Ultra Low Sulfur Diesel - Anything to worry about????

Some interesting facts about the qualities and problems of Ultra Low Sulfur Diesel.

*
<h5>Lubricity</h5>
The most immediate concern with ULSD certainly the one that has received the most publicity is lubricity. When diesel fuel is refined to make ULSD, it is reacted with hydrogen to remove the sulfur. This process also removes much of the fuels lubricity. (Many people mistakenly believe that it is only the sulfur that supplies lubricity.) Lubricity is essential in diesel fuel to reduce friction at finely machined pumps and injectors; without sufficient lubricity, a diesel would grind itself to a premature death.

Minimum lubricity is a requirement of the ASTM-D975 standard, which means oil companies must use either soy biodiesel or a synthetic additive to return fuel to its pre-ULSD lubricity levels. Soy biodiesel has the potential to loosen built-up gunk in the tank and clog filters, but not to the extent that ethanol did with gasoline tanks. Note, however, that a synthetic additive is more likely to be used, since it is less expensive and more stable than soy.

*Cetane

Diesels rely on compression (and not a spark) to ignite the fuel. A higher cetane number means the fuel will ignite more readily, run smoother and produce less smoke. All diesel fuel must have a cetane rating of at least 40. Most regular diesel fuel has a cetane rating of 43 to 45, which should be fine for most boat engines. The good news is that the cetane numbers remained the same with ULSD.

Using an additive to boost cetane may help your engine, but be aware that an independent study of 19 additives sold to improve an engines cetane rating found that five had no significant effect on the fuels cetane rating and four additives significantly lowered the cetane content.

*Corrosion

Since ULSD was introduced in 2006, some suppliers have reported accelerated corrosion in underground steel storage tanks. The cause is unclear and no one is certain whether it is related to ULSD, an additive, or something that occurred during the transition from low sulfur diesel (LSD) to ULSD. (Curiously, in Europe, where ULSD has been in use for much longer, there have not been any corrosion issues, according to a report in Fuel Oil News.) The only solution, thus far, is to keep tanks as clean as possible with no water bottoms so there is nothing for the fuel to react with. On boats, repairers we talked with had not seen any indications of corrosion problems.

*Leaking Gaskets

When the transition was made to LSD in 1993, there were problems with leaking gaskets. Newer gaskets that resist leaking were developed, but there were some fears that the gaskets might not stand up to ULSD. After talking to numerous marina owners and engine manufacturers, leaking gaskets dont appear to be a problem.

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<h5>Water and Bugs</h5>
Microbial growth bugs needs water to grow and has always been a concern with diesel fuel. ULSD holds less water than older, higher-sulfur fuels. While that sounds like good news, its not; any water that finds its way into a boats tank is less likely to be absorbed into the fuel and is more likely to wind up at the bottom of the tank, where it can help spawn the dreaded microbial bugs. Biocides kill bugs (as will freezing temperatures), but their tiny little carcasses accumulate at the bottom of the tank and form a funereal goo. Its possible that tanks may need to be cleaned more often to prevent filter clogging and corrosion.

The best defense is to keep water out of your fuel by keeping the tank topped off to reduce condensation, only buying fuel from a reliable source, and checking your water separator. If water starts to appear routinely, youll have to take steps to clean your tank and polish the fuel.

Cold Weather

The refining process used to lower the sulfur content of ULSD also can affect the content of naturally occurring paraffin (wax) in diesel fuel, which causes it to gel more readily in cold weather. For the vast majority of boat owners, who lay up their boats over the winter, cold weather starting isnt a concern. For anyone who plans to use their diesel in winter, distributors compensate for colder temperatures by selling a winter blend. If you still have a summer blend in the tank, youll need to use a coldweather additive and follow the instructions. Use only the recommended dose, as too much additive may make gel problems worse.

