What Causes a Sooty Engine?

[Seangie]

There seems to be a bit of soot coming out of my engine.  Its always done this and I had just assumed it was from the muffler. 

Since replacing the muffler its still putting out soot.  Enough to cover the front bumper of our tow vehicle in a fine silt of soot.

Just wondering if this is normal and if not, what causes the engine to put out soot and what can I do to help prevent it.

Thanks Guys.

-Sean

[TomC]

Lack of air will cause sooting. Main culprit-dirty air filter. Next is lazy injectors with worn out tips not giving a sufficient spray pattern. Bad fuel modulator (mechanical engine), allowing black smoke on start up. I get sooting also-even with up exhaust. This is why 2 stroke engines are not used anymore.
Yet the next engine I believe to come out is a 2 stroke-but opposed piston engine by Achates engine company. They have a 3 cylinder that puts out 300hp and 1100 torque-so a 5 or 6 cylinder would be perfect for bus and truck. Opposed piston is minimum 20% more fuel efficient. Good Luck, TomC

[Iceni John]

Yet the next engine I believe to come out is a 2 stroke-but opposed piston engine by Achates engine company. They have a 3 cylinder that puts out 300hp and 1100 torque-so a 5 or 6 cylinder would be perfect for bus and truck. Opposed piston is minimum 20% more fuel efficient. Good Luck, TomC

The venerable Commer TS3 opposed-piston 3-cylinder diesel engine of the 1950s and 1960s only produced half as much power, but it ran cleanly and sounded great, sort of like a Detroit 53-series.   I cannot recollect seeing much exhaust smoke from them, but after all these years my memory may be less than 100%.   One neat thing about them was that they had only one crankshaft!

John

[eagle19952]

running cold can contribute to this also. the good news is that the only detriment is to your toad...maybe a bra

or be grateful you are not towing the Benz....

[Scott & Heather]

He said he has a fine silt of soot on his toad. That's a lot of soot


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[blue_goose]

Don't just turn it down.  Turn it down and out as far as you can.   
Jack

[uncle ned]

Jack  do you think he has the Jarra  mentally in his engine. 

The bigger the injectors  the better.

lol   miss the old guy

uncle ned

[luvrbus]

It's the fuel to air ratio thing, me I would pull the blower and check to see if the aftercooler has a buildup on the fins JMO

[TomC]

Yes the Commer had one crankshaft for opposed pistons. But because of the rocker connecting rods, horsepower output if limited to lower power outputs. Higher outputs have to use twin crankshafts. Good Luck, TomC

[Geoff]

The 2-stroke Detroit requires a certain percentage of back pressure from the muffler in order to run right.  Oversized injectors, a free-flowing muffler (no back pressure), high altitude all cause black soot if you know that otherwise the engine is running like new and not worn out.  This is to add to what already has been mentioned.

--Geoff

[Scott & Heather]

I always assumed that the two-stroke didn't require back pressure, but did have a maximum back pressure rating. From everything I've read in all my diesel magazines, the less back pressure the better. But honestly I'm not a diesel mechanic, so I really don't know what is fact or fiction


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[TomC]

The back pressure thing usually applies to a natural engine. On turbo engines the turbocharger gives a nice back pressure. So running straight exhaust on a turbo engine usually decreases black smoke. Good Luck, TomC

[lostagain]

From my experience, the less back pressure, the better. The exhaust gases need to get away from the combustion chambers as easily and quickly as possible. Also the turbo is more efficient without the back pressure of a muffler, or too small a tail pipe. So it comes down to how much noise you want to put out the exhaust pipe. Mine with turbo and resonator, is louder but tolerable, but runs a lot nicer and freer, and cooler, than with the muffler.

JC

[luvrbus]

The DD engineering bulletin # 134 explains the back pressure deal,but Sean is good with the 90 bend.I think his problem is the Farr air cleaner and it's location on a Eagle.I have replaced a few of those with a 1350 CFM ECO series filter and it made a big difference on a 6v92TA a little harder to change as the FARR on a Eagle is about as easy as it gets 

[Dave5Cs]

If you only let your engine associate with upper crust engines from rich neighboring coaches that will happen.
Oh sorry you said Sooty. I thought you said...... never mind!...
Dave