Originally Posted by
Blknight.aus
sure...
Yes at normal temps and pressures (lets say TDI300 engines) 100% pure and correctly refined bio IS the better diesel in all respects full stop end of story on that count.
But... When you step out of the hypotetical perfect world Bio Aint Bio when its got water suspended in it that hasnt been dried out, ethers still in solution that havent been washed out and imperfections in the oil from using burnt oil.
Now in a normal situation low to medium pressure injectors (relatively speaking here ALL injection is high pressure) the bio is great, and the contaminants arent a problem But once you switch over to the High pressure injectors (21K+ psi) you start to run into problems.
First off the impurities cause little Islands in the oil between the moving part and the oil is expelled from the high points (lateral experiment;squeeze your thumb and forefinger together really really hard and put it in water, pull out, dry hand and when you pull your fingers apart the middle of the pressed together parts should be dry) that lack of lube causes problems. The knock on effect of this is if these contaminates causes an injector to fail to seat you will get dribbley injector or even worse a fail to close letting residual fuel pressure drain into the combustion chamber potentially hydraulicing the engine (not to bad for pots 1-4 but #5 doesnt have a glow plug you can pull out to vent it and I bet it will be the #5 that does it just to annoy you)
Secondly the bio can attack some seals and the lubricity of it when its warm and under just a little pressure means it can leak past some seals that dino diesel just wouldnt have, not so much of a problem on a TDI as the injection pump is only at about 15psi or so max and the entire fuel system is external to the engineso you can see the problem and fix the leaks.... On a TD% however about 50% of your fuel system is internal to the engine, get one of them leaking and your lube oil gets diluted with fuel. That'll kill you in one of 2 ways, by diluting the lube oil to the point that the engine siezes OR by leaking out the turbo seal/ venting out the crankcase ventilation into the inlet causing a run away (havent heard of that one yet but on paper its plausable)
The last way is with the effeciency with which Bio cleans. All the crud that was happilly adhered to the internals of your fuel system will no longer be so and you can get all of the problems from the first point but more likely will be the death of the fuel pump from having to pump the equivelent of gravel..
All that said...
I know of people who have run their TD5 on bio and are still doing so with no problems that people running dino arent having. But at $1700 odd for an injector, $1k for a pump, who knows how much to redo the head if it gets stuffed and how much? for a new donk if you get a run away. Bios not for me in the TD5...
It might be doable in the new ford donk But I havent yet specked that one out and dont own one so Im not likely to....
I do know that the old 2.25 runs just fine on dewatered and filterd cooking oil. did that in townsville for about 2 months as an experiment.
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