Used engine oil mixed with diesel fuel.

I am planning to change oil in main engines and baffled that getting rid o the used oil can be an issue while doing the loop. If I was home I would just bring used oil to a parts store or Wall Mart. But here as a transient at a marina, without a car it starts to be an issue. Uber drivers would probably freak out if I showed up with 12 gallons of used oil.
So I wondered what the consensus is for filtering the oil with a paint filter and pouring it into fuel tank and burning it. I googled it and discovered this can be done, but wondering if anyone has tried it and with what results.
The recommendation is to add less than 10% oil to fuel to start.

It has a similar energy density and the engine will run on it, but it does not burn as cleanly and can dirty things up. I wouldn't do it.

Id be surprised if a marina with an oil tank wouldn't let you dump oil, even as a transient. The ones I know do. Heck, you pay more per day than home tenants!

It's not that hard to find places to take the old oil in my experience. And it's not like carrying a few gallons aboard until you find a place to properly dispose of it is a big deal...

Between Toronto and Bahamas I've carried the stuff for weeks to find a legit place to get rid of it. I'd rather carry it than burn it in my engine.

For many years I burned my waste oil. Now I centrifuge and have no waste oil. The waste oil mix was usually 10 gallons of oil to 100 gallons of fuel or more. I run clean oil and before I used the centrifuge I used a bypass filter that filtered to 1 micron (that usually left particles smaller than 5 microns). If I was going to burn waste oil from an engine with full flow filters, usually 30 micron, I'd filter it through a 1 micron before adding to the oil.
The injector pump has tight clearances and too much debris in the fuel will wear it out faster.

I've probably burned thousands of gallons of waste oil without problems. Usually in ship engines or Detroits.

Along the loop most marinas that do repairs have disposal of oil available - free with overnight dockage usually and u may stay more than 1 night to do the oil change anyway. Lots of marinas have a courtesy car to go to auto parts store as an alternative. If the containers are clean, don’t see why Uber/Lyft would complain. If all else fails, tip well!

Absolutely not IMO.
There’s additives in lube oil that you don’t want in your fuel oil.

Carbon soot is abrasive. Old lube oil has lots of it. What doesn't clog up your fuel filters will pass through your injection pump, injectors, and cylinders. Plus what settles out in the bottom of your fuel tanks adds to the other crud in there.

Old Detroits are famous for burning about anything. But in their shop manual they specifically warn against this practice.

At a minimum, it's an old-school trick for old-school engines. Not that either is bad, but fewer and fewer engines are old-school.


I would never even consider the practice for a common rail or other high pressure injection system. That rules out any engine built after maybe 2000-2005, but it will vary by brand and HP range.


I doubt there is any engine manufacturer (for a small craft), at any time in history, anywhere in the world, who would condone such a practice.


But I suppose it's an approach that could work for garbage disposal too? You could mix a little bit of your garbage in with your food, and might not notice it. Just think of the saved trips to the dump.

twistedtree said:

But I suppose it's an approach that could work for garbage disposal too? You could mix a little bit of your garbage in with your food, and might not notice it. Just think of the saved trips to the dump.

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I just did a Danny Thomas reading that. Thanks.

Injectors run at such high pressure that even specs of carbon less than a half a micron would eventually be abrasive enough to do injector damage. I wouldn't do it.

Living in Wisconsin there are lots of home mechanics using drain oil to heat garages and shops so disposal around here isn't a problem. I have never, yet, boated the east Coast so I can't help you there.

pete

As an expert in engine lubricants I would NEVER recommend putting a modern engine oil in diesel fuel. A typical API CJ-4 or CK-4 engine oil has anywhere from 14-18% of additives plus viscosity modifier, which is a olefin copolymer (like a rubber). All engine oils have a metallic additives (zinc dithiophosphate, Ca and Mg detergents) which contribute about 1% of sulfated ash. Sulfated ash is what's left when you burn off everything else. I actually wouldn't worry much about the wear metals (they're in the parts per million level) but the additives will contribute to deposits on the pistons and can eventually increase the risk of ring sticking over the long term. You might get away with it occasionally but its like smoking, how much do you want to increase your risk?

