Exhaust Smell

[Just Plain Jeff]

Hang in there with me on this one.

It's my contention that the smell of the exhaust of a diesel engine is one way to determine how well the engine is running.

Here are some observations: Our 8V92 had the sweetest smelling exhaust; it seemed as if it ran like a Swiss watch. On startup, even if you had no other senses, you could identify the exhaust smell as an 8V92. The Series 60 also has a distinctive odor.

Now a few days ago, I was over at an RV dealership where there were a bunch of other coaches, mostly plastic. These were CAT and Cummins-powered coaches and the exhaust smell was distinctively different; indeed it smelled, 'raw,' suggesting that those engines were not as efficiently combusting the fuel. There was no apparent smoke coming from these mostly new coaches, but the particulate seemed to be less combusted, if that makes any sense.

So, for those of us who live for 'diesel smoke in the morning,' an 8V92 or a Series 60, as the nose goes, seem to do a much better job. What doesn't make sense in all of this however, is that my truck, which has a Cummins, smells more like the Detroits than the motorhomes. It does have the Hitman's custom 5-inch exhaust system on it, if that makes any sense.

All this makes me wonder about EGR standards and particulate emissions. If not all engines emit the same quantity of particulate/gallon, for example, creating standards for all diesel engines seems to be somewhat of an exercise in bureacracy (if particulate smell is an indicator). In statistics, that's called an Alpha error: Making an observation on a single case which applies to all members of a group.

What say y'all?

[JIM CHALOUPKA]

Hang in there with me on this one.

It's my contention that the smell of the exhaust of a diesel engine is one way to determine how well the engine is running.

Here are some observations: Our 8V92 had the sweetest smelling exhaust; it seemed as if it ran like a Swiss watch. On startup, even if you had no other senses, you could identify the exhaust smell as an 8V92. The Series 60 also has a distinctive odor.

Now a few days ago, I was over at an RV dealership where there were a bunch of other coaches, mostly plastic. These were CAT and Cummins-powered coaches and the exhaust smell was distinctively different; indeed it smelled, 'raw,' suggesting that those engines were not as efficiently combusting the fuel. There was no apparent smoke coming from these mostly new coaches, but the particulate seemed to be less combusted, if that makes any sense.

So, for those of us who live for 'diesel smoke in the morning,' an 8V92 or a Series 60, as the nose goes, seem to do a much better job. What doesn't make sense in all of this however, is that my truck, which has a Cummins, smells more like the Detroits than the motorhomes. It does have the Hitman's custom 5-inch exhaust system on it, if that makes any sense.

All this makes me wonder about EGR standards and particulate emissions. If not all engines emit the same quantity of particulate/gallon, for example, creating standards for all diesel engines seems to be somewhat of an exercise in bureacracy (if particulate smell is an indicator). In statistics, that's called an Alpha error: Making an observation on a single case which applies to all members of a group.

What say y'all?
Well I like the smell of my Chevy over your Cummins! It sounds better too! JJC :p

[Petervs]

Now you are just blowin' smoke!

Give me a break already, the smell you are used to smells the best, and the chemical formulation of some other guy's diesel is going to be a little different just because he bought it in a different place and crude oil from some other hole in the ground was used to make it.

It is just like drinking water. The water at your house, or the bottled water you buy at home always tastes the best because that is what your taste buds are calibrated to. Go somewhere else and you drink water it always tastes bad.

Stop breathing exhaust fumes, it is killing brain cells, and get back to work polishing the stainless!

Peter vS
94 Marathon XLV

[Joe Cannarozzi]

I say-I hope you make sure no one is looking before you go around sniffing tail pipes.

I say-What it makes you feel in the seat of the pants is a better indicator than what your smelling at the tail pipe.

x-power from x-mpg This is the question. The guy behind me can deal with the tail pipe.

[Jon Wehrenberg]

OK, I'll add to this insanity.

I don't have a nose as sensitive as JPJ, but on a backhoe I used to own the exhaust upon start up was completely different than the exhaust when it was warmed up.

I think JPJ ought to quantify these smells and make a chart.

[JIM CHALOUPKA]

OK, I'll add to this insanity.

I don't have a nose as sensitive as JPJ, but on a backhoe I used to own the exhaust upon start up was completely different than the exhaust when it was warmed up.

I think JPJ ought to quantify these smells and make a chart.

If "BEAUTY IS IN THE EYE OF THE BEHOLDER" then ODOR MUST BE IN THE NOSE OF THE SMELLER ?

Which reminds me guys order your St Valentine's Day roses. They're worth it.:p

JIM

[Jon Wehrenberg]

"Which reminds me guys order your St Valentine's Day roses. They're worth it."

What a suck up! Save your money for diesel fuel and LEDs.

[Just Plain Jeff]

By Jon: I think JPJ ought to quantify these smells and make a chart.

Actually that's not a bad idea. It would be a Chi square, comparative, but not predictive.

on a backhoe I used to own the exhaust upon start up was completely different than the exhaust when it was warmed up

The road to Truth begins with a single believer. i sense the beginning of a movement here.

[Jon Wehrenberg]

I'm behind you on this one, Camper Boy.

[Jerry Winchester]

What will Camper Boy smell when he starts burning Bio Willie or grease oil in the coach?

And to further Jon's backhoe analogy, after traveling 1400 miles with Mike, tacos smell pretty good when you start up, but don't smell as sweet after the engine warms up :eek:

Then he asks me (as we drive along 15 miles of continuous dairy farms south of Las Cruces), "Dude, is that you?" That's what happens when you travel in the country with a city boy.

[JIM CHALOUPKA]

"Which reminds me guys order your St Valentine's Day roses. They're worth it."