*fuel Source

A reliable source for your fuel is (and has always been) very important. A high-volume dealer is far more likely to have fresh fuel than a sleepy, backwater marina. As a general rule, diesel fuel can be expected to remain healthy for at least a year. The major oil companies or distributors will sometimes use their own additives (antioxidants and biocides). If the fuel has been treated and stored in a clean (no rust), water-free tank that is in a cool (or underground) climate, diesel fuel can last as long as three years

An excerpt from Seaworthy Magazine


-- Edited by Edelweiss on Saturday 8th of October 2011 01:09:07 AM

The end of the pipeline mixer is supposed to add the proper lubricity additives , but you are betting your injection system on him.

The older the engine the more it will miss the Sulfur.

Some folks will add a gallon of cheap 2 outboard stroke oil, others will use a gallon of ATF (to 100 of diesel) .

In the archives should be a lubricity study from a couple of years ago.

Worth a look as many "cures" are harmfull!


-- Edited by FF on Saturday 8th of October 2011 04:15:35 AM

Ultra Low Sulfur diesel with refiner additives has been*used in Europe for many years with VW, Volvo, Mercedes etc. seeminly doing just fine. Much of the concern in the US is raised by the golden elixir companies trying to boost sales*by running down Chevron, Shell, BP etc. refining capability.

Me, I spend about $20 at the end of summer by adding Startron, more for the sitting fuel than the perceived lack of lubricity. I have yet to see a controlled study where ATF or outboard oil is of any benefit, probably because it is too cheap and doesn't enrich the additive suppliers.

I have been in the middle fo the move to lower sulfur fuels for over a decade both in the US and in other countries. Provided the newer diesel fuels meet Cat, Cummins or MTU specs they do not require additives at the job location. It would be highly unusual for major brand diesel to not meet spec -*if off spec it is caught*by the refiner and reformulated. Plus the Euro and NA enviro agencies are in the middle of insuring spec is maintained to keep our air clean.

*

*

Tom, you think Startron is best? *I've never used anything, but perhaps I should. *When we did Delfin's refit, she had around 1200 gallons on her that sat for 3 years. *When relaunched it seemed to burn just fine, although I thought might have produced a bit more visible exhaust.

sunchaser wrote:
Ultra Low Sulfur diesel with refiner additives has been*used in Europe for many years with VW, Volvo, Mercedes etc. seeminly doing just fine. Much of the concern in the US is raised by the golden elixir companies trying to boost sales*by running down Chevron, Shell, BP etc. refining capability.

Me, I spend about $20 at the end of summer by adding Startron, more for the sitting fuel than the perceived lack of lubricity. I have yet to see a controlled study where ATF or outboard oil is of any benefit, probably because it is too cheap and doesn't enrich the additive suppliers.

I have been in the middle fo the move to lower sulfur fuels for over a decade both in the US and in other countries. Provided the newer diesel fuels meet Cat, Cummins or MTU specs they do not require additives at the job location. It would be highly unusual for major brand diesel to not meet spec -*if off spec it is caught*by the refiner and reformulated. Plus the Euro and NA enviro agencies are in the middle of insuring spec is maintained to keep our air clean.*

Click to expand...

I would say the article pretty much tends to agree with you.* I have never added anything to my diesel in 35 years of operation. (Other than the gallon of gasoline we accidentally pumped in right after we got the boat. )* **However the comment regarding the possibility of more water accumulation in your tanks with ULSD may add some credence to the argument for polishing your fuel??
I worked for Union Oil right out of college, many years ago, and the product delivered to the retailer was very reliable, grade consistent and clean even then. When there were problems, 95% of the time we would find it was at the retail end, stations with leaky tanks, water in tanks, fill caps not closed properly or seals leaking, and of course the occasional knucklehead who would buy gray market gas and dump it in his tanks (One can only guess how old that gas was or where it came from?)*

With modern day EPA requirements for tanks and inspections the leaky tanks have pretty much disappeared and I would tend to believe we are down to human error and knuckleheads now.**

Larry B


-- Edited by Edelweiss on Saturday 8th of October 2011 10:38:43 AM

Carl* -* Of the various additives out there 4 years ago, I selected Startron, primarily for its biocide claims. Others may be equal or better with Valvetec leading the PR blitz parade. Steve D'Antonio's recent PMM series was pretty weak on recommendations given the advertising $$ PMM garners from a half dozen or so additive suppliers.

