Buring used diesel oil as a fuel?

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Fordiesel69

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Stupid question, I know........

But, I know of a logger that when he changes out his 15 gallon sump of diesel oil, he will then put 5 gallons of used oil per 1 tankfull of diesel fuel. He said you will not be able to see the increased exhaust emissions because it is way dilluted. This sounds like a great way to get rid of your old oil, but isn't this harming the engine/injection system?
 
Yes, you can burn waste oil diluted in your fuel. Cummins had a system that they sold for a number of years as factory equipment that did this. There are several aftermarket systems sold that burn wast oil as well. From your user name, I'm guessing you have a Ford with a Navistar 6.9L in it. If that is the case, you can burn quite a bit of wast oil without worry. The biggest thing I would worry about is if the truck doesn't get worked hard enough to warm it up, you'll carbon up the injector tips.
 
In a common rail I would be much more careful, but I wouldn't see a problem burning waste oil in that either. The bigges thing with a common rail fuel system would be filtering as much of the particulate matter out. I'm guessing you are running either a 6BTA Cummins or a Duramax, both of which use a Robert Bosch CP3 fuel system. The CP3 high pressure pump has a lot going on in them and they are not quite as forgiving as the older mechanical pumps in some ways. I'd run really good fuel filters, or off-line filter the used oil with a really fine filter, after that have at it.

Again, watch your treat level as you don't want too much oil in the fuel because you could get carbon build up.
 
I would say use the same treatment as I described for the CP3 fuel systems. I'm not familiar enough with the VM engine in those Liberty's to make a more thorough statement. However, almost all common rail fuel systems are running fairly high pressures, about 20,000 PSI+ so any kind contaminate going through the pump is pretty bad.

The older injection pumps are a little more tolerant since they aren't required to generate pressures as high as common rail pumps. This means the pump clearances are more tolerant to some degree. I would prefer the oil be off-line filtered with good filters, however I know many people that rely on the fuel filter alone and haven't had any problems. I would think that in all reality the mixture ratio is more important.
 
Not really sure what size tank you have, but around .5-1 gallon in 20-30 gallons of fuel is probably plenty safe. The cleaner the oil is, particulate wise, the higher the ratio I think would be acceptable.

I would start with a few quarts and see how it reacts, you can always use a little more or less if you need to. Again, you just don't want to run so much oil that is starts beating up on the high pressure fuel pump.
 
No that's great thanks. Was simply wondering what sort of ratio you figured was safe. I have a bunch of used oil right now (that I usually dump at a mechanic friend's shop). Any suggestions on how to filter it properly? I have a bunch of coffee filters or am I WAY off base? And thanks.

John.
 
Sure, coffee filters would work but you would probably end up going through a lot of them. If I was serious about burning my old oil in my fuel, I'd invest in a MG and just use TP since it's inexpensive. You could also use the TP longer since you are just filtering it, no worries about it plugging up. Filtering and filter changes can be done at your convenience.

Most people don't filter the used oil at all, so anything that you do is going to be an improvement. I tend to err on the side of caution on issues like this, so take that into consideration as well.

I used a friends Frantz and a MG in parallel to filter used oil that I mixed with diesel to put in my heaters I used in the big shop. I have since broken down and spent some money and hung two nice gas heaters in that building so I don't burn the waste oil. And now that my friend has taken a brake from racing, I don't turn the heat on out there much since it's just storing my junk these days.
 
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MG? TP I get but not the MG reference, sorry.

John.

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He was talking about a Motorguard Remote Bypass Filter. This is a fairly expensive option but if you were commited to burning waste oil from now on it might be okay. As a matter of fact it might add some needed lubricity to the ULSD. However I'm not sure how good it would be for the Exhaust Cat on the CRD.

Years ago we just dumped the waste oil into the underground fuel tanks and relied on the filters on the fuel pumps to take care of any large particles but we were running mechanical injection systems and didnt have a cat on the exhaust. These days we sell the oil to recyclers.
 
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I think that a smaller MG is 130 dollars from Ralph Wood, not real expensive.

Gene K, yes the CAT and/or DPF (diesel particulate trap) can be affected severely with burning wast oil. That is why I was trying to emphasize closely watching the mix ratio. I would tend to agree with you that it would help the lubricity of ULSD, although I still think a purpose blended additive is far more effective.

The cat will live a long and happy life even with burning small amounts of waste oil with the fuel. Just don't over do it. The cats are actually built with quite a bit more tolerance than the mfg's usually let on. They have to allow a higher limit than they advertise because of fuel quality variations and climate conditions.
 
IIRC, Cummins states a 5% blend of WMO in fuel...for the older "mechanical" engines (have not seen any specs or recommendations for the CRD)

One thing we had a discussion about (elsewhere) was the fact there could be wear metals in the used oil...most guys leave their oil sit for a week or so to leave the nasty stuff settle out...

