Better just stick to good ole #2 .

 

I'm lost... this might explain it more better. http://journeytoforever.org/biodiese...d2.html#cetane
Theres more that I can't find right now on the site. The page said to advance timing to "take advantage of the additional power". Will PM (msilbernagel) you when I find It. There is a lot of good info there... sometimes I might get the facts backwards Jethrro

 

Jethrro,

I did a quick Google of the site and found this:

To quote: "Timing - Optional: Retard the injection timing by 2-3 degrees -- this overcomes the effect of biodiesel's higher cetane number. The engine loses a little of the extra power you get with biodiesel, but it runs quieter and the fuel burns cooler, reducing NOx emissions. (See also NOx emissions and biodiesel.)" - end quote

This pretty much echoes what I was saying, that the higher cetane of biod effectively advances timing (when it burns relative to TDC - piston at top dead center).

Use these search terms: "Journey to Forever" advance timing cetane

Now, all the above and what I said earlier was related to the thread but not really addressing your original question of "why do I get this smoke" which others say is white - I think you said yours is grey.

If you search around you'll find various sites stating why a diesel will smoke different colors:

Black - over fueling, too little air
Blue - most likely burning (crankcase) oil
White - unburned fuel vapor due to cold engine, injector problems.

Look at what Cummins says about biodiesel:

Note that with increasing concentrations, the list of problems grows, and this one in particular jumps out (to me) as related to white smoke after the engine is warmed up - i.e. potential injector problems due to carbon/particulate build up and subsequent poor spray pattern (atomization poor):

Quoting from page 2: "Areas of concern when operating with biodiesel fuels include low temperature operability (fuel gelation, filter plugging), heat content (poor fuel economy), and storage and thermal stability (filter plugging, injector deposits)."

AND

"Biodiesel fuels contain residual alcohol from the esterification process, which can remove deposits from fuel tanks and lines causing filter plugging during initial testing. The fuel system should be flushed with this fuel before operation, and the fuel filters will need frequent replacement in the early stages of operation in older units." - end quote

Got an older unit?

Read the whole article - it should be a bit sobering. As much as I'd like to use B100 - it isn't without potential side effects and risks.

If enough people had the same symptoms as you, I might attribute the smoke to Cummin's reasoning - general characteristics of biod which are possibly incompatible with the engine's normal operating parameters - things like thermal instability leading to injector deposits, which in turn lead to poor atomization (spray), resulting in incomplete combustion (white smoke a primary symptom). It could be a bad batch (old or contaminated) started this by giving you the thermally unstable fuel to start the whole matter.

If it's just a few of you with white smoke issues, I'd lean toward:

Injectors already marginally sooted, and the combination of timing, timing changes due to biod's cetane (etc), cooler combustion (less BTU, earlier/faster burn), and increased viscosity (affects fuel pressure and spray patterns too) would mean that the particular combination of operating conditions in your engine make it an especially difficult problem for YOU.

OR perhaps you had older trucks with more stuff that got flushed into your injectors by a rapid switch to B100?

How many mods have you made? Aftermarket injectors? Increased fueling? Those are wildcard items too.

You could try retarding the timing a few degrees, but I'd look into injector cleaning first.

To test the theory, I'd try B2, B5, or B20 for a while.. along with Power Service Diesel Kleen (or similar) - and see if you can get it running smoothly. A little more certain would be to switch to dino completely, along with the PS/MMO combination so many use 3:1 - total of 16-24 oz per tank.

Then, RUN IT HARD for a few miles - towing is even better.

Whatever you do, satisfy yourself the injectors are clean and then try increasing the percentage of biodiesel up from zero and pay attention to the results.

That's my theory 'anywho'.

Let us know what you learn - because I for one am expecting biodiesel to increasingly find it's way into the mainstream as sulfur content goes down and lubricity problems (and toasted VP44s, CP3s, etc) go up!

Regards,

Mark
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I stand corrected. Thanks for the additional info. Jethrro

 

You're welcome, of course. What I hope is that somewhere in all that stuff you find a few ideas on how to identify and fix the smoke!

Good luck,

Mark
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Well done Mark!