I was in the lead mining business 35 years ago when TEL disappeared from gasoline with lead prices plummeting as a result. We survived that (non) issue but now methanol is raising a host of real concerns with little government sympathy. Unless (very) ULSD shows a problem akin to melting tanks and disintegrating rubber pieces ala methanol, we are all going to be subjected to lots of gray area advertising BS and old wives tales.

Thanks for the article Larry, it has appeared in several boating mags recently and seems factual and*balanced from my viewpoint. IMHO, water in fuel should be less a polishing discussion and more a "find the sources" hunt.

"The following are the preliminary results of a research study on diesel fuel Lubricity Additives. There is likely to be further commentary and explanation added at a future time.

PURPOSE:

The purpose of this research was to determine the ability of multiple diesel fuel additives to replace the vital lubricity component in ULSD (Ultra Low Sulfer Diesel) fuel.

HISTORY:

ULSD fuel is the fuel currently mandated for use in all on road diesel engines. This fuel burns cleaner and is less polluting than its predecessor, called Low Sulfer Diesel Fuel. Low sulfer fuel contained less than 500 ppm of sulfer. ULSD contains 15 ppm or less.
As diesel fuel is further refined to remove the polluting sulfer, it is inadvertently stripped of its lubricating properties. This vital lubrication is a necessary component of the diesel fuel as it prevents wear in the fuel delivery system. Specifically, it lubricates pumps, high pressure pumps and injectors. Traditional Low sulfer diesel fuel typically contained enough lubricating ability to suffice the needs of these vital components. ULSD fuel, on the other hand, is considered to be very dry and incapable of lubricating vital fuel delivery components. As a result, these components are at risk of premature and even catastrophic failure when ULSD fuel is introduced to the system. As a result, all oil companies producing ULSD fuel must replace the lost lubricity with additives. All ULSD fuel purchased at retail fuel stations SHOULD be adequately treated with additives to replace this lost lubricity. The potential result of using inadequately treated fuel, as indicated above, can be catastrophic. There have been many documented cases of randomly tested samples of diesel fuel. These tests prove that often times the fuel we purchase is not adequately treated and may therefore contribute to accelerated wear of our fuel delivery systems. For this reason it may be prudent to use an after market diesel fuel additive to ENSURE adequate lubrication of the fuel delivery system. Additionally, many additives can offer added benefits such as cetane improver, and water separators or emulsifiers.

CONTENT:

In this study we will test multiple diesel fuel additives designed to replace lost lubricity. The primary component of this study is a side-by-side laboratory analysis of each additives ability to replace this vital lubricity. Additionally, claims of improving cetane, water separation or emulsification, bio-diesel compatibility and alcohol content will be noted. These notes were derived from information that was readily available to consumers (via the label and internet information) and none of this information has been evaluated for validity and/or performance. Cetane information has only been noted if the word cetane was used in the advertising information. The words improves power has not been translated to mean improves cetane in this evaluation. Information on alcohol content is provided by indicating contains no alcohol. Omission of the words contains no alcohol does not imply that it does contain alcohol. This information was simply missing in the information available to a consumer. However, the possibility of a form of alcohol in these products is possible. Additionally, information on dosages and cost per tankful are included for comparison purposes.

