Black diesel anyone??

scr8pdo

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Sep 9, 2011
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Audi A4 B5 1.9 TDi AFN
As the title says, has anyone tried black diesel AKA old engine oil blended and filtered?

I have been looking into this as an option as I have virtually unlimited access to this stuff as in a breakers yard, and have heard so many different opinions on this subject:

For a start, there has been talk of there being metallic particles in the oil, but surely some of the filtering techniques would surely sort this problem, some people are saying a definate NO NO and others are saying its fine as long as you do this or that, others say they would use in an older diesel but not in a common rail etc etc etc.

I will tell you here and now my very little experience with it, I was using an old car last year that had a few weeks tax and test left on it and the car was due to be scrapped at the end anyway, it was an old R reg Citroen Xantia TD btw, I was also running it on the very least fuel I could get away with as I didnt want to be spending any money I didnt need to before I ran it in, well me and my mrs were driving round Wigan when it coughed to a halt out of fuel, I checked the boot for a jerry can to go and get a gallon of diesel and all I had was a 5 litre Castrol GTX bottle full of used filthy black engine oil I had drained from my Iveco recovery truck, I thought what the hell and poured it straight into the tank, I connected my booster pack up, primed the filter bulb up until I was getting fuel out and spun it over, it fired into life no problem whatsoever.

Now I wouldnt condone doing this on a car you were planning on keeping, remember this was filthy black sludgy old engine oil with a good 12k on it if not more, but it DID run and ran very very well, BUT I dont rekon the fuel filter would last too long running stuff that dirty through it.

Now I have heard of sooo many different filtering, blending methods being used from tying a knot in a leg of denim jeans and letting the old stuff filter through, then other methods of mixing it 50/50 with road fuel then filtering through different micron filters down to 1 micron or 0.5 micron, then at the other end of the scale using a proper centrifuge to do it.

Now all I would be concerned about is how much filtering would need to be done, I would have no problem going out now and tipping a gallon of new Castrol GTX in my tank cause I KNOW IT DOES WORK, its just as I say how far to go with the filtering and or blending, obviously when I did it it was only for a very short period but I would be very interested to hear from folks who have been using "Black diesel" as it seems a very good way of saving money plus recycling the old oil, win win if it works fine

PS: there was one other way I heard of filtering but it would take a heck of a long time:

have a bucket of WEO (waste engine oil) raised on a shelf with an empty clean bucket below, then cut a length of rope measured from the bottom of the top bucket of WEO up and over the edge and down into the new clean bucket, looped over, the idea being the rope would absorb the oil over time and sort of syphon down into the clean bucket, while the rope would act as a good filter and would not allow any suspended particles to get into the clean one :)


BTW: my car is not a PD or common rail and I would be very reluctant to put it in a common rail until I knew it was safe or had tried it on an old scrapper, I also hold no responsibility for any damage if anyone tries this ITS UP TO YOU, I was just telling you of my personal experience and the car was running absolutely fine when I scrapped it a few weeks later, in fact it seemed to run smoother on the old oil :)
 
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Ski in NC

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I have run a 50/50 blend of diesel and used engine oil in a IDI genset. After a while the piston rings stuck from deposits, blowby shot out the dipstick and engine shut down on low oil pressure.

The problem was there are numerous compounds in lube oil that do not burn completely and will form deposits in various places. Some of these compounds might be extracted by filtration, some may be submicron and pass through any reasonable filter.
 

scr8pdo

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Sep 9, 2011
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Manchester
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Audi A4 B5 1.9 TDi AFN
I have run a 50/50 blend of diesel and used engine oil in a IDI genset. After a while the piston rings stuck from deposits, blowby shot out the dipstick and engine shut down on low oil pressure.

The problem was there are numerous compounds in lube oil that do not burn completely and will form deposits in various places. Some of these compounds might be extracted by filtration, some may be submicron and pass through any reasonable filter.
Thanks for the reply, this the feedback iam interested in as I dont want to trash a good engine to save a few quid, there is a LOT of it on the net with so many different stories with WMO/WEO

As for WVO or SVO I have used unlimited amounts of SVO for a long time in various cars with no problem at all iam talking years with that stuff, it seems a shame if WEO could have been used safely as I have disposed of tons of this.

