Burning used engine oil as fuel...

[Gary - K7GLD]

Just a quick FYI on burning waste oil. Immediately after pouring about a gallon of recently drained used Delo 400 15/40 into my main fuel tank, my lift pump pressure became very erratic, frequently not pumping any fuel at all - thank God for the pusher being in there to take up the slack!



Indications are that the stock LP is cavitating with the added used oil - pressure quickly returns to normal if I really hit the throttle under load, and the output of the pusher pump causes the LP to regain normal function.



The Carter pusher thus far seems unaffected, possibly due to it's lower operating pressure. I've changed the inline Frantz TP cartridge, and noted it was quite dark with the accumulated soot contained in the used oil - but normal LP function was not improved upon changing to a new TP cartridge.



Upon topping of the tank with about 10 gallons of fresh undiluted fuel, LP function is greatly improved - my particular LP just doesn't much appreciate the use of used engine oil mixed with diesel fuel - might not have been as severe if I hadn't used a 30 to 1 mix ratio...



Just keep this in mind if you have a similar plan on your horizon - and this sorta makes me wonder what might happen in relatively high doses of various bio fuels...



YMMV!

 

[mberry]

Thanks for the info Gary. I appreciate it.

 

[Doubleclutch]

Not tossing harpoons, but why do you want to burn dead crankcase oil in your truck? Is it a way to get rid of the Hazmat? Honest question.

Greg

 

[mberry]

Greg,



Others will answer more precisely, but I believe it adds lubricity to the fuel. It doesn't seem to work as well with synthetics since the synthetics don't burn well.

 

[Tim]

It gets rid of it and it's free fuel.

 

[RLutkenhaus]

Why would you want to do something like this? The difference in viscosity between oil and diesel is so drastically different, and the pumps are not designed to operate as such. Not to mention that the increased emmisions and soot will eventually clog the catalytic converter, increase carbon deposits on the injectors, valves and pistons. You can dispose of used oil just about anywhere for free. They recycle the stuff, and turn it in to other usable products. I'm not a tree hugger, but what you are doing in my opinion is not something the engine is designed for, nor is it good for the environment. If you want to reduce any wear by adding stuff to your fuel, use power service or two-cycle engine oil, and use fuel filters that filter down to the 2 - 5 microns or whatever the smallest rating is.



Robert

 

[Pmaloney]

Robert, actually in correct doses used engine oil is perfectly OK and it is free fuel. Cummins sells a kit (I believe it is marketed for OTR trucks) that burns some used oil while replacing with new. Someone correct me if I'm wrong here.

 

[Grizzly]

It gets rid of it and it's free fuel.

Tim, some people know very little about anything. It is better for people like that to keep their mouth shut and their ears open so that they can learn something. Grizzly

 

[tae73]

Robert, actually in correct doses used engine oil is perfectly OK and it is free fuel. Cummins sells a kit (I believe it is marketed for OTR trucks) that burns some used oil while replacing with new. Someone correct me if I'm wrong here.

Here is the comments from the cummins website, I dont know it would be good for ours with the common rail. This is a first of ever hearing about burning used oil.



http://www.cummins-sp.com/engines/parts_accessories/centinel_system.htm



CENTINEL™ System

As duty-cycle-dependent intervals, CENTINEL removes a small amount of used oil and sends it to your fuel tank. The used oil blends with the fuel and is burned during combustion. Simultaneously, CENTINEL adds the same amount of new oil from a makeup tank into you engine. This constantly replenishes oil additives, improving oil quality over the life of your engine. With the required Fleetguard ES System oil and fuel filters, the heavy-duty automotive oil change interval extends to 525,000 miles, with oil filter change intervals at 100, 000 miles. In High-horsepower industrial applications, the oil change interval is 4,000 hours and the oil change interval is 1,000 hours, minimizing waste-handeling and disposal costs.

 

[Gary - K7GLD]

Diesel engines CAN run on a wide variety of fuel oils - sure, varying degrees of lost combustion efficiency will occur, depending on what is being used, but kerosene, diesel #1 and #2, jet fuels, and various bio fuels as well as used deep fryer oils are being used... Those with catalytic converters might have a concern, but MOST Cummins engines from '89 to present day (including mine!) don't HAVE cats, so no worries there either for most.



I use a SUB-micronic Frantz fuel filter, so used oil contaminents aren't a particular concern - my used oil is VERY clean. And the Cummins has NO complaints with the used lube oil, only the LP is somewhat disturbed.



Still, something about the added used engine oil has caused my stock LP to cavitate - possibly too high a percentage of used oil - so I'll first try substantially reducing that percentage, and if problems persist, I'll just not use it at all.



And yeah, 3 gallons of used oil is worth about $7. 50 at current local prices for diesel, so I'd rather burn it as fuel if I can, rather that simply give it away...

