Is fuel quality an issue in engine failures?

Glend · **Posted:** Tue Jan 15, 2013 6:49 pm

While trying to find any examples of VM engine failures in Australia, I was reminded by one owner over here that Mercedes Benz had a similiar engine issue with the 300 series diesel in the USA, which became known as a "Rod Bender" in the US market but had no problems within it's Euro zone origins.

There seems to be some school of thought that the MB engine problems were due to differences in fuel quality standards at the time. Could this be the case with the VM engine as well?

Quote:

The current standard for diesel sold in European Union, Iceland, Norway and Switzerland is set in EN 590, with a minimum cetane index of 46 and a maximum cetane number of 51. Premium diesel fuel can have a cetane number as high as 60.

In North America, most states adopt ASTM D975 as their diesel fuel standard and the minimum cetane number is set at 40, with typical values in the 42-45 range.

Here is the source for that information:

http://en.wikipedia.org/wiki/Cetane_number

It is my understanding that most Euro diesel today is around 50 cetane.

Since the VM is a Euro zone engine, it makes sense that it was engineered to run on the EN590 standard fuel.

"Many manufacturers recommend using an EN590 specification fuel as that is what modern engines have been designed to run best on." Source: https://www.nfuonline.com/Our-work/Regu ... our-tank-/

Australia also complies with the Euro standard, with a minimum of 46 but most fuels seem to be towards the upper end of the range. In recent years Premium diesel has become more popular and the price differences are disappearing with volume increases in Premium use. I use, and have used a premium diesel for the last few years.
Sulfur levels are mandated as less than 10ppm which I believe also apply in the USA.

Source data:

http://www.environment.gov.au/atmospher ... iesel.html

Does the difference of cetane number standards make any difference in engine performance or longevity?

I found this site that claims that there is:

"..... if an engine is operated with a fuel that features a cetane number lower than the recommended amount, there can be several drawbacks. The vehicle will not operate as smoothly, and the poor operation can result in vibrations as well as extra noises. Additionally, it could create a larger amount of emissions and wear on the engine. In some cases, the driver may even have difficulty starting the engine."

Source: http://www.chipexpress.com/articles/rat ... e-numbers/

Is this a factor, or just unrelated noise clouding the issue?

ATXKJ · **Posted:** Tue Jan 15, 2013 8:37 pm

I would doubt that it is the root problem

however if you have 4-5 things that are marginal to begin with - it might push it over the edge.

(I've heard the Cetane in the US was because the big trucks didn't want to pay the extra for good Diesel)

AZ CRD · **Posted:** Fri Jan 18, 2013 9:51 am

Another reason to feed my tractor a good percentage of home brewed biodiesel . . .

kjjet · **Posted:** Fri Jan 18, 2013 11:56 am

I dont beleve a lower Cetane is real bad for your engine, your just not going to get the fuel mileage you could if the Cetane was higher.

I beleve lubrication or lack of lubrication using (ULSD) Ultra Low Sulfur Diesel is worse for your engine. Injectors, fuel pumps and valvetran all suffer by using it. But... we here have no choice, so a good additive that adds lubricity is needed. Some also increase Cetane. I currently add LUBRIBOR to each fueling. It is specially formulated for ULSD and Jet fuel. You will notice the differance the first time you use it!

It is not sold in general stores so:

Google LubriBor By Hammonds

dkenny · **Posted:** Fri Jan 18, 2013 6:53 pm

kjjet,
at first I was going to disagree with you, but I don't..why..
my wife uses biodiesel..when we have to available..ie I can make enough..
blah..blah...I know..so what..well biodiesel is the best lubricate additave for diesel fuel..
2cycle oil come is 2nd..but anything added that improves lubricity of the fuel helps..