I built a filter setup, but I have never used it...it consists of a 5gallon bucket, 10 micron filter, and shutoff valve...all gravity. I built it, then had second thoughts since the HPCR is a lot more finicky...even though I'm running a FASS with a 3 micron absolute filter. It was too much money to take the chance.

Also, some synthetic oils don't burn, and will simply (and literally) run out/drip out the tailpipe.

steved
 
sdeeter, that is why I recommended a bypass filter like the MG as it is submicronic, that is, less than 1 micron. A 10 micron oil filter (which is probably 10 microns nominal) is about the same as a good full flow engine oil filter. A MG, Frantz, etc. will work much better in this application.

Cummins does not state, but RECOMENDS blends up to 5% biodiesel. They do not impose limits and they do allow 100 biodiesel. The only liability is if you have a failure directly related to biodeisel it MAY not be covered under warranty. I know of a guy who was running 100% bio and plugged a catalytic muffler and Cummins warrantied that. This is for all Cummins engines, not just mechanical engines. I think I have a digital copy of the service bulletin from Cummins if you'd like it. Besides, the engine in the Liberty is built by an Italian company that is a subsidiary of Detroit Diesel which is owned by Daimler and has absolutely no ties with Cummins that I am aware of.

All oils, whether they are synthetic or not, will burn. It is just as matter of what temperature is necessary to make an oil burn. The combustion temperatures on a diesel are quite high and most oil will burn just fine. In fact, a CAT at work with a synthetic test oil burn the oil so well it lifted the head when it started burning engine oil that was mixed with intake air from a bad turbo oil seal. Keep the mixture rate of used oil with the fuel will help ensure that you get a good burn. Your point about high flash point should be remembered though, I still recommend that if you want to burn waste oil with your diesel that you make sure to put a good load on the engine and run it at full load every so often to keep the injector tips, etc. free of carbon build up.

Reg# 43897, are you sure you don't have a DPF on your Liberty? I was under the impression that they had DPF but no catalyst. At any rate, I would mix the oil with regards to fuel system considerations discussed above.
 
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sdeeter, that is why I recommended a bypass filter like the MG as it is submicronic, that is, less than 1 micron. A 10 micron oil filter (which is probably 10 microns nominal) is about the same as a good full flow engine oil filter. A MG, Frantz, etc. will work much better in this application.

Cummins does not state, but RECOMENDS blends up to 5% biodiesel. They do not impose limits and they do allow 100 biodiesel. The only liability is if you have a failure directly related to biodeisel it MAY not be covered under warranty. I know of a guy who was running 100% bio and plugged a catalytic muffler and Cummins warrantied that. This is for all Cummins engines, not just mechanical engines. I think I have a digital copy of the service bulletin from Cummins if you'd like it. Besides, the engine in the Liberty is built by an Italian company that is a subsidiary of Detroit Diesel which is owned by Daimler and has absolutely no ties with Cummins that I am aware of.

All oils, whether they are synthetic or not, will burn. It is just as matter of what temperature is necessary to make an oil burn. The combustion temperatures on a diesel are quite high and most oil will burn just fine. In fact, a CAT at work with a synthetic test oil burn the oil so well it lifted the head when it started burning engine oil that was mixed with intake air from a bad turbo oil seal. Keep the mixture rate of used oil with the fuel will help ensure that you get a good burn. Your point about high flash point should be remembered though, I still recommend that if you want to burn waste oil with your diesel that you make sure to put a good load on the engine and run it at full load every so often to keep the injector tips, etc. free of carbon build up.



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I know that guys have had issues burning synthetic oils in their CTD trucks at TDR...a high grade synthetic may not burn in our environment...and they reported the oil literally dripping from the exhaust pipe when they ran syntheics through as fuel.

As for the bypass filter...yep, I have one, but not everyone does...so you got to remember THOSE people are also reading this thread...and then you also got to have a completely sterile drain pan and drain environment as to not introduce dirt into your waste motor oil...not everyone is as particular as some of us...

WMO = waste motor oil last I knew...where did the biodiesel come into the picture??? You sort of lost me there... Cummins only recommended 5% waste motor oil in fuel the last I knew...even their centinal system was only a 5% blend...

steved
 
No trap in it but it does have a catalytic converter. Doing a gravity-feed filtration of the used oil currently. Will not be burning much of it at any given time. Perhaps a couple of litres per full fuel tank.

John.
 
Running synthethic motor oil in my fuel (93 Cummins) cut my fuel economy and performane significantly, even in very small amounts. The same engine tolerates dino motor oil up to one quart per tank. Too much will hinder economy and performance. Your engine might be different.

Jim
 
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