I might even get a "project car" or just an engine running in an old shell and just feed it generally filtered WEO and see how long it would run, just keep it in the corner of the yard and burn the old engine oil through it???
 

b4black

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IL
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1998 Jetta blue
The problem with WMO is its very high boiling point. Diesel fuel tops out at about 650°F, while WMO is well above that. The high boiling point molecules are what makes the deposits.

A genset is not a good indication of the practicality of WMO in a vehicle. They run at a constant (low) rpm. A diesel engine revs higher at times. The high rpms produce high temps which will help remove the deposits. In other words, the nature of a genset is much more deposit-prone than an engine in a vehicle.

SVO or WVO is very different than WMO. Both are viscous, which can be dealt with be diluting or heating. WMO is very stable, but WVO is very unstable and easily oxidizes. This is why "grease car" kits purge the system with diesel before shutting down. WMO users don't do this.

I would be more fearful of SVO than WMO. I run dilute WMO in my truck without any concern. I would not run SVO/WVO.

 

scr8pdo

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The problem with WMO is its very high boiling point. Diesel fuel tops out at about 650°F, while WMO is well above that. The high boiling point molecules are what makes the deposits.

A genset is not a good indication of the practicality of WMO in a vehicle. They run at a constant (low) rpm. A diesel engine revs higher at times. The high rpms produce high temps which will help remove the deposits. In other words, the nature of a genset is much more deposit-prone than an engine in a vehicle.

SVO or WVO is very different than WMO. Both are viscous, which can be dealt with be diluting or heating. WMO is very stable, but WVO is very unstable and easily oxidizes. This is why "grease car" kits purge the system with diesel before shutting down. WMO users don't do this.

I would be more fearful of SVO than WMO. I run dilute WMO in my truck without any concern. I would not run SVO/WVO.


This is excellent feedback, so you yourself would rather run WMO than SVO? Now that is interesting and what you say does make sense about the stability, I am no petrochemist but I can understand a decent motor oil remaining more stable through a heat range etc than a fuel or veg oil so it protects and gives the same performance durability as a lubricant.

As I have said I know this definitely does work its just the long term effects it has on an engine I would be concerned with, eg. I would run a car that I knew I was gonna scrap at the end of the month on WMO after my first experience without hesitation but would be wary using it on a car I wanted to keep or care about, until I had proved there were no adverse effects.

Another thing I did a while back:

My uncle had heard that I was experimenting with WVO, he bought 7, 20 litre cans of WVO he had acquired from a local indian restaurant which he had planned to convert into biodiesel but didnt have the time, he asked me if I had wanted them before getting rid, to which I aid "YES PLEASE"!

Anyway, this stuff was raw unfiltered junk that had sat in a the rear yard of a restaurant for a while, it had white conjealed fat on top and a bit of water mixed in, it was rank stuff, cloudy brown with bits etc, I at the time was running an old Laguna 2.2 TD which was also on its last legs, and in a mad moment emptied 40 litres of this crud straight into the tank for a laugh. The car ran fine for miles and miles, it absolutely reeked like a BBQ but it worked all the same, then it started playing up, hard to start, smoke etc, then it wouldnt start at all, I had a spare diesel filter, so whipped the old one off and found it full of white gunk, I shook the old filter out and just tried it back on, Voila! It ran again for another 2 weeks.

What Iam saying is that if I had just changed the filter over it would have lasted for a good while, if I had filtered the junk in the first place I would of had to change the filter anyway, and apart from the smell out the back, the car ran even smoother and quieter on wvo than road fuel and was no different.

If I was going to put WVO in a car I would give it a good filtering and thats about it, I wouldnt personally sod about with caustic soda etc trying to make pure clean bio, I would rather buy a pack of 10 fuel filters trade from a local trader and change as and when needed as surley, surely the fuel filter would strain any damaging particles whether fat, metal or fag ends from your chosen brew?????

