Best diesel lubricity formula

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
One other thing to note is that the ASTM D975 specs are consensus and not regulatory. . and since it is so difficult to get specs from any supplier, who knows what is actually in the fuel.

Two things

First, lubricity numbers for bulk shipments are a contractural arrangement for meeting spec. The little guys like us are several steps removed from diesel fuel spec and delivery testing results.

Second, who says there is a problem? Two groups, one being the after market additive suppliers and the other the end users who are looking for reasons as to why their old and infrequently used diesels don't last forever.

Having operated and maintained diesels long before ULSD was mandated, I saw many fuel system part failures that came from poor design, poor filtering, bad fuel, low usage and sloppy maintenance.

None of my above BS means the importance of lubricity is not monitored closely by refiners and end users. But how good is good enough?
 
Two things

First, lubricity numbers for bulk shipments are a contractural arrangement for meeting spec. The little guys like us are several steps removed from diesel fuel spec and delivery testing results.

Agreed. I just think it makes sense to be prudent in prevention if the current fuel specs for ULSD are marginal for older mechanical injection engines, and if a lubricity additive has no down side and minimal cost.

I did find that Florida has legally mandated D975 for their fuel regulations.
 
Last edited:
Agreed. I just think it makes sense to be prudent in prevention if the current fuel specs for ULSD are marginal for older mechanical injection engines, and if a lubricity additive has no down side and minimal cost.

I did find that Florida has legally mandated D975 for their fuel regulations.

Nothing the matter with being prudent. You are dogged, that's good. Optilube seems the better of the after market products for lowering lubricity. From my readings bio diesel is the liquid of choice, any locations in your area where you can get it? Very common in BC.
 
Last edited:
Second, who says there is a problem? Two groups, one being the after market additive suppliers and the other the end users who are looking for reasons as to why their old and infrequently used diesels don't last forever.

Having operated and maintained diesels long before ULSD was mandated, I saw many fuel system part failures that came from poor design, poor filtering, bad fuel, low usage and sloppy maintenance.

The after market additive supplier has a vested interest in selling his snakeoil so hardly a reliable source.

The end users as you yourself said have poor filtering and bad fuel issues as well as sloppy maintenance and low usage leading back to bad fuel with poor filtering.

The end users need to look at their own fail instead of blaming the fuel and praying for that miracle elixer.
 
The end users as you yourself said have poor filtering and bad fuel issues as well as sloppy maintenance and low usage leading back to bad fuel with poor filtering.

The end users need to look at their own fail instead of blaming the fuel and praying for that miracle elixer.

Why this may be true in some cases, in the case of my failed fuel pump, these are very well cared for engines. The fuel filters have vacuum gauges, are changed annually or sooner at 200 hrs and never show abnormal vacuum levels. I routinely get 200 hrs out of my filters without a problem. I use 30 micron racors and 2 micron spin-ons. There has never been signs of water in my fuel filter bowls or signs of algae. I go through typically 1500 to 2000 gallons a year so the fuel is not old.

I am similar in caring for my aftercoolers and sea water systems - new impellers every year, Rydlyme flush entire seawater cooling system bi-annually, flush and change coolant on schedule, R&R aftercoolers every 3 years for clean and inspection, etc.

This is the reason I looked into lubricity in some depth as there were no obvious causes or maintenance issues leading to a fuel pump failure at 2000 hrs. Without a cause and good service intervals, I have decided in the ULSD environment, on older 3208s, a lubricity additive makes sense.
 
Why this may be true in some cases, in the case of my failed fuel pump, these are very well cared for engines. The fuel filters have vacuum gauges, are changed annually or sooner at 200 hrs and never show abnormal vacuum levels. I routinely get 200 hrs out of my filters without a problem. I use 30 micron racors and 2 micron spin-ons. There has never been signs of water in my fuel filter bowls or signs of algae. I go through typically 1500 to 2000 gallons a year so the fuel is not old.

I am similar in caring for my aftercoolers and sea water systems - new impellers every year, Rydlyme flush entire seawater cooling system bi-annually, flush and change coolant on schedule, R&R aftercoolers every 3 years for clean and inspection, etc.