What a suck up! Save your money for diesel fuel and LEDs.

Jon! What color are you ordering? :D :D :D JIM

[lewpopp]

Just my 2 cents. The smell of your 8v92 comes strictly from memory, my boy. It's been nearly a year and a half since you owned the 8v92. Am I close? Since then they changed the formula of the diesel fuel and removed most (if not all) of the sulfer. At Parliament at one of the seminars we were told that the new formula has been in the pipeline for a long time. If you find any of the old formula it would be a lucky find.

Yeah, I know JDUB has a large hole full of the old lower priced sulfer + fuel, but he will hang on to it as long as he can.

How far off base am I comparing the smell of the old fuel to the new?

The funny thing at Parliament and TGO was to watch JPJ go around, put one finger to his nose to close a nostril, and take a deep breath to get a super smell of the fumes. Be careful chasing some of these coaches a foot, they may stop quicker than you expect. The tow cars could possibly pick you off. Maybe that's where the dent came from on the Saturn.

Lew

Lew

[Just Plain Jeff]

Lew:

I think you may have hit the nail on the head here.

If it turns out that different engines, CAT, Cummins and Detroit all handle the new fuel differently, then there are going to be quite different operating characteristics of each engine over their life.

You are right, it has been some time since I was around a running 8V92, but I can tell you that the new coaches I was around with the Cummins and the CATs smelled as if the particulate was chewed up, not compressed and burned.

It is also very likely that these engines were designed far before any significant testing was taking place with the newer fuels...albeit they should have been, but that's another matter...

In a diesel engine, you need compression power and a degree of lubrication from the fuel to ensure a long life for the mill. If the newer fuels are not providing same, then there will be a host of issues for these new coaches buyers down the road, as the engine life of the coach will wind up possibly being significantly different than what was expected and will require different preventative maintenance programs than what the manufacturers would have originally recommended.

In addition to slight loss of fuel economy, following the logic from your keen observation, the lubricity of fuel will affect wear and tear on the inside of the engine.

So my original observation didn't stink.

It may be that different engines handle different fuels quite indivdually. As to the S60 we currently have, it doesn't seem to be any different than the older fuels, but that many not be the case with other less-tolerant engines.

We're on to some good stuff now. Thanks for your insight.

[MangoMike]

Sure, sure....


Blame it on the cows... right.


Since when do dairy cows eat Tacos?


mm

[Jon Wehrenberg]

It is an old wives tale about relying on fuel for lubrication.

Any fuel.

We use oil for lubrication, and any anti wear characteristics that fuel may possess from additives is so slight as to be happenstance.

[garyde]

I can definately smell Jdub....Oh, is that the topic? Lets have a blind fold test at POGIII. We'll blindfold Jon and start all th diesels! Then we'll spin him around ...... whops, sorry, what were you guys saying?

[Just Plain Jeff]

As Lew pointed out, the 'lubricity' issue is a big deal. A Google search revealed 186,000 hits on the point: http://www.exxon.com/USA-English/GFM/Products_Services/Fuels/Diesel_Fuels_FAQ.asp ("http://www.exxon.com/USA-English/GFM/Products_Services/Fuels/Diesel_Fuels_FAQ.asp")

The use of new fuels will increase the PM on existing engines.

Read and weep.

[Jon Wehrenberg]

The place to look for information on lubricity is in the standards which apply to fuels, not a self serving web site owned by a refiner of fuels and oils.

The engine uses fuel for combustion, not for lubrication.

I would be more worried about fuels that contain components that are incompatible with seals, hoses, and other materials in the fuel storage and delivery systems in our coaches.

[bill&jody]

did you read the DD document i posted here ("http://wheresJodyAndBill.com/pdfs/DD-LubeFuelFilter.pdf")?

Diesel fuel sulfur content above 0.3% mass causes premature ring and cylinder
wear and deposit formation.
it sez the longevity of DD engines is reduced if higher sulphur fuel is used. lower sulphur means less sulphuric acid, less corrosion, less wear. maybe your experience would indicate otherwise, tho.

where does this info come from that sez low sulphur diesel implies more wear?

wmm

[Joe Cannarozzi]

Bill looks like your right, rest assured, horror stories comming from the uninformed. Still, I'm thinkin if the content was .05 before, and tollerance is .3 thats already way low. Really didn't need it.
What is it now, ultra low, .02, zip?
Even if 0, thats a pretty slite change anyway?

If fuel milage suffers, IT STINKS, no pun intended.

Oh, I forgot, its all for cleaner air, shame on me.

[Just Plain Jeff]

Don't have all the facts yet, but it turns out some clowns in our Federal EPA had mandated that diesel engines have catalytic converters. All diesel engines. So, a bunch of generator engines have them. Thing is, they don't get hot enough for the catalytic converters to work, so they eventually just clog up and then the ol' gennie won't run.

These geniuses apparently thought that diesel engines were more polluting than gas engines, but didn't do their homework.

Some converters have removed them, some haven't.

Gonna try to dig into this one a bit more and report back. Anyone else run across this deal?

Thanks.

[Orren Zook]

OTR trucks have had something similar to what you describe for a few years, the cost for that muffler runs in the $1200 range. Similar mufflers (same decible rating and size) without the 'deluxe polution equipment' runs $55-65 here in Ohio -and- you can detect a change in the scent of the exhaust between the two. I would think that areas having mandatory Echeck of the exhaust would enforce replacement of like for like items on the exhaust to comply with local emission requirements. Maybe Prevost has a similar exhaust setup on their late model (98 and newer) coaches to make them 50 state compliant on emissions, or perhaps their limited production would allow an exemption.