BTW: As I stated I have used SVO straight off the shelf many times when its been cheaper than road fuel and it works fine as far as iam concerned, it seems though in the last few years the supermarkets have got wise to this and the price of cheap veg oil has gone up, but when I find it cheaper I ALWAYS buy it, the only downside, if it is one is that your car smells like a doughnut fryer LOL
 
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Lug_Nut

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At 1.42 pounds for a liter for DERV you are currently at the equivalent of $8.70 per US gallon, but even at, that I think 'free' used motor oil is too expensive for use as fuel.
 

sonic reducer

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1997 passat tdi
At 1.42 pounds for a liter for DERV you are currently at the equivalent of $8.70 per US gallon, but even at, that I think 'free' used motor oil is too expensive for use as fuel.
please explain this statement?
I have no experience with WMO(or wvo for that matter) but I can get ahold of a lot of wmo from a friends shop and I'd like to run it in my 6.9 idi ford. maybe my b4 passat too but seems more risky and the payout is a lot lower.
 

Spdmini

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please explain this statement?
I have no experience with WMO(or wvo for that matter) but I can get ahold of a lot of wmo from a friends shop and I'd like to run it in my 6.9 idi ford. maybe my b4 passat too but seems more risky and the payout is a lot lower.
DERV = Diesel Engine Road Vehicle. In many places fuel is purchased per liter, so GBP 1.42 per liter come out to USD 8.70. Using waste motor oil as fuel is a poor economic choice. While the oil is free, the damage to the engine would outweigh the money saved by running wmo. Typical Cost/Benefit analysis.
 

Ski in NC

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The economics can support this in the UK. At 8 bucks a gallon, you can burn like $9000 in fuel in 50k miles. If the engine lives 50k miles on 50/50 wmo/diesel blend, you saved $4500. Enough to buy a couple engines from a breaker. We just don't know how long a tdi will live on various blends. It could be as simple as cleaning deposits off injectors periodically, and maybe popping pistons out and cleaning above top ring groove. Turbo might gunk up on hot side too.

I'd say get a spare engine set aside, then try it. It could be the tdi will live just fine. Worst case a couple days to swap out motor. Best case $4500 in pocket.

Maybe find an old centrifuge from a ship breaker. Or make a filter rig that spins warmed oil through series of filters, last one being maybe 2mic.

I looked at distillation rigs, but those look either dangerous, complicated, expensive, needing full time operator or a combination of any of the above. Really not practical unless doing it on an industrial scale.
 

MikeMars

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... Enough to buy a couple engines from a breaker. ...
Or even enough to buy a running junker from eBay or car auction. Around £ 500-ish for a high mileage 10 to 12 year old VW or Skoda 1.9TDI with a recent MOT (annual safety/emissions test). Scrap it when the next MOT comes around if it needs too much work, and get another.
 

shanate

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I'm curious to know how this turned out. How have 1.9 PD engines done on running used filtered engine oil as fuel?
 

Nevada_TDI

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I have seen the results of many different types of filtering/cleaning wmo and the centrifuge method seemed to get out particles than even a fine filter would not catch. There are many acid based compounds found in wmo and neutralizing them before using wmo as a fuel should be considered. I have read of guys that run wvo and and circulate baking soda in warmed oil to neutralize the fatty acids that create the concrete-like deposits in cylinders; I don't know if wmo would need such a treatment unless the wmo came from gasoline engines primarily.
 

[486]

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I run it in a ford IDI but not in my TDI

TDIs have very picky smoke maps and idle limits, they don't run very well on waste oil fuel for much the same reason as they don't run well on gasoline. The cetane is so low that you need to put in a crapload more fuel to get the same power with the same timing, electronic governors don't do this as they think you're loading down the engine in a very harsh way so they're programmed to stall out. Mechanical governors just happily chug along putting in the extra fuel.

Toss some big nasty injectors in it without a tune (or better, a tune set up for more timing advance but still the stock injectors) and it'll probably work a lot better.
 

BKmetz

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maybe my b4 Passat too but seems more risky and the payout is a lot lower.
Don't use anything but D2 in your B4. Even though the 1Z engine is the first generation TDI and is quite crude by today's technology, it can't handle WMO at all without severe damage. It can't really handle SVO or WVO either for that matter.

