Adding oil to diesel fuel?

[Chotu]

Modern engines are designed to run on modern fuels. This is completely unnecessary in my opinion. But this is greatly debated on diesel forums.

It may help older diesels not designed to run on modern ultra low sulphur fuel. I add a little 2 stroke on my 2002 Cummins turbo diesel in the hopes it'll help the high pressure pump last a little longer.

No idea if it's working or not.

[a64pilot]

Originally Posted by O_salt

A friend of mine has bought a new Volvo diesel engine and the salesman / Installer is telling him to add 1% 2-stroke motor oil to his diesel fuel to help lubricate the engine.



Has anybody else ever heard of this?

Yes, it comes from the concern of ULSD being a “dry” fuel and having poor lubricity, that is a word by the way

It’s also aggravated by common rails extremely high pressures and susceptibility to wear.

There are much better additives than two stroke oil.

In my opinion the concern of ULSD’s poor lubricity is well founded.
This isn’t a new test, but it was very professionally done in my opinion.
http://www.jatonkam35s.com/DeuceTech...itive_test.pdf

[Dsanduril]

Interesting study A64. I'd get more value from it if they also published HFRR results for samples direct from the pump (rather than just saying "there have been many documented cases..."). This study of last year's diesel state around the world shows that only the biodiesel and Opti-lube got below where actual fuel pump samples land today (and even at the time of the study).

The takeaway from all of it put together - if you want to use anything to improve lubricity, use bio-diesel. It had the best performance in the study you linked. In diesel statistics it also has the best values. And, for the OP, Volvo specifically allows the use of bio-diesel in the engine.

HVO (hydro-treated vegetable oil)...
NOTICE! Volvo Penta approves usage of neat HVO and GTL that complies with EN 15940, as well as HVO and GTL blends into diesel fuel complying with the quality requirements above[emphasis added]

[thinwater]

Originally Posted by oldjags

A lot of manufacturers used to (maybe still do?) specify that you had to use their brand of lubricants and filters or else the warranty was void. It was just a ploy to help sell their over-priced private-label stuff. But, who wants to take the chance that a warranty claim might get denied because you used Mercruiser oil or some generic equivalent in your Johnson outboard?

As others have pointed out, this has been plainly illegal since the Magnuson Moss Warranty Act of 1975. I doubt you can find that language in a manual. IF you can, please post, because we are interested.


You do have to use oil that meets the stated spec.

[newhaul]

Posting this for information only hope it helps
https://www.google.com/url?sa=t&sour...LwTPmPKGrRnpjW

[a64pilot]

Originally Posted by Dsanduril

Interesting study A64. I'd get more value from it if they also published HFRR results for samples direct from the pump (rather than just saying "there have been many documented cases..."). This study of last year's diesel state around the world shows that only the biodiesel and Opti-lube got below where actual fuel pump samples land today (and even at the time of the study).



The takeaway from all of it put together - if you want to use anything to improve lubricity, use bio-diesel. It had the best performance in the study you linked. In diesel statistics it also has the best values. And, for the OP, Volvo specifically allows the use of bio-diesel in the engine.

I’d avoid Bio on the boat like the plague, primarily because of “bugs”.

However Bio is problematic because there are no standards, yes most of it is good, probably vegetable based, Soy is often excellent.
But some of it can even be animal fat based, and they are completely different things.

I know because I went through an attempt with Pratt & Whitney and General Electric to certify an aircraft for flight with a form of Bio fuel.
We never finished, but it was an eye opening experience, taught me a whole lot about “Bio”.

I used to run Bio in my Duramax Diesel when I could find it, up to B20 for road use can be an excellent fuel, much better lubricity and I believe Cetane as well. Lubricity was what I was after.
The early Duramax Diesels had fuel injector issues, and as they were buried deep into the head for noise reasons, they were a real bear to change out, and they were real expensive, so we did what we could to make our injectors last.

[Dsanduril]

Originally Posted by a64pilot

I’d avoid Bio on the boat like the plague, primarily because of “bugs”....

Don't disagree with you there, but 95% of the alternatives in the study you linked get you no better lubricity that what you can get at the pump. So you have to decide which you care more about.

Curious if we worked on opposite sides of the same study as I worked for a bio-fuel manufacturer that got a 10% mix of their fuel certified a couple of years ago. Ended up with a two-year trial on Cathay Pacific on flights from France to Hong Kong and certification for all flights in Brazil (American bio-fuels company, Brazilian production facility). Trial ended last year, but I've been at sea so haven't really kept touch.

