replaced the return lines and tees and the problem went away.

I had been running my '83 Mercedes 300SD on a mix of about 50/50 centrifuged (20+ passes with a 120 GPH pressure-driven centrifuge from PA Biodiesel Supply) waste motor oil, which was a mixture of various weights, some ATF, maybe some other stuff too. No idea whether the oil was all non-synthetic or some of it was synthetic. The Mercedes had been running on this mix for months without any major problems, just smoking when cold -- but that's pretty typical for an old Benz, even on pump diesel.

So, confident I had a fuel that worked, I put it in my truck. And it worked well for a few weeks.

But one day when I was driving home from work, the truck lost power and started smoking. I pulled over and the engine died. I restarted the engine and things were back to normal. It concerned me, but didn't happen again the next day.

Then the same thing started happening more frequently. It got to the point where I couldn't run the engine for more than five minutes without it losing power suddenly, smoking like crazy, and dying as soon as I put the clutch in. Restarting it made things return to normal, for a few minutes, until it would happen again.

I went through a good amount of troubleshooting (see the thread for the details), and ultimately I came to the conclusion that it was my homemade fuel causing the problem. Switching the truck back to clean pump diesel makes the problems completely go away.

So, I don't know. Maybe there was something in the oil my engine didn't like (synthetic oil, perhaps). I don't think I've done any damage to my engine, but of course without taking things apart I couldn't say for sure.

Just a cautionary tale. From what I've heard, it's probably best to know exactly what is in your oil and avoid any synthetics. I thought I had centrifuged mine sufficiently, but perhaps not.

I'm getting out of the game, since I have to move to a house where I'm not allowed to have any of the equipment. All that stuff has gone to a friend of mine, so I'll try to report back occasionally with his progress.

 

thanks for the update on your situation! so far i have 3600 miles and about 40 days of WMO experience, running only 10%, and so far so good. i did some research around here and found that running too high of a concentration WMO is prone to causing problems, which is why i chose 10% and plan to stay there.

let this thread serve as a warning to all newbies to keep your mix conservative and be smart about what you pour in your tank!

flainn, it sounds like you probably got your fuel cleaner than i do with my blue-jean filter, so i bet the only problem is the concentration of oil you're playing with

 

Yeah, could be. Sticking to a lower concentration would probably at least reduce the number of problems you may encounter, if not eliminate them.

For me, though, if I can't run a high concentration of WMO (i.e., save significant money on fuel costs), it isn't really worthwhile. Collecting, storing, centrifuging and blending WMO involves a lot of effort and potential mess, and to run only a 10% blend the payoff isn't there for me.

 

for me, i drive 40k miles a year, and produce a conservative amount of WMO in my auto mechanic business. i had 3 barrels full with the intent of a waste oil furnace in my home shop, but then decided to use it for fuel. with a simple blue-jean filter, i'm investing almost no money and not much time, so 10% savings on fuel ain't a bad deal.
but we each have our own needs and situations.

 

Why bother running 10%? I would keep at least 50% in the tank. I never noticed a difference at 50%. I'm running 75% without any problems.

 

well blind driver, i have a limited supply of WMO, i drive a lot of miles, and i depend on my van for my business. i'd rather be a little too conservative and still save a little money than push my luck.
i've done a lot of reading around here, and it seems the general consensus is that running too strong of a mix is much more prone to causing problems than running a conservative mix. so for me and my needs, i'm staying conservative

 

You may have done it and just didn't write it in your post but did you change the fuel filter after the truck started misbehaving?

Also, what was the ratio of WMO that you were using? Did you add any gas to it prior to/after centrifuging? Thanks for posting your results and please keep them coming.

 

id hope he changed his filter but its hard to tell

 

I am thinking of runing WMO in my 91 e350 however i am worryed about phase separation that can explain the trouble he had.. i haul fuel for a living. Gas, diesel,kero,jet ect.. WMO will have PH differances than the fuel you mix with it..fuel is held together with a chemical bond. thus you can get separation in the tank. the problem would be greater with higher concentrations of WMO cooking the fuel in batches adding PH modifers might help???

 

You are seriously over thinking this.

The sloshing in the tank will keep everything mixed. Even if things separate a little bit, it won't matter as long as your fuel pressure is good. Too thick of a mix and your fuel pressure will start to drop off due to restrictions in the fuel filter.