I put over 750k miles on my 2 B4s. In all those miles I only had to replace injectors in one car once at around ~300k miles, and a temperature sensor in the other at around ~300k miles.

Here is a photo I took of the inside of the fuel pump when I replaced the temperature sensor. This photo was taken in the parking lot at the 2006 Philly TDIFest. JasonTDI & I replaced the temp sensor. You can see the paper towels stuffed around the fuel pump to catch the spillage when we pulled the top off. If you use pump fuel and change your fuel filters when you're suppose to, this is what the fuel pump should always look like inside.


This is what the temperature sensor looks like.


:)
 
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[486]

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With the sickly stink of vegetable oil coming from the pumps now that they've mandated biodiesel blending is making me think again on this. My #3 injector leaks a little externally, and the front of my engine looks like a neglected deep-fryer as a result. I'd do this to just get back to a proper petroleum based fuel.

Still running W85 in my ford, still showing good results there, and the tuning side of things is rather easy for me to bumble through. Just leery on possibly messing up my $400 set of nozzles... Though putting it that way makes it seem silly, as that's only 10 fillups or 6000 miles of driving.

May well be some development in this on my end. 12mm/de110 pump and DSS .360s should give enough fuel to compensate for the lower energy density.
 

[486]

Top Post Dawg
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right now I'm at about 3 gal used lube oil, 1 g gasoline and 6 g diesel

Been running over-advanced timing, so it was very sluggish with proper diesel, but with the worse cetane of the waste oil the turbos seem to be lighting up a little earlier, almost as they were with the previous well-retarded timing and proper diesel. Gonna continue messing around with this, got a bucket that's premixed 4g of used ATF and 1g of gasoline that was destined for my truck which is parked for the winter, that'll be going in next when there's room, and the temperature's going to be down real low all next week so that'll be a good test for the starting side of things.
 

WarmStart

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TDI
When I had 1.6 IDI I run some time 50:50 diesel hydraulic oil. It had more power in low revs. But it wear out my injector pump. I didn't purify oil in any way.

Here are some ideas how to purify WMO:
https://sciencing.com/distill-motor-oil-diesel-fuel-7861173.html
https://usfiltermaxx.com/en/content/9-make-black-diesel
https://www.youtube.com/watch?v=zFNnoQyN7Zs
Few years ago there was much more info about black diesel.

If I would run it now I would use settling tanks and centrifuges to purify it.
 

[486]

Top Post Dawg
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Multiple days parked outside in -20 to -30F
Started every morning.
Diesel sucks, lube oil and gasoline is where it's at!
 

[486]

Top Post Dawg
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5w20 drain oil, alh with big honkin fuel system stuff and reasonably sized turbos
 

Pat Dolan

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diesel WMO is black because it contains soot. Yes, you could be getting some deposits from the higher boiling point of the longer paraffin chains of vacuum distillates (lube oil base stock), but IMHO the big deal is that you will be gluing a lot of pure carbon (soot) into those deposits. Also, the additive package contains a lot of metallic compounds (especially zinc) that will make yet another deposit that the engine might no be so crazy about. You can not filter or centrifuge either of those out, just the big stuff.

I have run a lot of gensets on napthenic base stocks that are about 5 CSt @ 20C, and the ultimate limit seems to be carbon accumulation in exhaust side. Seem to scavenge well in combustion chamber. However, we have some very electronic engines on the farm that really do NOT like running anything but ULSD, so there are some definite limits to alternative fuels. BUT: that is no endorsement of WMO. I would want to see someone run a well known mix for many miles in any particular (all mechanical) engine and see a teardown for deposit characteristics before trying it in the very same engine (may 486's Ford/IHC IDI could be a test mule).

Of course, for literally junkyard engines, what have you got to loose? .... just as long as you tear down and report to us.
 

[486]

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I would want to see someone run a well known mix for many miles in any particular (all mechanical) engine and see a teardown for deposit characteristics before trying it in the very same engine (may 486's Ford/IHC IDI could be a test mule).