How Diesel Fuel Is Evaluated For Lubricating Ability:

Diesel fuel and other fluids are tested for lubricating ability using a device called a High Frequency Reciprocating Rig or HFRR. The HFRR is currently the Internationally accepted, standardized method to evaluate fluids for lubricating ability. It uses a ball bearing that reciprocates or moves back and forth on a metal surface at a very high frequency for a duration of 90 minutes. The machine does this while the ball bearing and metal surface are immersed in the test fluid (in this case, treated diesel fuel). At the end of the test the ball bearing is examined under a microscope and the wear scar on the ball bearing is measured in microns. The larger the wear scar, the poorer the lubricating ability of the fluid. Southwest Research runs every sample twice and averages the size of the wear scar.
The U.S. standard for diesel fuel says a commercially available diesel fuel should produce a wear scar of no greater than 520 microns. The Engine Manufacturers Association had requested a standard of a wear scar no greater than 460 microns, typical of the pre-ULSD fuels. Most experts agree that a 520 micron standard is adequate, but also that the lower the wear scar the better.

METHOD:

An independent research firm in Texas was hired to do the laboratory work. The cost of the research was paid for voluntarily by the participating additive manufacturers. Declining to participate and pay for the research were the following companies: Amsoil and Power Service. Because these are popular products it was determined that they needed to be included in the study. These products were tested using funds collected by diesel enthusiasts at dieselplace.com. Additionally, unconventional additives such as 2-cycle oil and used motor oil were tested for their abilities to aid in diesel fuel lubricity. These were also paid for by members of dieselplace.com.
The study was conducted in the following manner:
-The Research firm obtained a quantity of untreated ULSD fuel from a supplier. This fuel was basic ULSD fuel intended for use in diesel engines. However, this sample was acquired PRIOR to any attempt to additize the fuel for the purpose of replacing lost lubricity. In other words, it was a worst case scenario, very dry diesel fuel that would likely cause damage to any fuel delivery system. This fuel was tested using the HFRR at the Southwest Research Laboratory. This fuel was determined to have a very high HFRR score of 636 microns, typical of an untreated ULSD fuel. It was determined that this batch of fuel would be utilized as the baseline fuel for testing all of the additives. The baseline fuel HFRR score of 636 would be used as the control sample. All additives tested would be evaluated on their ability to replace lost lubricity to the fuel by comparing their scores to the control sample. Any score under 636 shows improvement to the fuels ability to lubricate the fuel delivery system of a diesel engine.

BLIND STUDY:

In order to ensure a completely unbiased approach to the study, the following steps were taken:
Each additive tested was obtained independently via internet or over the counter purchases. The only exceptions were Opti-Lube XPD and the bio-diesel sample. The reason for this is because Opti-Lube XPD additive was considered experimental at the time of test enrollment and was not yet on the market. It was sent directly from Opti-Lube company. The bio-diesel sample was sponsored by Renewable Energy Group. One of their suppliers, E.H. Wolf and Sons in Slinger, Wisconsin supplied us with a sample of 100% soybean based bio-diesel. This sample was used to blend with the baseline fuel to create a 2% bio-diesel for testing.
Each additive was bottled separately in identical glass containers. The bottles were labeled only with a number. This number corresponded to the additive contained in the bottle. The order of numbering was done randomly by drawing names out of a hat. Only Spicer Research held the key to the additives in each bottle.
The additive samples were then sent in a box to An independent research firm. The only information given them was the ratio of fuel to be added to each additive sample. For example, bottle A needs to be mixed at a ratio of 480-1. The ratio used for each additive was the prescribed dosage found on the bottle label for that product. Used motor oil and 2-cycle oil were tested at a rationally chosen ratio of 200:1.
The Research Laboratory mixed the proper ratio of each bottled fluid into a separate container containing the baseline fuel. The data, therefore, is meaningful because every additive is tested in the same way using the same fuel. A side-by-side comparison of the effectiveness of each additive is now obtainable.

