I would like to get the Barth wisdom about diesel fuel for 2020 and beyond. First question is there compatibility with pump fuel and the Detroit and Cummins engines of yesteryear? Any additives required?
Once upon a time long ago when Barth was young and life seemed simple diesel was 1/2 the gas prices and had 3 to 5 times life expectancy, 3000 hrs versus >10,000 hrs. Obviously this is different now and I don't think there is current value for diesel below 2 or 3 ton vehicles.
(My hour/life expectation is for farm tractors, which never go down hills and often are well above 50% output. )
Because of the flexibility of a trailer and tow vehicle I will probably remain in that camp But Covid sucks and self-contained is slightly greater in a class A.
Thanks for thoughts and opinions.
Tim

I usually add some 2 cycle oil to my diesel. This was from Rusty worked with fuels.

Thanks Gary! Please note Gary's coach is a cross country traveler so this is a valued comment. At one time Gary was offering it and his other coach for sale, We considered buying it but realized upon inspection that time required for proper ownership exceeded our time capacity. Rusty and I both worked for Shell (Royal Dutch Shell) I in turbine oil research and he in the feet on ground business. Both both boat engines and the genny are lubed with Rotella oil.
Tim

We also use 2 cycle oil in our diesel engines . Tractor , truck , lawn tractor , coach.... Basically any diesel we have . All of our diesels are older with mechanical injector pumps . Occasionally we run Marvel Mystery oil or Lucas diesel treatment through it to clean the system .
When we change our fuel filters , we fill the filter with Marvel Mystery oil to give the system a cleaning and getting the air out of the filter pre-install when possible.

From what I have read, the latest Ultra Low Sulfur diesel has lower lubricity (less slippery) than previous fuels. It is not directly the result of the removal of the sulfur, but rather a side effect the removal process itself.

The concern is the the injector pump, wich has extremely tight clearances, will experience greater wear with the ULSD.
I have not seen actual wear rate comparisons, though.

Many advocate the addition of 2 stroke type oil to improve lubricity, which it does. It is also ashless so it can do no harm when burned. I believe this is a good idea but again, I have not seen actual test data. Certainly, it can do no harm! When I priced 2 stroke oil, I found it was more expensive than I expected.

Cummins recommends Power Service additive (available from WalMart and many others). Used as recommended, it is about the same price as 2 stroke and improves lubricity, as well as other additives to stabilize the fuel. I have used it for the last couple years.

There are numerous brands of fuel additives available. Most are probably good. Shop for sales or buy bulk and save.

WARNING: IMMINENT THREAD DRIFT

I have long been a fan of Shell products. Their additive packages are the best in the industry. AeroShell 15w-50 was the first aviation oil to be approved in all aircraft engines. Semisynthetic, it has the best multivis, anticorrosion, extreme pressure additive package you can get. Actual wear tests and corrosion tests have proved its quality.

Rotella T4 15w40 diesel has been my choice for some time. Again, antiwear and detergent additives have made it a demonstrated superior lubricant. I was recently told that Rotella is now the only remaning diesel lubricant containing zinc.

Zinc compounds (like zinc dithiophosphate) were used for many years as extreme pressure (EP) additives. They were most effective on highly loaded shear surface applications, such as flat camshaft lifters sliding on ramped camshaft surfaces. Pennzoil (sound your z!) was marketed based on the use of zinc additives.

Metallic additives have lost favor recently because they cannot be made ashless, ie they burn to produce metallic oxides. These oxides are solids and with the exception lead oxide, which helped cushion/lubricate valve seats in older engines, they are considered a problem. Especially lead, they are not good for catalytic convertors.

Most modern engines designs have eliminated slider cams and upgraded to roller camshaft designs. These engines do not demand the EP additives of the past and oil suppliers have made changes to reduce their EP metallic additive content. This explains why some of the latest motor oils are not as good for our old 454 engines as their former versions were.
With their proven additive packages, I would recommend Shell products.

New Owner... had some concerns about this exact issue so thank you for the posts. How much 2 stroke oil do you all recommend adding?

Also... No manuals for my unit, so how big of a tank would my 1993 Breakaway with 5.9 Cummins likely have? I am guessing 30 gallons based on my first fill up?

Howdy and Welcome

Your fuel tank should be 60 gallons . Unfortunately , the way the filler neck hose is attached it will only take about 45 gallons . There is a thread on here discussing how you can fix this .

I would add at least one of the small bottles of 2 cycle oil each fill up .

Happy Motoring

I am not a Diesel user but,,,My small engine guy told me not to use marine oil in the lawn mower, trimmer or blower, he did not tell me the difference but indicated it was significant. What do you guys put in your tanks, marine or mower?? I use marine in the boat and mower, blower and chain saw anyway!!!

