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Burn Used Motor Oil?

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bobk

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  1. OWNER - I own a Hatteras Yacht
Hatteras Model
48' MOTOR YACHT-Series I (1981 - 1984)
I just hauled 15 gallons of old oil to a garage for recycling. I keep thinking we ought to be able to mix it into the fuel to recover the $4+/gallon. Is any one doing that? These old DD's use low ash oil, so maybe it's OK??????

Bob
Chateau de Mer
6V92 425 HP
 
is it really worth screwing up your engine in the long run? 15 gallons of diesel @4.50 gallon is only 67.50...... the engine is designed to run on diesel, not used motor oil. how much is a tune up? an injector? maybe an overhaul? is it really worth it? so you took it out of the crank case because it was old and dirty, and now you want to put it in the fuel system........
 
And probably got acid in it as well, real good lubricant !!!!
 
You change oil because in doing it's job, it accumulates the acids, minute metal particles and numerous other contaminates engines develop while running. To run them through your fuel system just doesn't make any sense.
Will
 
I used to do it here on the ships but I would run it through a centrifuge first. I would blend in 1 oil change (165gals 1 engine) into a 4500 gal diesel settling tank which would slowly go to the day tank which holds another 4500 gals of diesel. The settling tank would be diluted again in the course of the next 12 hours with another 2000 gals as we burned it off so that comes out to a very small % of blend and it really screwed me.

After several injector problems on the 3512 cat gen sets, one of which let to a runaway engine and wiped the crank I don't bother with that anymore and don't recommend it.

Geo
 
Detroit specifically condemns this practice in their shop manual. Why bother?
 
No problem
 

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Bob,

I agree with the others and would not do it.. I save mine for a friend who burns it in a special furnace in one of his buildings to produce heat and hot water. Even then he has some costs with filters etc...

Walt
 
For what it is worth Detroit Diesel, Cummins and Cat all have allowed this in the past with out any warranty issues. Cat and Cummins make an engine that burns its own motor oil by desgin, it has a make up tank to replace the oil delivered to the fuel tank. thoes engine never require an oil change.

A fleet I work with has one, a Cummins N14, in service for 6.5 years. So far it is doing a good job, with a small reduction in maintenance cost.

JM.
 
I agree it's not worth the risk, but the math is flawed...I don't know anyone that pays $4.50/gallon for motor oil. More like $16.00/gallon. Splain that one to me Lucy!
 
The math is right. its based on the cost of fuel it's replacing as the oll has already done its job as a lubricant.

By the way Can I sell you some oil? $16/ gallon?

Thats worst moron prices isn't it?
 
I'll chaulk my last post up to lack of sleep and dealing with some adult kid issues....
Wish I could say I've been drinking, but haven't had a drop in 24 hours....
 
Years ago it was pretty common to burn used motor oil in DDs. I worked for one of the largest companies in the world that did it as normal operation - this was in the '60's. I can't say scientifically whether it had any ill affect on the engines but given the use involved, my OPINION is that if it did it was not significant. OTHO, these engines were in use and running every day so maybe that would mitigate any adverse affect.

However, as noted, the most recent DD 71 series service manual states it should not be done. I can't say about earlier versions. It would be interesting to look at a manual from that era ('60s) and see if there is any mention of it either way.

"Wish I could say I've been drinking, but haven't had a drop in 24 hours...." Wow, that's impressive; I don't think I've gone that long except when I was in Vietnam or in the hospital! Good work! :)
 
Last edited:
Thanks guys. I guess I got the expected answer.

BTW (that's by the way for us old guys), I haven't had a drink in more than a month. Wish I could say I felt different or something works better, but nada. Two more months to go on the NA trial. BTW2, there are a couple of half way decent NA beers out there, but not the original O'Douls! Now if I could find a reasonable NA wine.....

Bob
1981 48MY
Chateau de Mer
 
All technical arguments aside, as my old gambler grandad used to say..."That juice just aint worth the squeeze."
 
I sent an email to an old OLD friend of mine who was a Tank Battalion maint tech (WO4) with the 2nd armored Div at Ft Hood circa 1970. I asked him if he remembered anything re mixing used eng oil with fuel for DD engines. He said the guidance at that time was that it was fine to mix it "up to 50/50" with fuel. He said that used engine oil from oil changes was never "disposed of," just mixed with the fuel.

He said that 50/50 figure was in the US Army tech manual for the 71 series engines. He has no idea what may have been in the actual DD manual in that era because he never saw one.

NOTE: I am NOT suggesting anyone adopt this procedure but I thought it was interesting and I definitely recall the procedure he described.
 
That's why them engines never wore out, they ran mostly on oil..or close to it...very little wear...LOL...
 
Laval used to make a device that was intended for this; it filtered the waste lube oil and added it to the fuel tanks a little at a time. It cost quite a bit, though, and by the time you've purchased it and installed it, I don't think you'd save anything. Quite the reverse.

A lot of garages heat using waste motor oil, but the burners are designed to burn waste motor oil, and the burner jet is quite a bit bigger than a diesel injector.

I don't think I'd do this, even with old Detroits. With modern CR engines, I would never do it.
 

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