THE RESULTS:

These results are listed in the order of performance in the HFRR test. The baseline fuel used in every test started at an HFRR score of 636. The score shown is the tested HFRR score of the baseline fuel/additive blend.
Also included is the wear scar improvement provided by the additive as well as other claimed benefits of the additive. Each additive is also categorized as a Multi-purpose additive, Multi-purpose + anti-gel, Lubricity only, non-conventional, or as an additive capable of treating both gasoline and diesel fuel.
As a convenience to the reader there is also information on price per treated tank of diesel fuel (using a 26 gallon tank), and dosage per 26 gallon tank provided as ounces of additive per 26 gallon tank.

In Order Of Performance:

1) 2% REG SoyPower biodiesel
HFRR 221, 415 micron improvement.
50:1 ratio of baseline fuel to 100% biodiesel
66.56 oz. of 100% biodiesel per 26 gallons of diesel fuel
Price: market value

2)Opti-Lube XPD
Multi-purpose + anti-gel
cetane improver, demulsifier
HFRR 317, 319 micron improvement.
256:1 ratio
13 oz/tank
$4.35/tank

3)FPPF RV, Bus, SUV Diesel/Gas fuel treatment
Gas and Diesel
cetane improver, emulsifier
HFRR 439, 197 micron improvement
640:1 ratio
5.2 oz/tank
$2.60/tank

4)Opti-Lube Summer Blend
Multi-purpose
demulsifier
HFRR 447, 189 micron improvement
3000:1 ratio
1.11 oz/tank
$0.68/tank

5)Opti-Lube Winter Blend
Muti-purpose + anti-gel
cetane improver
HFRR 461, 175 micron improvement
512:1 ratio
6.5 oz/tank
$3.65/tank

6)Schaeffer Diesel Treat 2000
Multi-purpose + anti-gel
cetane improver, emulsifier, bio-diesel compatible
HFRR 470, 166 micron improvement
1000:1 ratio
3.32 oz/tank
$1.87/tank

7)Super Tech Outboard 2-cycle TC-W3 engine oil
Unconventional (Not ULSD compliant, may damage 2007 or newer systems)
HFRR 474, 162 micron improvement
200:1 ratio
16.64 oz/tank
$1.09/tank

8)Stanadyne Lubricity Formula
Lubricity Only
demulsifier, 5% bio-diesel compatible, alcohol free
HFRR 479, 157 micron improvement
1000:1 ratio
3.32 oz/tank
$1.00/tank

9)Amsoil Diesel Concentrate
Multi-purpose
demulsifier, bio-diesel compatible, alcohol free
HFRR 488, 148 micron improvement
640:1 ratio
5.2 oz/tank
$2.16/tank

10)Power Service Diesel Kleen + Cetane Boost
Multi-purpose
Cetane improver, bio-diesel compatible, alcohol free
HFRR 575, 61 micron improvement
400:1 ratio
8.32 oz/tank
$1.58/tank

11)Howes Meaner Power Kleaner
Multi-purpose
Alcohol free
HFRR 586, 50 micron improvement
1000:1 ratio
3.32 oz/tank
$1.36/tank

12)Stanadyne Performance Formula
Multi-purpose + anti-gel
cetane improver, demulsifier, 5% bio-diesel compatible, alcohol free
HFRR 603, 33 micron improvement
480:1 ratio
6.9 oz/tank
$4.35/tank



13)Used Motor Oil, Shell Rotella T 15w40, 5,000 miles used.
Unconventional (Not ULSD compliant, may damage systems)
HFRR 634, 2 micron improvement
200:1 ratio
16.64 oz/tank
price: market value

14)Lucas Upper Cylinder Lubricant
Gas or diesel
HFRR 641, 5 microns worse than baseline (statistically insignificant change)
427:1 ratio
7.8 oz/tank
$2.65/tank

15)B1000 Diesel Fuel Conditioner by Milligan Biotech
Multi-purpose, canola oil based additive
HFRR 644, 8 microns worse than baseline (statistically insignificant change)
1000:1 ratio
3.32 oz/tank
$2.67/tank