[mvmojo]

I've heard that large mega yachts, etc., actually mix their filtered waste oil with their diesel fuel, up to about 10% by volume. They have a tank that they dump waste oil from oil changes in, it gets filtered and then injected into the fuel stream. Never seen this, but have heard it from a number of sources. Anybody know if it's true???

[thinwater]

Originally Posted by mvmojo

I've heard that large mega yachts, etc., actually mix their filtered waste oil with their diesel fuel, up to about 10% by volume. They have a tank that they dump waste oil from oil changes in, it gets filtered and then injected into the fuel stream. Never seen this, but have heard it from a number of sources. Anybody know if it's true???

In fact, this is specifically forbidden by ISO 8217. This has been beaten to death by researchers for decades and you do NOT want to do it. I worked on both sides of this issue for decades, and it is settled from an engineering perspective.

Used lubricating oils (ULO): The fuel shall be free from ULO, and shall be considered to contain ULOwhen either one of the following conditions is met:
Calcium > 30 and zinc > 15; or Calcium > 30 and phosphorus > 15.

This is also a strong case for not adding lube oil.


There are companies that sell blending equipment. That is what we call crooked business.

[skipgundlach]

Originally Posted by Compass790

Some trucks use filtered used sump oil as a part mix in their diesel so 2 stroke must be ok

(clips before and after that)

Some years ago I was considering what to do with my oil changes and went researching.

The US military specifies it as approved, up to whatever percentage it was. Given our 2.5G change, less because of leakage chronic to the Perkins 4-154, we'd have maybe 2-5% oil change to diesel.

I elected not to do it for reasons having more to do with operating temps rather than engine concerns; look up the milspec on the subject (I no longer have the links)...

[mvmojo]

Thanks for the clarification. As I said, I've heard about this for years. Likely not worth doing it on recreational sized boats, but for those big ship diesels where lube oil is a significant operational cost it would make sense IF it was legal and IF it didn't cause more problems than it was worth!

[DougR]

I believe the technical literature from Volvo Penta is very self explanatory and clear when it comes to the addition of extra additives into the fuel stream. In general it is not necessary, and in some cases it may be harmful.

- The addition of 2 stroke oil, ATF, and other lubricity " enhancers" is typically not necessary as the fuel already contains sufficient lubrication.

- The idea of blending used engine oil into the fuel stream harkens back to the old days before emission rules and then typically only with low RPM engines burning heavy fuels.

- As shown, VP approves the use of Bio fuels up to a certain percentage mix, but they also recommend against the long term storage of Bio fuel in fuel systems of boats. ie., drain or burn off your Bio before winter storage as it can separate and gum up the fuel system.

- In certain applications and with specific engines, VP (and other engine manufactures) recommend the addition of supplementary lubrication to the fuel stream to protect injection system components. This normally occurs when the engine is used in a military application where the fuel in question is one of the various jet engine fuels, like JP4 or JP5. These jet fuels are very "dry", that is lacking in lubrication, and additional lubrication is required or rapid fuel system failure occurs.

DougR

[thinwater]

Originally Posted by mvmojo

Thanks for the clarification. As I said, I've heard about this for years. Likely not worth doing it on recreational sized boats, but for those big ship diesels where lube oil is a significant operational cost it would make sense IF it was legal and IF it didn't cause more problems than it was worth!

And on those big ships, the cost of an engine is $$$$. ISO banned it for good reasons, based on lots of testing. This is an old wives tale and a dangerous myth. You probably won't see and obvious failure, just as you wouldn't if you stretched the oil change interval or used a cheap filter, but the cost will outweigh the benefit.


So are we done? BTW, US military practices are not all focused on maximum equipment life.

[Lippe]

Moderm diesel engines are highly sensitive machines that are designed with very small tolerances. Engines are supposed to operate with fuels that are commonly availalbe and recommended by makers. No additives are needed except if that is recommended in engine manual or maker's service bulletin. As far as I know there is no such recommendations. Fuel makers and engine makers as well as component makers are working closely together in order develop products that fit together. Be careful when making feeling based statements "cannot be harmfull" when you dont know issue. Although it may not be harmful (but unnecessary) for an older product the case is not necessarily same with a modern dielsel engines.

[hellosailor]

Diesel is among the things that are often called "fuel oil" so the idea of, well, adding more or other oil to THE fuel OIL isn't so crazy. I'd normally join the camp that says follow the factory manual, there's usually a reason for whatever they say. But, that reason may be something like "adding oil is going to change the emissions, we can't have that" so the factory may be saying not to add oil for political/environmental reasons, not strictly performance issues.

But I'd tend to expect that following the manual will be "good enough" whatever their reason for doing it that way.