Of course, for literally junkyard engines, what have you got to loose? .... just as long as you tear down and report to us.
rofl
motor that came with the $650 truck (at about 250k miles) got pulled out about 4 years and 2k miles later, it had been bubbling out the rad pretty good for the entire time I owned it, assumed it was head gasket. Cylinder wall was eaten through as these do. All 8 were sleeved and it was the worst rebuild I'd ever seen with the main bores beat like it'd been slung around with a chain through them. The problem cylinder had rust pitting in it so bad it's a wonder the piston rings hadn't caught on it.

The motor I put in, (a $600 craigslist deal) also seems to push coolant. It also hydrolocks itself if it stops at the right spot. rofl
I've given up on 7.3s, I'm halfway looking for a 6.9 as they don't have cylinder wall issues, but they're all long scrapped around here.

So yeah, your "literally junkyard engines" quip is understating the garbage that I drive. c:

ETA: oh right, on the buildup in the exhaust, is it coke?
I'd bet that would be more a problem on constant load stuff than an automotive engine where it can see periodic loading well beyond what you'd see on an industrial engine. My TDI sees the pyro pegged pretty often, and the truck is naturally aspirated (but showed no signs of any buildup in the exhaust manifolds) but the pyro on that's been broken long enough that I don't remember whereabout it ran.
 
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Pat Dolan

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If you are running pre-PowerJoke 6.9 and 7.3s, you need to pay especially close attention to the SCA level in the coolant. THAT is what blows holes in the cylinder bores (from cavitation). Take an SCA kit (dip paper strips) to your next junkyard search, and don't buy something that doesn't have full value. If you were a bit closer, I could give you some (they are or at least were cheap).
 

[486]

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'powerstroke' was when they started with HEUI and direct injection
6.9s had no troubles with cavitation, the IDI 7.3s did

they went to a totally different bore spacing and everything on the DI 7.3, so it is pretty safe to assume the cylinder walls are a lot thicker than the IDI's
 

[486]

Top Post Dawg
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MN
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well, 37 gallons in and my first secondary filter plugged up haha
not too bad at 10 bucks apiece, but I'm thinking about a centrifuge

using BF7587 secondary filters and an 8psi lift pump, BTW
 

WarmStart

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Estonia
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TDI
Same time when I was using hydraulic oil my friend was using WMO and diesel 50:50. It weard out his injector pump and nozzles. He runned thru his DI engine 600 litres of WMO. He did not use any extra fitration.
 

[486]

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MN
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so, a hundred or so gallons in and I pulled my injectors for white smoke at idle, huge amounts of coke in there but they pop tested okay, just as junk of spray pattern as when they went in. Can't recommend DSS injectors. Plus side is the uncentrifuged oil put through a 2 micron filter is not destroying the nozzles near as quick as people seem to believe.

Got some $30 aliexpress chinese junk ".30" nozzles in there now. Had the same white smoke at idle issue, until I gave it a few hard pulls to knock the coke loose and it cleared right up. I'd been driving it gentle because I thought it was a streaming injector, but nope, just gotta see 1600 degree EGTs from time to time.

Oh, got a fuel pressure gauge now. The filter I thought that I'd plugged up? Flows fine again just by shaking it vigorously to get the particulate to settle to the bottom of the can.
 

DudaEnergy

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Madison, AL
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2003 VW 1.9L
I have a 1986 V6 Detroit Diesel All American Bluebird bus which I pretty much always ran WVO in without issues. However, veggie became scarce at one point and I tried using 100% motor oil. 200 miles into the drive the engine couldn't maintain an idle without stalling. I was blowing sparks and massive amounts of black smoke after about 450 miles. To no one's surprise, the injectors were junk and had to be replaced with refurbs. Then I gambled with running the motor oil again and the same problem happened again after about 400 miles. So I never used motor oil again.


Now blended it might be ok especially in small concentrations but I have heard horror stories from others (if mine isn't the worst since I was traveling 900 miles and went through this plus plugged fuel filters from bacterial growth when I finally decided to run just diesel sheesh!) The engine is just a simple supercharged 2 cycle so you'd think out of all engines that it'd do well. Nope.
 
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