Racor makes filters with various filtration
efficiencies, but its standards for non-OEM (Original
Equipment Manufacturer) are 2, 10, and 30 micron
filter elements. The actual efficiency ratings for these
are 98%, 95%, and 90% respectively. Racor also
makes use of a 7 and 20 micron filter medium which
are used to meet certain engine manufacturer’s
requirements for a final filter and a primary filter.

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Why do you filter diesel? The obvious answer is to prevent particles greater than a certain micron from getting into the engine fuel delivery systems.
If the filter is good enough to filter diesel then why is it not good enough to filter used oil.
The opposition to burn used oil has not explained the simple concept that whatever goes through the filter will be filtered the same. So where is the perceived danger of damage engine parts come from. Why do so many think oil will carry more larger microns through a filter than diesel.

The last marina we were at charged $2/gallon to have someone pick it up.

Soo-Valley said:

Why do you filter diesel? The obvious answer is to prevent particles greater than a certain micron from getting into the engine fuel delivery systems.
If the filter is good enough to filter diesel then why is it not good enough to filter used oil.
The opposition to burn used oil has not explained the simple concept that whatever goes through the filter will be filtered the same. So where is the perceived danger of damage engine parts come from. Why do so many think oil will carry more larger microns through a filter than diesel.

Click to expand...

Read post #13.

The issue with burning compounded oil (used or fresh) has nothing to do with particle size. You could filter to 10um and additives are not removed, in fact we (additive suppliers) often filter to that level as to the lubricant blenders. It is the chemical nature of the lubricant additives that are a concern. This is why as engines begin to burn more oil they often encounter ring sticking. Additives used for fuels are different from those used in oils. First thing is that they are ashless (don't contain metallic components). In short, they're designed to be combusted. Lubricant additives are designed to operate at temperatures below 150C. As you exceed that they begin to thermally decompose (doesn't matter whether its a synthetic or mineral oil).

SKI from the Wilmington, NC area is an experienced engineer with his latest experience in diesels, particularly gensets.

He tried some oil in his fuel on a landslide genset he used for emergency backup andif I remember correctly, he said it trashed his genset motor.

May want to wait for his comments if he see this thread.

Hard to imagine that with Slowmo's input and a little research....... one hasn't figured out that while it is done by some....probably in certain situations....for most of us it's a bad gamble.

For a couple of years put about five gallons of used oil in my 190-gallon tanks for the FL120s to eat, but then stopped in favor of disposal ashore. I would not do it for this Yanmar. AND when I installed the Floscan, the directions specifically mentioned the detrimental effect the practice could have on the FS sensors.

A suggestion for getting rid of old engine oil:

Google to find a "Steamboat Club" or "Hobby Steamboats" or "Hobby Locomotives" (the kind large enough to ride on).

Offer to donate your oil free to any member close to you, to pick up. They'll burn it in their steam boiler. It beats paying for diesel at the pump.

Besides all the solids from combustion and additives in the oil, there can be corrosive acids that accumulate in the oil over time. That is the culprit in the discussion about whether to change oil before putting an engine into storage or after it comes out of storage. I think the majority would say change before storage to get those corrosive compounds out before sitting for a period of time. Sulphur in the fuel will combine with condensed water and form a mild acid which can go to work on close tolerance fuel injection components and damage them. Maybe this is not a big problem since Lepke is just centrifugeing his oil to clean the particles out but wouldn’t do anything for liquids ???

I wouldn’t burn used engine oil in any new high pressure common rail system for sure and probably wouldn’t on any system.

I worked for a company in the 90's that got involved with a company selling waste oil heaters. They were a fuel oil heater modified to burn waste oil. Company bought 15 or 20 heaters thinking they would be easy to sell to the trucking companies-lots based in the metro Atlanta area. Should have done their research because all the big trucking firms mixed their waste oil into truck fuel. Didn't sell more than 1 or two. Granted this was 25 years ago and have no idea if it is still the norm with the newer engines of today. Turns out the heaters were super high maintenance-hard to keep burner nozzle clean and the fuel pumps didn't last trying to pump dirty oil. Probably a good reason not to burn oil in a modern engine, wouldn't risk it on my old Lehman either. As far as I know they still have a stack of heaters in the back corner of the warehouse.

rns out the heaters were super high maintenance-hard to keep burner nozzle clean and the fuel pumps didn't last trying to pump dirty oil.

