First a little theory tested and backed up by Idaho State Uni testing and research, which has been verified by my own 'basic' testing

The myth about veggy and to some extent BioDiesel, is it burns hotter....

Lets put That one to bed once and for all

It does NOT.....

What gives this impression is the higher NOx values sometimes found when these fuels are used, during early developments and testing in the 80's.

The Truth of the matter is that they take Longer to burn, and hence more chance of NOx generation...

IF the fuel takes Longer to burn, it will achieve its peak pressure later than intended during the 'working-stroke' when burned in an engine using standard Diesel-Fuel timing settings....

We've all seen the effect that mis-set Diesel injection timing can have on a diesel running std fuel. So, when you change the fuel, you need to change the parameters in which its burned to compensate, or in some extreme cases, what Lance says above 'could' occur, but this usually only happens in extreme circumstances OR with Direct-Injection type engines foolishly run on single-tank 'conversions'...

The answer for our Pre-chamber/Indirect-injection engines is to Advance the Point-Of-Injection, by 4 degrees, maybe a degree or two plus or minus depending on smoke K value testing, by F.A.S--The least smoke, the better the combustion, and better combustion all things being equal means more power/better economy.....

On our OM61x series of Pre-Chamber engines its neither needed or beneficial to increase the opening-pressures of the injectors, as was commonly thought. In fact it has a detrimental effect as this would delay the point of injection, (Effectively Retarding the timing) as the pump would have to achieve a higher plunger-movement and a higher pressure to open the injector. The 'spray' isnt finer either on an injector set a few tens of bar higher than intended, BUT its opening time is delayed and most importantly its Rate Of Delivery is slowed, thus lengthning the injection event adding to the 'delay' in fuel delivery. It will also deliver Less fuel than intended....

What IS important, is the quality of the spray-pattern achieved. A worn injector can and will work reasonably well when first used with veggy-oil as fuel.....For a time, usually around 500-800 miles, before the wear in the seat/needle/pintle causes coke build-up in the pintle and hole areas, with degradation of the spray-pattern. Smoke and poor starting result

A New nozzle which has no wear does not deteriorate in this way, but maintains a good pattern and atomisation for tens of thousands of miles

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....