 

[Doubleclutch]

Well now, I can see that in the case where an OTR truck is running long hours/miles between shutdown/cooldowns, the bleed and feed of oil maintains crancase oil additive package in spec. Thanks for adding that tae73! Makes sense. But thats not for fuel lubricity. Also, that's not a "batch" process. Warm oil is added in a small stream to a warm tank that is recirculating while driving down the road. I know Gary has taken precautions to protect his pump and injectors by adding filtration, but I think he lives live fuller than I. I'm guessing there are more "cats" out there than he estimated as well.

Greg

 

[Gary - K7GLD]

" Makes sense. But thats not for fuel lubricity. Also, that's not a "batch" process. Warm oil is added in a small stream to a warm tank that is recirculating while driving down the road. "



Probably even more significant, is I suspect the 18-wheeler engines aren't using the LP setups WE are "blessed" with - so fewer concerns in that area. As I said, the Cummins is running just peachy, and I have no reason to suspect the VP-44 is having any problems, but I sure hate the design of these Carter LP and pusher pumps, and simply can't understand the need or logic in actually diverting fuel flow thru the pump moter itself!



I don't think that is a factor in my small problem, but the constant shedding of motor wear particles, brushes, bearings and such, into the fuel flow going to the VP-44 is NOT a good thing, nor is trusting in the stock fuel filter to successfully catch 100% of those shed particles before they reach the VP-44!



As far as I am concerned, an open type pump motor, similar to the ones used in our heater A/C blowers and windshield wipers, with replaceable brushes would be FAR preferable, and SHOULD still be far less expensive than some of the other alternative systems used by some owners here.

 

[Snoxracer]

To each is their own, but I know that I change my oil for a reason, to get the dirt and contaminants out of my motor so why would I want to put them back in the motor via the fuel? They make additives for pump lube and fuel system conditioners. Just my thoughts.

 

[Gary - K7GLD]

To each is their own, but I know that I change my oil for a reason, to get the dirt and contaminants out of my motor so why would I want to put them back in the motor via the fuel? They make additives for pump lube and fuel system conditioners. Just my thoughts.

I will absolutely, flat out GUARANTEE you there are FAR more nasties floating around in the fuel stream shed from these Carters than there are in my lube oil stream.



I have NUMEROUS times had occasion to carefully inspect accumulated residue on the top surface of my old TP filters removed from my Frantz bypass and fuel filters - NO comparison - the fuel filter is absolutely COVERED with microscopic metallic bits and pieces from the LP - and NONE, zip, zero, nada, to be seen on the bypass oil filter.



That, combined with the frequent excellent oil analysis reports I get back from the labs causes me NO concern as to engine or VP-44 issues - but that LP is a different story...



But like lots of other choices in life, to each his own!

 

[EBottema]

It is perfectly okay to run used engine oil in the engine... I would run it through a filter first though to get out any large particles. I would say it would be less chance of any clogging problems in a 1st or 2nd gen engine since all the tolerances are less than the 3rd gen engines. As for emissions, wouldnt it just be better to use the old oil for something useful than waste your time using more energy to recycle it back to new oil? And second, who cares about soot and cats, we don't run cats around here

 

[MMeacham]

Question...???/

I have been using a qaurt of transmission fluid in every fill up. I put about 10,000 miles a month on my truck. It helps lubricate and cleans injectors... plus cheaper than Howes!!! Anybody else do this... .

 

[Joseph Donnelly]

transmission fluid is not designed to burn and has friction modifiers in it which aren't good for the pump. For that matter, why did you change engine oil? Wear metals, acids, soot, etc. in it, right? So why send that crap through the injection pump which relies on clearances in the millionths of an inch?

 

[Vaughn MacKenzie]

I think MMeacham is implying new ATF, but I agree ATF isn't what you want in your fuel due to the friction modifiers. Better to use lube oil.

I will absolutely, flat out GUARANTEE you there are FAR more nasties floating around in the fuel stream shed from these Carters than there are in my lube oil stream.

I would tend to agree with you on that, and I would venture oil lube oil that's settled for a couple weeks and run through even a crude filter has less abrasive contaminants than what comes from your fuel nozzle.



Vaughn

 

[Cryotek]

FWIW- My company fleet of OTR trucks uses the Centinal system. It is a great idea for someone elses trucks. We have alot of problems with clogged fuel filters and fuel flow problems in the winter. The system is very hard on the injectors also.



These are not my opinions just facts of running a fleet of OTR semis with the Centinal system. If my mechanic had his way he would take'em all off, but the company won't let him. THese engines are designed to use clean fuel not dirty fuel. Hope this helps.

 

[robert4570]

Gary ,

Is there a reason why new clean motor oil isn't used instead old oil ?



Thanks

Robert