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My son has been heating his automotive repair shop for about 15 years with only waste oil.
He never had a nozzle or pump issue. The only problems were clogged pick up screens and of course filter changes.
He burns used motor oil, tranny fluid, brake fluid, etc. If you look at the chimney there is no visable smoke.
Waste oil heaters have come a long way.

I was trying to figure out why someone would want to do this and had to go back to the first post. I guess it’s for convenience? I have 12v71 Detroits and change nearly 15 gallons every 100hrs and have never had a problem disposing of the oil and the 4 huge filters when traveling. Either a marina will take or I can get a lift to an Autozone or other parts seller who will take it. Sometimes I have to hold it for a week or so, but so what? Even here in the Exumas I can find a place to take it, if I want to pay a bit: $2 a gallon, the same price as for a single bag of trash in Georgetown Harbor. It’s in 5 gallon pails with caps so it’s not like it can’t sit in the cockpit or engine room indefinitely until I find a place to accept it.

for eons i have been using a by-pass filter system that is called, "GULF COAST OIL FILTERS," they have one model that filters oil, and another for fuel...they also sell thier own filter replacemets. since mine were new, i have the purchased the 6" bounty paper towels at Costco, i think they filter down to abt 1, to 1.5 microns...been on our 40ft skookum built in port townsend, wa. for 30 yrs, between oil changes is about 300 to 350 hours, have sent samples in, and the oil is very clean! the name is derived from being produced on our southern gulf coast!
i have a 1992 dodge/cummins pickup, with a "frantz" toilet paper oil filter on the dodge since it was new, i change the toilet paper roll every 2500 miles, and the oil at abt 15,000+ miles! the first several times, i sent samples in, and there never was anything in the oil, no blowby, silicon/dirt, water, nada ever! have always used Scott 1000 toilet paper! the website to buy the frantz toilet paper filters, for oil/fuel, is "WE FILTER IT" they have kits, i would buy a gas or oil filters, and buy all the hose/fittings, etc, locally! have been using the Frantz since 1962! have had mechanics tell me that the newer engines are more sophfisicated, etc, so my answer is always, were only filtering the oil from the engine, then back to the engine, for fuel, from the fuel tank to the engine thru the smaller "pre-filters" my email is garbage7@wavecable.com. i also flush the volvo single and genset we have, with fresh water every time we park it in our boat house! i run fresh water thru to flush the salt water out! salt water helps cause corosion!...clyde

it`s a little different than your question, my wife is from germany, in the cold winters, they added abt 10% gas to their diesel fuel...clyde

Waste engine oil is useful for fueling oil-fired steam engines.

Would not think of adding it to the boat's diesel fuel.

Have no oil-disposal concerns since I let the boatyard/engine mechanic deal with it every year or so.

i see, you don`t do your own work, you let someone else do it! waste oil also runs heaters in large shops, in some places used oil is used on dirt roads, to keep the dust down in the summer! when i was a kid, used oil was re-refined, and sold cheep in service stations ($0.25) a quart! as i said, in europe most add 10% gas to diesel in the winter! i rremember in warm states, like california, they sprayed used oil along side the roads to prevent the grass from growing!...clyde

But I suppose it's an approach that could work for garbage disposal too? You could mix a little bit of your garbage in with your food, and might not notice it. Just think of the saved trips to the dump.[/QUOTE]

Good one.

funny...i was involved in the family garbage business for approx 40 yrs! one thing, i commercial fished for 20 years, from the seattle area/san juans, to the kodiak area, always was out of bed by 02:30, during summer fishing season, after unloading our catch, cleaning up the boat, eating dinner, we usually got into our bunks about 10pm or later, so when i started to haul garbage, getting up early was`nt new! i never ate much more than a coupla pieces of toast before i left the house, cause it`s difficult to work/lift etc, this was before containers, so it was by hand lifting cans, which is difficult after eating much! i would haul commercials early, and start the residences about 0700! i remember the biggest resteurant had about 18 cans, and it was difficult to smell all the roasted beef/garlic bread, etc, i usually stopped to eat at a small place around 11am...