16)FPPF Lubricity Plus Fuel Power
Multi-purpose + anti-gel
Emulsifier, alcohol free
HFRR 675, 39 microns worse than baseline fuel
1000:1 ratio
3.32 oz/tank
$1.12/tank

17)Marvel Mystery Oil
Gas, oil and Diesel fuel additive (NOT ULSD compliant, may damage 2007 and newer systems)
HFRR 678, 42 microns worse than baseline fuel.
320:1 ratio
10.4 oz/tank
$3.22/tank

18)ValvTect Diesel Guard Heavy Duty/Marine Diesel Fuel Additive
Multi-purpose
Cetane improver, emulsifier, alcohol free
HFRR 696, 60 microns worse than baseline fuel
1000:1 ratio
3.32 oz/tank
$2.38/tank

19)Primrose Power Blend 2003
Multi-purpose
Cetane boost, bio-diesel compatible, emulsifier
HFRR 711, 75 microns worse than baseline
1066:1 ratio
3.12 oz/tank
$1.39/tank

CONCLUSIONS:

Products 1 through 4 were able to improve the unadditized fuel to an HFRR score of 460 or better. This meets the most strict requirements requested by the Engine Manufacturers Association.
Products 1 through 9 were able to improve the unadditized fuel to an HFRR score of 520 or better, meeting the U.S. diesel fuel requirements for maximum wear scar in a commercially available diesel fuel.
Products 16 through 19 were found to cause the fuel/additive blend to perform worse than the baseline fuel. The cause for this is speculative. This is not unprecedented in HFRR testing and can be caused by alcohol or other components in the additives. Further investigation into the possibilities behind these poor results will investigated.
Any additive testing within +/- 20 microns of the baseline fuel could be considered to have no significant change. The repeatability of this test allows for a +/- 20 micron variability to be considered insignificant.

CREDITS:

Good article FF - who did the testing and reporting?*The statements*support:
<ul>[*]Biodiesel can (if from a reputable biodiesel supplier) be*good stuff and is the cheapest additive by far.[*]Marvel and two cycle oil*are not better and maybe bad for common rail engines[*]Valvetec is good at advertising claims[/list]
I see*two issues with the HFFR tests*though:

1. As stated, the samples used were*worst case and supposedly had no lubricity additives added as is or must be*done by a refiner. So why do the tests?
2. The study was paid for by additive suppliers

It would be nice to see a similar study for additives* to function as a biocide.*


-- Edited by sunchaser on Sunday 9th of October 2011 08:07:26 AM

"Biodiesel can (if from a reputable biodiesel supplier) be good stuff and is the cheapest additive by far."

Biodiesel might work on a brand new boat , but the damage to hoses , and gaskets/seals inside the fuel system and the loosening of the gunk in an existing tank and fuel system might prove costly to handle.

AS well as rapidly cause the boat to be unreliable , instead of just wearing out injectors and injector pumps early.

I would choose a less damaging choice like a can of goop.


"It would be nice to see a similar study for additives to function as a biocide."

Practical Sailor has covered this , and found it is required to alternate between two different formulas to get most "bugs".

OF course the best is still a tank constructed so it can easily be maintained, to remove the water.

Waring - We are seeing bio-diesel react as a cleaning agent to the interior of*fuel tanks.

Tom--- The study FF posted has been around for awhile. I recall that it was conducted by or for the trucking industry. When I first saw the study the accompanying explanation said it had been reprinted from a national trucking magazine.

sunchaser wrote:
I see*two issues with the HFFR tests*though:

1. As stated, the samples used were*worst case and supposedly had no lubricity additives added as is or must be*done by a refiner. So why do the tests?
2. The study was paid for by additive suppliers

It would be nice to see a similar study for additives* to function as a biocide.*



-- Edited by sunchaser on Sunday 9th of October 2011 08:07:26 AM

Click to expand...