This is the reason I looked into lubricity in some depth as there were no obvious causes or maintenance issues leading to a fuel pump failure at 2000 hrs. Without a cause and good service intervals, I have decided in the ULSD environment, on older 3208s, a lubricity additive makes sense.


What are your thoughts on why only one pump failed? How many of the injectors have failed due to wear?
 
So why do you pro-additive evangelists think that for the very old school Detroit 2 strokes, wherein fuel plays a very important role in cooling and lubrication, the manufacturer specifies as low a sulphur content as possible and no additives?
 
What are your thoughts on why only one pump failed? How many of the injectors have failed due to wear?

I dont know why only one pump failed. Further, only one cam lobe failed, and the other lobes looked normal wear patterns. No injectors have ever failed before the cam lobe failure, they were all replaced only due to debris from the failed cam lobe.

Perhaps it was a random metallurgical failure. It is hard to tell because once the primary running surface on the cam started to wear at the highest loading point then that is where ultimately significant fracturing and wear of several mm off the the lobe occurred.
 
Last edited:
So why do you pro-additive evangelists think that for the very old school Detroit 2 strokes, wherein fuel plays a very important role in cooling and lubrication, the manufacturer specifies as low a sulphur content as possible and no additives?
Probably because they approve ASTM D975, grade 1D & 2D fuel if the lubricity max wear is 460micrometers for S53, S71, S92 and S149 engines.

So no need for lubricity additives.

Reference: MTU Fluids and Lubricants Specifications manual, A001061/35E, table 18.

Note that old lubricity additives were metal based and lead to ash forming deposits causing injector fouling and cylinder wear or were halides that caused corrosion.

New lubricity additives are fatty acid based and are burnt more thoroughly during the combustion.

Detroit and MTU have some pretty good manuals online.
 
I dont know why only one pump failed. Further, only one cam lobe failed, and the other lobes looked normal wear patterns. No injectors have ever failed before the cam lobe failure, they were all replaced only due to debris from the failed cam lobe.

Perhaps it was a random metallurgical failure. It is hard to tell because once the primary running surface on the cam started to wear at the highest loading point then that is where ultimately significant fracturing and wear of several mm off the the lobe occurred.

"only one cam lobe failed, and the other lobes looked normal wear patterns. No injectors have ever failed
Perhaps it was a random metallurgical failure"

Yes - I would agree with your diagnosis as the best fit description.
 
So why do you pro-additive evangelists think that for the very old school Detroit 2 strokes, wherein fuel plays a very important role in cooling and lubrication, the manufacturer specifies as low a sulphur content as possible and no additives?

Each of the engine manufacturers spec their fuel requirements D975 or EN590. As long as the fuels meet the specs no additives are required. The ulsd refining process removes the lubricity and it it must be added back using additives by the supplier.

What I worry about is I travel to many islands and up and down the east coast. it can only take one bad batch of fuel with subpar lubricity to damage an engine. If the correct additives were not blended in fuel I took at Staniel cay or Lucaya or some other unknown marina I worry.

Same thing for me with biobore. I use it from time to time or when my fuel will sit. Have never had an algae problem. But worry about getting some water in fuel when the tank in treasure cay gets low since they are not my regular supplier
 
So why do you pro-additive evangelists think that for the very old school Detroit 2 strokes, wherein fuel plays a very important role in cooling and lubrication, the manufacturer specifies as low a sulphur content as possible and no additives?
Perhaps you have an answer for us?
 
"So why do you pro-additive evangelists think that for the very old school Detroit 2 strokes, wherein fuel plays a very important role in cooling and lubrication, the manufacturer specifies as low a sulphur content as possible and no additives?"

DD were designed in the 1930's and what was considered "normal" diesel then probably had very different sulfur content than todays.

Some folks feel an additive is a insurance against fuel depot screw ups , others don't.
 
Citing the 2007 Spicer study, Stanadyne products are of marginal benefit as compared to Optilube for improving HFFR results. What parts on your Cummins benefit from lubricity after market products?



Again............INJECTORS
 
Back
Top Bottom