I use the chainsaw type.

Of all the 2 stroke applications, usually the water cooled 2 stroke runs cooler than the air cooled applications. Larger ones have oiling systems that meter and supply the oil, smaller ones use premixed fuel.

The typical air cooled lawn implements run hotter and usually burn the premixed fuel.

Most of the air cooled applications run constant speed, where outboard motors run at all speeds, often prolonged idling while trolling.

So, does this mean they need different oil? Are these operating conditions so different as to be exclusive?

I can see where premix vs. oil injection system could have different viscosity requirements. With the premix it would not matter much once it is mixed well, but oil too thick might not meter and mix well through the injection system on a cold day on the lake.

As for combustion, both types require ashless oils, often are synthetic blends. I see no reason why they would not do well in all applications.

I suspect the problems may relate to fuel/oil mixture ratios.
Years ago, in the days of marine "white gas" and single wt oils the ratios were often in the 16:1 to 24:1 range. Smoked a lot, fouled plugs but engines ran forever.

Later, OEM recommendations were more like 32:1 or 40:1. They smoked less, burned cleaner, fouled plugs less. Due to improvements in oil quality there was minimal increased engine wear. Win-win.

Ultimately the marine ratios went as high as 50:1. While this did reduce smoke and extend spark plug life, engine wear increased, especially with heavy loads. Manufacturers were more concerned with emissions than extended wear by then.

The metered fuel injection systems were a major improvement. They metered fuel based on throttle position. With idle being lightly loaded, ratios were leaned to around 50:1 with cleaner burn and adequate lubrication. High throttle settings called for more oil volume, more like 32:1. This gave cleaner burn, adequate lubrication and lowered overall oil consumption.

Many years ago, Cycle magazine did a test of 2 stroke fuel/oil ratios. They used an air cooled single cylinder 250cc CanAm trail bike engine on a dynomometer.

They tested 20:1, 30:1, 40:1 and 50:1 premixed fuels. For each test the carburetor jets were adjusted to provide a constant amount of fuel, regardless of the amount of oil in the mixture. The engines were warmed up, then run at full throttle.

The engine produced its highest horsepower with the 20:1 ratio. Almost as good with the 30:1. Significant drop with 40:1 and it seized on the 50:1. After it cooled, they were able to restart it on the 20:1 and it still made more hp than 30 or 40:1.

So, for many years I have run all my 2 strokes with 32:1 ratio. They burn pretty clean, make full power and show little wear.

Only exceptions are my chain saws. They work really hard and get hot so I usually go more like 24:1.

I have never been concerned with what particular oil I was using. Never noticed any difference.

My mower, 4 cycle, takes about a pint of oil and it gets whatever is cheapest with the proper designation. When a quart was <$1 it was different but now the mower is probably on its 8th year and cheap oil ain't cheap.
The cars and boat are different. Wife's BMW gets Castrol since that's what the mechanic of many years prefers for it. My truck dealer used Valvoline throughout the warranty period. My recommendation for Shell goes back to the time we believed in developing a "Head and Shoulders " oil. The term meant the oil would be head and shoulders above the competition. It did, unfortunately it cleaned deposits from the previous oil that wore into the carbon seals for the bearings and results were catastrophic bearing failures. Oil too good, maybe should have been ears and buzz cut above. Tests on gasoline-powered engines were terminated due to boredom. Neither engine nor oil indicated change after several 100 hours, this back in the '60s when the recommendation was 1000 to 1500 miles to change, and a quart was 33 cents and the synthetic would probably be nearer a dollar. Short answer, make sure the oil meets the needs, is available and you have some on hand.

Have always used 3 ounces per gallon for premix. My bass boat Mercury outboard uses a lot more, really increases the oil when run at wide open throttle, that is most of the time. Am not able to determine how much that it uses as a mixture.

Marine 2 cycle oil has the designation TC3, as I understand prior to this additive, high horse power outboards failed often due to oil problems. Anyone know what TC3 is or did to oil?

We have used the power service additive since about 2009 at its recommended ratios but also add 2 cycle oil at about 300:1 as well. (our Barth has a cummins 8.3)
Our outboard--- a 2006 E-Tec 90 hp runs on Evinrude XD100 oil--- which when I have checked is automatically mixed in the order of 100:1 ratio. Our 10hp Johnson kicker (1960 version--purchased by my Dad in 1959???)--has been run on XD100 for about 8 or 9 years now mixed a ratio of about 75:1---however it gets light use (low throttle) and has so far done very well with no observable adverse changes in performance.

Bud