Burning old motor oil in the fuel? Anyone doing this?

[greggearhead]

Just curious, as the bigger diesel trucks do it, and it was a topic on the Cummins forum, etc.  

Basically, take used oil and filter it, then pour a percentage into the diesel - like 5-10%.

[Master ACiD]

ive tried it and ran into some problems. the biggest problem is that motor oil doesnt burn as completely as diesel and tends to blow past the rings.

i was runnin 5-10% oil in my fuel and i was having to DRAIN out a  quart of extra oil that accumulated in the sump every week or 2.

what this tells me is that a significant ammount of the oil isnt being burned but is being blown between the rings and deposited back in the sump. this may be OK for an oil burner or a big rig which uses oil (to help keep the oil level up), but it isnt worth it on a nice tight motor. espically sence its dragging fuel particles down into the sump with it. so its adding fuel dillution problems.

if alot of the oil is being deposited back into the motor, then its not bring burned as a fuel and hence isnt providing any benefit. therefore i stopped doing it and sence then my engine oil levels have remained at normal.


just for the hell of it i tried it in my gas car one time and got the same problem. the oil was getting past the rings and making the oil level in the sump go up.

[RabbitJockey]

i bet it's hellish good for the injector pump.

[LeeG]

yeah, I thought about doing this and was worried about the long term affects on the IP.

So now I just leave it in the sump to burn it!  :roll:

I never would have expected the oil to seperate out in combustion like is described by Master ACiD.

[greggearhead]

Gotcha - good information.  Thanks.

[hillfolk'r]

ive done it to get me home in the middle of nowhere, well i looked in the trunk for a "gas can"+ i had a gallon of waste oil for some reason,i dumped it in the tank
i wasnt totally out of fuel,it started to sputter thru a corner,so i shut it off before i lost the prime,ya need a little diesel to mix it up at least
it ran ok but i didnt wanna rev it much,it felt starved much above 3k rpms,so i put put'ed to the station  just fine
ive also been low on fuel and gone in a station with no diesel,so as not to take a chance+run out of fuel before getting to another station,ill buy like 3 cans of atf+dump em in,think about it,1 qt will take you approx 10 miles(40mpg)
ive not done this in my tdi-m,but ive done it in a few idi's...

[HP]

What I've heard is a mix with diesel and a small portion of 2 stroke motor oil  :idea:
To clean up the injection system?!

[greggearhead]

Yep - the Cummins guys swear by 2 stroke oil.  Quieter and more mileage apparently.

[Justin]

i have done it in up to 20%, ran fine, i have no easy place to dispose of it with out burning it in an open pit (which i dont do because i would feel bad about it) or in my car and i feel that there is a more complete combustion in the car, I do filter it 10 micron then 2 micron, not that i would do this but since it turns your fuel Black, even with a small percentage you could probably run the untaxed fuel and cover up the die with used motor oil

I have also ran 10% used ATF since i cant get rid of the stuff easily, nock on wood everything has worked for me like that as well as used cooking oil in the heated tank for over 25 k miles of vw diesels

later
Justin

[MacGyver]

If anyone else reads Farm Show Magazine www.farmshow.com many guys in there have wrote about doing it to get rid of used oil, and for extra 'free' fuel. General consensus is up to ~15% mix, above that may increase cylinder deposits.
Though I've never done it yet, I'd personally be inclined to try it in an indirect engine due to the simpler pintle injector design.
Plus filter it FINE as Justin mentions.

A good friend that lives close by runs all manner of mixed crap through his poor old VW, gas/diesel/WO/WVO mix, roughly checked for viscosity & ignition point...and has done so for years & hundreds of thousands of km's.
He never seems to have any IP troubles, or unscheduled engine problems of any kind, so I know they'll take a LOT of abnormal abuse :shock:

[745 turbogreasel]

...unscheduled engine problems...

Any tips as to how I might go about scheduling my engine problems? :lol:

[MacGyver]

Hmm, how about 'unscheduled engine maintenance'...?

My post didn't even live 24hrs without open ridicule

Smartass :lol:

[glichter1]

I used to run 100 percent used motor and tranny oil for about 2 years, ehating it up like veggie oil, especially tranny oil was good, ran smoother and quieter, same power no more visible smoke did have problems with injector coking took them apart every 4 months, the rings became progressively more sticky due to deposits of lots of unburnt oil soot, then got me a turbo motor and after more reading on the subject decided its not worth it on a tight motor, my best friend did this for many years in germany now replacing rings at 800000 km, not bad.

[clbanman]

A co-worker has been mixing motor oil (unknown ratio mix of 15W-40 and 10W) that we discard at work in a mix of 2/3 oil, 1/3 diesel fuel for close to a year with no noticeable problems according to him.  (Note, he does reduce to about 1/3 oil, 2/3 diesel during the winter.)

[AdAm84]

I recently dumped about 4 quarts of used synthetic (amsoil)in my n/a rabbit. It was from a stationary natual gas generator that runs like an hour a week. the oil is changed evry year and always looks super clean.  This rabbit ran good prior, but runs hellish now :evil: It will break the tire loose from a stand still. I'm gonna assume that it was the high detergent qualities of this oil that cleaned the injectors and pump. No word on milage gains yet. but i recommend it so far :lol: