Exhaust Soot

[xrocketengineer]

I have zero practical experience with diesels and I noticed today a lot of oily black soot on the left front corner of the frame and around the exhaust hole in the plastic grille after use (95hrs). I don't remember this happening before since I hose down the tractor after every use. The tractor had not been used in about three weeks with a couple of cold snaps in the 40's in between and the weather was around 70 degrees. It mowed fine with no black smoke except the usual little bit at startup and when changing RPM's. Anything to be concerned about?

 

[85Hokie]

I have zero practical experience with diesels and I noticed today a lot of oily black soot on the left front corner of the frame and around the exhaust hole in the plastic grille after use (95hrs). I don't remember this happening before since I hose down the tractor after every use. The tractor had not been used in about three weeks with a couple of cold snaps in the 40's in between and the weather was around 70 degrees. It mowed fine with no black smoke except the usual little bit at startup and when changing RPM's. Anything to be concerned about?

Diesels are unfortunately somewhat "dirty" in the combustion - despite all the technology it is still a burning of an oil, and soot is a byproduct of that, despite the great technology behind the engine itself.

I think you will have that almost always - however, are you running the machine at a "high" rpm? That is actually better for the soot than running at lower rpm. The newer models will have a regen feature that ramps up the rpms to burn off the soot on a screen - low rpms will actually create a bit more of the soot.
You do not have this feature - which is a good thing btw.

Here is a long but very interesting read on the mechanics behind diesels and how slobbering is created and somewhat prevented.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a151273.pdf

Despite this - there is a simple solution!!!! Got to the local big box store in the plumbing department.....get you a P-trap made of metal...... cut and clamp over the tip of the exhaust!!! Simply redirect the soot!!!

 

[dlsmith]

Here is the pipe I put on my BX2230.

 

[OrangeKrush]

Diesels are unfortunately somewhat "dirty" in the combustion - despite all the technology it is still a burning of an oil, and soot is a byproduct of that, despite the great technology behind the engine itself.

I think you will have that almost always - however, are you running the machine at a "high" rpm? That is actually better for the soot than running at lower rpm. The newer models will have a regen feature that ramps up the rpms to burn off the soot on a screen - low rpms will actually create a bit more of the soot.
You do not have this feature - which is a good thing btw.

Here is a long but very interesting read on the mechanics behind diesels and how slobbering is created and somewhat prevented.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a151273.pdf

Despite this - there is a simple solution!!!! Got to the local big box store in the plumbing department.....get you a P-trap made of metal...... cut and clamp over the tip of the exhaust!!! Simply redirect the soot!!!

View attachment 52822

I’ve got the new 2680.. does it have the regen feature? Thanks for the tip, I forgot about the soot!

 

[beckmurph]

I’ve got the new 2680.. does it have the regen feature? Thanks for the tip, I forgot about the soot!

No regen on your 2680.
Greased Lightning is a good product to remove soot on your loader frame.

 

[OrangeKrush]

No regen on your 2680.
Greased Lightning is a good product to remove soot on your loader frame.

Good.. thank you, I read about this and was hoping the BX did not have it.

 

[xrocketengineer]

Thanks for the replies. I was just thinking if there was something I should check for like water or something else since we had temperatures in the 90's and high humidity all along and then we had some drastic temperature changes like an almost 50 degree drop in one day. No freezing though since we are by the coast but inland got there.
Maybe the soot was accumulating and I did not notice as the "gray turned into black" on the frame.
I have been mowing with the engine running at 2700 RPM.
The "elbow" solution for the exhaust might be tricky with mine since the grille rotates up when opening the one piece hood.

 

[SidecarFlip]

It's keeping the exhaust system from corroding away.... be happy.

 

[armylifer]

Diesels are unfortunately somewhat "dirty" in the combustion - despite all the technology it is still a burning of an oil, and soot is a byproduct of that, despite the great technology behind the engine itself.

I think you will have that almost always - however, are you running the machine at a "high" rpm? That is actually better for the soot than running at lower rpm. The newer models will have a regen feature that ramps up the rpms to burn off the soot on a screen - low rpms will actually create a bit more of the soot.
You do not have this feature - which is a good thing btw.

Here is a long but very interesting read on the mechanics behind diesels and how slobbering is created and somewhat prevented.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a151273.pdf

Despite this - there is a simple solution!!!! Got to the local big box store in the plumbing department.....get you a P-trap made of metal...... cut and clamp over the tip of the exhaust!!! Simply redirect the soot!!!

View attachment 52822

The report that you referenced is concerning diesel engines in military gensets. I have seen this report when I wass in the Army, long ago. The diesel engines of today do not exhibit the slobbering problem except in very rare case where a high number of hours and subsequent excessive wear has occurred. There has also been some reports in engines that have been performance chipped. The engines in modern Kubota's do not have this problem with normal usage.