I know my 99 cummins is quieter on biodiesel and noiser on higher blends of diesel(less biodiesel).
I don't drive my wife jeep enough to notice a change in fuels by sound

but why did we loose a CP3 at 50Kmiles? might have been just the fuel regulator on the back of the CP3?

so could this be an issue..I think so..why
low cetane number are like low octane numbers...sure there's difference between the two...but from what I understand..low cetance number fuels ignites sooner(not good)..like higher octance resists knocking..biodiesel is high cetane fuel..if I recall 50+

-just my 2 cents

-dkenny

Glend · **Posted:** Fri Jan 18, 2013 7:01 pm

ULSD usually has a lubricant added to protect pumps seals etc in place of the role sulfur used to provide - well at least down here that is mandated in the fuel standards.

dkenny · **Posted:** Fri Jan 18, 2013 7:28 pm

Glend,
they have the same requirement..here...
but why the change in sound in my truck..biodiesel its quieter..if I add 2 cycle oil its quieter..hum

do they add enough lubricity? or just enough to met a min spec that's too low?
add a quart of 2 cycle oil to you jeep and see if you notice a difference

-dkenny

kjjet · **Posted:** Fri Jan 18, 2013 8:02 pm

I'm not saying low Cetane is not bad, just not as bad as lack of lubrication is for your engine.

kjjet · **Posted:** Fri Jan 18, 2013 8:14 pm

Just what i found online: Not my words but i beleve:

HOW DOES THE OCTANE OF DIESEL AND/OR JET FUEL COMPARE TO GASOLINE?
Diesel and Jet fuel (along with kerosene) have, indeed, terrible octane numbers; typically about 15-25 "octane". They tend to ignite easily from high compression. Their use in a gasoline engine will quickly destroy the engine.
Diesel fuel is rated by its cetane number which is determined, like octane, by running the fuel in a test engine. Instead of heptane and iso-octane they use napthalene (cetane rating = 0) and n-cetane (cetane rating = 100). In total opposite to octane ratings, the higher the cetane rating the higher the fuel's propensity to knock!
Just as using a fuel with an octane number higher than necessary in a gas engine will gain you noting, using a fuel with a cetane number higher than necessary in a diesel engine gets you nothing. On the other hand, where using a fuel with too low an octane number in a gas engine will result in a damaged engine, using a fuel with too low a cetane number of a diesel engine will just result in a rough-running (or not running at all) engine with no damage.

dkenny · **Posted:** Fri Jan 18, 2013 9:02 pm

I have a problem with this
Diesel and Jet fuel (along with kerosene) have, indeed, terrible octane numbers; typically about 15-25 "octane". They tend to ignite easily from high compression. Their use in a gasoline engine will quickly destroy the engine.
..because its not the case..espically the last sentance..

dump a gallon of diesel in gas car..it'll smoke or not even run..but damage..none..
dump a gallon of gas in you diesel..and if you have enough diesel you might get off without damage..too much gas...and byebye diesel...

sorry gas has a lower flash point than diesel..which means it'll ignite at a lower temp..than diesel..bad news in a diesel(compression engine)..

dump a gallon of 2 cycle oil in a gasser..does it destroy it..no..
dump a gallon of gas in a diesel..same question..it might destroy it
-dkenny

kjjet · **Posted:** Sat Jan 19, 2013 12:16 pm

Ignite from spark and Ignite easily from high compression is two different things.

dkenny · **Posted:** Sat Jan 19, 2013 3:39 pm

yes...but not this
"Their use in a gasoline engine will quickly destroy the engine" -> I don't agree!

but gas engines aren't high compression.. diesel engines are..outside of race car engines most are under 12:1 compression..diesels are generally over 17:1 without boost

and putting diesel/kerosene in gas engines will not damage the engine..it might not run..but not running is not damage..

put gasoline in a diesel..that's a different story..

in general the quote is correct, but some parts are just wrong.

<qoute>
Ignite from spark and Ignite easily from high compression is two different things.</qoute>

yes..it is
diesel doesn't ignite from spark easily..kerosene/fuel oil sprayed will..
gasoline..easy from spark..in liquid form
biodiesel..only if sprayed on a fame..spark it might.

