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layback40 · #**136** 11-11-2010, 02:56 AM

Army,
Your fuel purity should be fuel composition.
Much of the mix in WVO is pure enough, it is just that chemically its not a suitable fuel for a high speed diesel motor.
The composition variability is that great that when WVO is used as a raw ingredient for bio diesel production, its necessary to test each batch for its acid number & vary the recipe depending on the result.
The first thing that needs to be realized is that WVO & VO are not "oil" like diesel or engine oil. WVO & VO are triglycerides. Their chemical as well as physical properties are different to that of diesel. A part from viscosity, their combustion properties are much different. We are comparing a saturated hydrocarbon with a variable composition triglyceride that may have already been partly thermally cracked. The molecular weight of the triglyceride is much greater than that of the components in diesel. The glycerol back bone of the molecule has very poor combustion properties & in bio diesel production, it is removed & discarded. This is the main factor in bio diesel becoming a suitable fuel.

Triglycerides can be made to work in a low speed (400 ~1000 rpm) compression ignition motor. There have been many designed over the years for such fuel. With a high speed diesel like we have, the triglycerides cannot burn properly in the time available as it can be as little as 1/10 that for a low speed motor. Added to this WVO or VO are able to polymerize by a number of means, this is how the varnish forms. Heat & high pressure catalyze the formation. Hence we get stuck rings and other problems.
One of the reasons that there has been little if any proper testing & research is that the basic chemistry involved shows that there will be a problem, so no appropriately educated people want to have anything to do with it.
Why would you want to undertake a trial that is technically flawed?

If you wish to simulate the effect of triglyceride use in a high speed diesel, you could mix 1/2 a pint (300ml) of polyester resin ( the liquid resin used to repair fiberglass) with your new oil each time you change it, after say 10 changes, if the motor is still running, you could pull it down & examine the damage. A crazy futile exercise.
The panacea of water injection is not that new, steam/air de-coking of pyrolysis furnace tubes has been a standard procedure for many decades. It works well to remove unwanted by-products of the pyrolysis process, probably these by-products could have similar properties to the varnish from WVO/VO use.

Its probably time to put this thread behind us all.