I hate to be a pessimist, but everytime I see a study funded by a special interest group where they stand to benefit from the positive results (study conducted for the additive manufactures in this case) I have trouble taking it seriously. *If this was stamped with the "UL" label, I might feel more comfortable with the findings. *

But my tanks are in the stern, so no engine room heated fuel to promote the growth of bugs and*here in the PNW with the cooler weather I have never found it necessary to add anything to my fuel.

Larry B.

The BUG population is promoted by the*condensation in*a*fuel tank.

The temperature of an engine room has some effect but the main cause is:

A) partially filled tanks

B) hot fuel being return

It's the introduction of the heated fuel being returned that sometimes reaches over*140 deg F. will raise the air temp in the partially filled fuel tank causing the condensation to develop.

Hummmmmm, steaming fuel tanks. Now that is a new one. I'm still waiting for my racors to show any signs of water. Even my diesel furnace Racor which draws off a tank bottom sump shows no water.

As oft mentioned here, tight deck fills, no water leaking into vents*and clean fuel are the best preventative steps to avoid water issues. When cruising, full tanks are hard to come by.

Now if my business was cleaning tanks, I'd see water, bugs and crud all the time.

sunchaser wrote:
Hummmmmm, steaming fuel tanks. Now that is a new one. I'm still waiting for my racors to show any signs of water. Even my diesel furnace Racor which draws off a tank bottom sump shows no water.

As oft mentioned here, tight deck fills, no water leaking into vents*and clean fuel are the best preventative steps to avoid water issues. When cruising, full tanks are hard to come by.

Now if my business was cleaning tanks, I'd see water, bugs and crud all the time.

Click to expand...

That's my experience too. *I debated installing a fuel polishing system, but I've had such little problem with water or crud in 35 years with this boat, what's the point?

No steaming fuel tanks here either. *My tanks lay flat in the stern, in cradles inches above hull bottom which is bathed in 50F or less degree water year round. The tanks are always nice and cool. *They are easy to pull, once emptied for inspection, which I did 5 years ago. *Result was no rust, very minor sludge at the base of the baffles along the seams, still nice solid steel after 30 years. *Radiator shop boiled them out, treated the outside of the tanks and they went back in the boat.

I change the fuel filters when I change the engine oil and it's good to go. *I would rather not mess with success and as for additives . . . . . who knows?? *If I was in the business of selling them, it would be the greatest thing since peanut butter!! *

Larry B

Upon purchasing my boat and referencing many of the articles on boatdiesel.com I added additional filtration to my engines which now includes 3 filters to each engine and that includes the on engine filter.

First run after purchase I ran about 2 hours before both engine rpm's decayed to about 800 rpm. Both racor vacuum gauges showed excessive vacuum. I replaced both racor filters and the engines ran about 5 minutes before rpm decayed again. We knew we had a fuel contamination issue upon purchase and I had removed all fuel from the main tanks and was running both engines on the aux tank which had been polished and new fuel added. I limped to the fuel dock, filled both main tanks, changed the racors and switched feed to the main tanks. Over the ensuring 8 months I had rpm decay problems but not as bad. I added a chemical tank cleaner, bio guard, and lubricity enhancer.*

Just prior to leaving for our Key West trip in May I noticed the port fuel tank selection valve had partially failed and was porting return fuel to the aux tank even though the left tank was selected. This is a ganged type 6 port valve whereby the handle is attached to a stem that moves two valves one for the return and one for the feed. I installed a 3 port fuel selection valve and rerouted the fuel return lines from the original selection valve, but left the feed portion alone. I continued to have problems with decaying rpm, but not as bad. Finally on the advice of some folks on boatdiesel.com I posted some pictures of my fuel filter elements, both the racor and the newly installed additional filters. Come to find out the filters were not clogged (I was new to this so did not know what dirty filters looked like). I had been chasing the wrong problem from the start - fuel was not contaminated.

After some guidance and testing I determined that both the fuel selector valves were restricting fuel flow to the engines. So not only had the return portion of the port valve failed, both valves were restricting fuel to the engines. No one I've talked to has ever head of this happening.