BTW, in case you are wondering why military engines had this problem, it is because they were made to a different specification so that they could burn fuel sourced from all over the world. Also, this report only dealt with military TACTICAL engines.

 

[lugbolt]

multifuel

a good reason the detroit 2 strokes stuck around for so long, they'd run on basically anything you put in the gas tank except pee and water and sometimes gasoline

similarly, everyone thinks that mil spec is top notch but it's not. Military takes bids on everything so they get the cheapest garbage that will do the job acceptably to THEIR standards

non dpf engines will emit some soot it's normal that's what dpf is (diesel particulate filter, aka soot filter)

 

[SidecarFlip]

multifuel

a good reason the detroit 2 strokes stuck around for so long, they'd run on basically anything you put in the FUEL tank except pee and water and sometimes gasoline

similarly, everyone thinks that mil spec is top notch but it's not. Military takes bids on everything so they get the cheapest garbage that will do the job acceptably to THEIR standards

non dpf engines will emit some soot it's normal that's what dpf is (diesel particulate filter, aka soot filter)

Fixed it for ya....

Right on about Mil-Spec stuff. Everything the military buys is on competitive bid. No oxidation catalyst or DPF on ANY of my diesels. Pizz on that junk.

 

[armylifer]

Fixed it for ya....

Right on about Mil-Spec stuff. Everything the military buys is on competitive bid. No oxidation catalyst or DPF on ANY of my diesels. Pizz on that junk.

The message I was trying to convey is not that military equipment is junk, that is just not so. In the case of military diesel engines in equipment made during the timeframe of that report, 1980's, fuel sources in the areas of tactical interest or conflict were often sub-par. The engines were purposely spec'd to be able to operate on that often sub-par fuel if our own stocks became unavailable. Believe me, I have used that equipment and I staked my life on it then as I would now. Our military is supplied with the finest equipment available, for its intended purposes. The only problem is that our needs change faster than the civilian pukes can supply us with what we need. They send us out to do a job and then shackle us through the procurement process.

 

[SidecarFlip]

I'm intimately familiar with the military procurement end. My wife retired a GS 13 Step 10 from the DOD Logistics and Procurement division.. She bought what you used. Maybe I should say familiar instead. Lots of stuff she handled was classified and I didn't ask. Was a need to know and I didn't need to know.

Military still uses exclusively Detroit Diesel engines for land based motive power and power generation except in tanks. Just not 2 stroke Detroit's now but DDEC inline 4 strokes sans ALL emissions hardware.

You won't find DPF or oxidation catalyst (DEF) on any military engine even today. All that is for consumers to agonize over. Military is 100% exempt from it.

 

[armylifer]

I'm intimately familiar with the military procurement end. My wife retired a GS 13 Step 10 from the DOD Logistics and Procurement division.. She bought what you used. Maybe I should say familiar instead. Lots of stuff she handled was classified and I didn't ask. Was a need to know and I didn't need to know.

Military still uses exclusively Detroit Diesel engines for land based motive power and power generation except in tanks. Just not 2 stroke Detroit's now but DDEC inline 4 strokes sans ALL emissions hardware.

You won't find DPF or oxidation catalyst (DEF) on any military engine even today. All that is for consumers to agonize over. Military is 100% exempt from it.

What you say about emissions not being on military engines is absoutely true. The military needs reliability and they realize that emissions equipment is just not reliable.

 

[SidecarFlip]

So does Kubota tractor owners (and all the others as well).....

Just before I retired from Freightliner, we got a huge shipment of OshKosh Military 6 x 6's in for pre operation deployment checkout. They were all DDEC 60's, no emissions hardware with Allison transmissions. Nice trucks all painted desert camo.

 

[MSG H]

Military wheeled vehicles haven’t seen Detroit engines in a decade. All wheeled vehicles larger than a HMMWV use CAT engines, C15-C7.

 

[armylifer]

So does Kubota tractor owners (and all the others as well).....

Just before I retired from Freightliner, we got a huge shipment of OshKosh Military 6 x 6's in for pre operation deployment checkout. They were all DDEC 60's, no emissions hardware with Allison transmissions. Nice trucks all painted desert camo.

I heard that when these non emission vehicles come on the surplus market that they are retrofitted with emissions junk, any truth to that?

 

[armylifer]

Military wheeled vehicles haven’t seen Detroit engines in a decade. All wheeled vehicles larger than a HMMWV use CAT engines, C15-C7.

I don't know. I retired 25 years ago. I have two children serving though.

 

[MSG H]

Oshkosh, Stewart Stevenson and BAE all. Caterpillar has the contracts now.

 

[MSG H]

I heard that when these non emission vehicles come on the surplus market that they are retrofitted with emissions junk, any truth to that?

No, they are auctioned as is. Vehicles can be looked at online and at the auction house. Part availability is going to be the problem. Cat engine, Allison transm but the rest?

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