I think the lubrication in the fuel might be a bigger issue..

-dkenny

kjjet · **Posted:** Sat Jan 19, 2013 5:30 pm

dkenny wrote:

I think the lubrication in the fuel might be a bigger issue..

-dkenny

I agree!

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Cetane is a measure of the ignition delay. 40 cetane may have 150 ms of delay after injecting before the burn starts, whereas a 50 cetane fuel would have about 100 ms of delay. Higher cetane fuel has less ignition delay and it tends to have a little more complete burn. To take full advantage of higher cetane fuel one would want slightly modified injection timing vs. stock.

Glend · **Posted:** Sun Jan 20, 2013 4:02 am

GreenDieselEngineering wrote:

Cetane is a measure of the ignition delay. 40 cetane may have 150 ms of delay after injecting before the burn starts, whereas a 50 cetane fuel would have about 100 ms of delay. Higher cetane fuel has less ignition delay and it tends to have a little more complete burn. To take full advantage of higher cetane fuel one would want slightly modified injection timing vs. stock.

So when you say it "...tends to have a little more complete burn." Does that mean it burns cleaner, or produces less soot?

AZ CRD · **Posted:** Sun Jan 20, 2013 10:11 am

GreenDieselEngineering wrote:

Cetane is a measure of the ignition delay. 40 cetane may have 150 ms of delay after injecting before the burn starts, whereas a 50 cetane fuel would have about 100 ms of delay. Higher cetane fuel has less ignition delay and it tends to have a little more complete burn. To take full advantage of higher cetane fuel one would want slightly modified injection timing vs. stock.

Pardon my ignorance, but is engine timing a variable you can control in your tunes? If so, I might want to look into a custom biodiesel tune. I'm currently running InMotion stage II with SEGR.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

AZ CRD wrote:

GreenDieselEngineering wrote:

Cetane is a measure of the ignition delay. 40 cetane may have 150 ms of delay after injecting before the burn starts, whereas a 50 cetane fuel would have about 100 ms of delay. Higher cetane fuel has less ignition delay and it tends to have a little more complete burn. To take full advantage of higher cetane fuel one would want slightly modified injection timing vs. stock.

Pardon my ignorance, but is engine timing a variable you can control in your tunes? If so, I might want to look into a custom biodiesel tune. I'm currently running InMotion stage II with SEGR.

Certainly we change the injection timing. We have many customers running various forms of bio fuel and all have been obtaining very good results. How is your FE with your current setup?

AZ CRD · **Posted:** Mon Jan 21, 2013 9:19 am

GreenDieselEngineering wrote:

AZ CRD wrote:

GreenDieselEngineering wrote:

Cetane is a measure of the ignition delay. 40 cetane may have 150 ms of delay after injecting before the burn starts, whereas a 50 cetane fuel would have about 100 ms of delay. Higher cetane fuel has less ignition delay and it tends to have a little more complete burn. To take full advantage of higher cetane fuel one would want slightly modified injection timing vs. stock.

Pardon my ignorance, but is engine timing a variable you can control in your tunes? If so, I might want to look into a custom biodiesel tune. I'm currently running InMotion stage II with SEGR.

Certainly we change the injection timing. We have many customers running various forms of bio fuel and all have been obtaining very good results. How is your FE with your current setup?

Yeah. Last time I adjusted engine timing was on a '67 Mercury Cougar using a timing light and rotating the distributor. Havn't a clue how a diesel is timed.

My FE is not great. I run B50 in the winter and B75 in the summer. Get about 19mpg city & 25mpg at 75mph on flat hgwy. The bio has, of course, fewer btu's per gallon. And, the Michelin load E's are relatively heavy.

Don't want to lose much torque. It comes in handy, offroad especially.

I'll drop you an email so we don't hijack the thread any more than I already have. Thanks!

Is fuel quality an issue in engine failures?

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