I've got about 15 hours on the engines since the fuel selector valves were changed and so far no problems. The only issue I have is I can't get much over 2200 rpm from the aux tank fuel and I think this is because I doubled the dose of fuel tank cleaner. The other tanks run fine.

All in all the failed fuel tank selector valves took about a year to figure out. I called the manufacturer and they said this is very rare.

In summary I had assumed contaminated fuel due to the high racor vacuum readings. There were high, but not because of fuel contamination but rather fuel restriction at the selector valves. So a warning, high vacuum means a restriction, but not necessarily due to fuel contamination.

Tim,

*

I have learned "every major problem has a simple solution".

"steaming fuel tanks. Now that is a new one."

This really depends on the fuel injection system style.

The BOSCH style injection has an engine driven pump and high pressure tubing to each injector.
These make almost no heat in the fuel tank as the only return fuel is very minor.,or pump leakage.

Detroit engines use a different injection setup, loads of low pressure fuel is supplied to each injector , and a rocker arm times , pressurizes and injects the fuel. This returns heat , by design to cool the injectors.
Big advantage is in a few hours most of the tank fuel has been thru the filter system .

The newest setup has the fuel pumped to 30,000 psi as it is fed to all the injectors , and a computer fires the $1,000 injectors 1 to 3 times for each power stroke.Lots of heat returned to the tank , and a lightning strike may shut the computer down till replaced.

"The BOSCH style injection has an engine driven pump and high pressure tubing to each injector.
These make almost no heat in the fuel tank as the only return fuel is very minor.,or pump leakage."

Not always true. The Cummins 6BTA (1999 build) I had in my Mainship (and many Cummins 6BTA models) used a Bosch P7100 series injection pump. It flowed 45 gallons per hour thru the system at 1800 rpm and above. Burning 3* gal per hour at that rpm meant the system was returning over 40 gallons per hour. All these engines came with a fuel cooler to keep the heat in the tank down. The byproduct was pristine fuel as it was continously "polished".



*


-- Edited by jleonard on Friday 14th of October 2011 05:14:22 AM

The byproduct was pristine fuel as it was continously "polished".

Ain't the feeling grand , after the first few hours , knowing the engine wont stop?

When ULSD first came out, we in the diesel motor home community encountered seepage problems with gaskets and fuel lines in older engines/fuel systems, roughly pre- 2003. Cummins had problems with the diaphram in the lift pump and initially they sold a replacement diaphram but soon switched over to replacing the whole pump. I was fortunate in that my '02 Cummins ISL did not develop any problems. All of the common RV engine manufaturers - Cat, Cummins, Detroit, saw some seepage problems. I would be very surprised if ULSD did not do the same with marine fuel systems and engines.

Gary

VAtrawlerguy wrote:
When ULSD first came out, we in the diesel motor home community encountered seepage problems with gaskets and fuel lines in older engines/fuel systems, roughly pre- 2003. Cummins had problems with the diaphram in the lift pump and initially they sold a replacement diaphram but soon switched over to replacing the whole pump. I was fortunate in that my '02 Cummins ISL did not develop any problems. All of the common RV engine manufaturers - Cat, Cummins, Detroit, saw some seepage problems. I would be very surprised if ULSD did not do the same with marine fuel systems and engines.

Gary

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FWIW, neither my 1998 Cummins ISB truck engine nor my 1997 Volvo KAD44P boat engine has ever had the slightest problem with ULSD.

FWIW, neither my 1998 Cummins ISB truck engine nor my 1997 Volvo KAD44P boat engine has ever had the slightest problem with ULSD.

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*Neither did my 1991 Dodge/Cummins pickup. It only suffered from old age.

When we got ULSD a few years ago now my old FIAT 8210 fuel p/p started to leak fuel all over the place .
It was opertune in that it was time for the pump to get a good service , so all gaskets, O rings etc were replaced.