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Discussion Starter · #1 · (Edited)
First some acronyms

WMO: waste motor oil

WATF: waste transmission fluid

RUG: regular unleaded gasoline

D2: pump diesel

W85: approximately 85% WMO to 15% RUG blend. Some users add 15% RUG to the WMO
such as 40 gallons WMO and 6 gallons RUG which is actually 87/13 or others
calculate by dividing the WMO amount by 0.85 to determine how much RUG to add
such as 40/0.85=47 so they add 7 gallons RUG for a 85/15 batch

Some other definitions:

Whole house water filter: This is a 10" cartridge filter housing available at
most hardware stores.

String wound filter: these are typically 10" cartridges that fit the above
housing. They are available at commercial supply houses such as McMaster-Carr
or Grainger Industrial Supply or elsewhere online. String wound cartridges are
nominal rated meaning they don't get all particles above their rating out.
Typically when using these several passes are made or the oil is recirculated
through them.

Absolute rated filter: These filters get about 99.9 percent of particles larger
than their rating out. They are more costly and normally have a lower flow rate
so they are normally used at the end of the process

Upflow processor: A 55 gallon drum set up to separate water and heavy
particulate from the WMO. Most include a drain valve in the bottom, typically a
pipe welded into the bottom side of the drum with a valve. The top of the drum
is sealed. The small bung has an 3/4" NPT elbow installed, then a ball valve and
a filter housing typically containing a 20 micron string wound filter. The
output of the filter has a hose barb and normally a 3/8" hose. This would lead
to a mixing drum. The larger bung has a 2" close pipe nipple. Inside this nipple
a length of 2" exhaust pipe is welded that extends down to about 6-8" from the
bottom of the drum when the nipple is threaded in. Next the top third of a
closed head drum is cut off and flipped over then threaded onto the 2" pipe
nipple forming a sort of funnel. This will hold about 20 gallons of oil. Here is
how the process works: First the barrel needs to be completely filled through
the funnel and all the air let out through the 3/4" ball valve then it should
sit at least 1-2 weeks. To operate the system fill the funnel with 20 gallons of
oil. Open the valve slightly until a very light drizzle of oil comes out of the
3/8" hose. Ideally it will take about a day and a half for all the oil to empty
out of the funnel. The flow slows down as the funnel empties. Since I make 40 +
7 gallon batches I continue adding my other 20 gallons of WMO as the funnel
empties. Once all the oil has emptied from the funnel into the drum and forced
clean dry oil out through the filter you may close the valve until the next time
you need to process oil. Periodically you should open the bottom drain and draw
off any water and sludge that is present, failure to do this will eventually
result in a barrel full of water and sludge.

Mixing barrel: There are several ways to do this. If you can weld I have found
the nicest setup to be a 3/4" pipe welded into the bottom side of the barrel
about 1/2" up from the bottom. Put a 3/4" ball valve on the pipe then a few
elbows and a 12-15" length of pipe to bring the pipe high enough to screw on a
filter housing. I have two filter housings in series each with a 5 micron string
wound filter. After the filters I attach my mixing pump. Mine is a gear pump
that is geared down to do about 3 gallons per minute (gpm) which is the max
rating of my string wound filters. If your pump will not pull through the
filters then you may try pushing instead, just be careful not to create too much
pressure especially if your pump is large. You want to either filter in a vacuum
(pulling) or under very little pressure so the filters catch as much particulate
as possible. Too much pressure will force particulate past the filters. The
output of my pump has a tee fitting with a valve on each side. One side goes
back into the mix barrel. The idea is to recirculate and mix the oil. My method
is to add my RUG to the barrel first then let my upflow drizzle in 40 gallons
over a couple of days. Once this is complete I stir with a wooden paddle then
turn on my pump for about 3 hours. In three hours roughly 180 gallons of mix has
gone through my filters. After recirculating I close the valve that goes back
into the drum and open the valve on the other side of the tee fitting. This
leads to a 5 micron absolute rated cartridge. I pump through this either into
storage or into my truck.

drmiller100 has a different "low buck" method that I will do my best to describe
here: He uses just a mixing drum, adds his WMO and RUG and mixes it up then lets
it settle for a day to two. He then uses a pump to pull the crud and water off
the bottom of his mix barrel. Next using a small diaphragm pump he recirculates
through two 5 micron cartridges and then through a spin on absolute rated fuel
filter and into his truck or storage.

I don't think either system is better than the other as both drmiller100 and
myself have had good luck with our respective systems. I will only say that with
the pre-settling and upflow processor I have never had an issue with water in my
fuel. My recommendation to novices using drmiller100's setup would be to add a
water block or water separator filter inline as a precaution.

Another method is to use a centrifuge such as a Dieselcraft. I won't get into
the details here but suffice it to say that centrifuging is essentially forced
settling using the g-force created by the spinning centrifuge bowl. I prefer the
cheap and easy method of just regular settling and filtering.
Here are some ideas I've found helpful. I like to pre-settle my oil for at least
a month before processing. What I did originally was weld some 3/4" pipes into
the bottom sides of 3 55 gallon closed top barrels. I put my collected oil in
these barrels and date them with marker on masking tape. Since my processing has
grown I now use a 275 gallon fuel oil tank for storage and pre-settling. I
always draw off the top of the settling barrels. On my tank I put a tap at the
54 gallon mark and draw from there. From time to time open the bottom valves on
the barrels to drain off any water and sludge you may find. I have found that
letting the oil settle this long really gets a lot of the junk out prior to
upflow processing and filtering. Another thing some of us have found is that
after mixing the RUG and WMO together if we let the mix sit for a day or two the
RUG causes more sludge to drop out of suspension. That is one of the reasons I
start with RUG in my mix barrel and then let the upflow slowly fill it. It is
also important to carry spare fuel filters, the tools to change them, and about
a quart of fuel with you, especially at first. We believe that something in the
oil cleans the inside of the tanks and fuel systems because normally when first
starting out you will plug 1-3 filters in the first 500 miles or less. Once the
crud is out of the tanks the onboard filters seem to last a rather long time but
it is still good practice to carry a spare filter and some fuel to fill it.

Many of us are running the W85 blend but consider this a starting point. A lot
depends upon the oil you collect, thicker oil will require more RUG to thin it
out while thin oils like WATF require less, sometimes as little as 10% RUG. I
have found that my W85 starts and runs well down to about 10F, below that I have
added about 10% D2 to thin it a little more but next winter I'll likely just add
5% RUG instead since I did try that successfully in the past few weeks.

I feel I must strongly urge anyone interested in getting into any alternative
fuel to get to know their vehicle on D2 for at least a month or two before
experimenting with alternative fuels. Also make sure everything is in working
order. There are several reasons for this. Mainly the naysayers will almost
always blame your fuel choice if your vehicle breaks down. The second big reason
is you want to know how your vehicle should start cold and drive on D2 so that
you can properly adjust your fuel. Properly blended WMO is indistinquishble from
D2 other than slightly quieter running (less diesel knock). Another
recommendation is to install a dash mounted pressure gauge after the fuel
filter. On amy IDI I just used a 15psi boost gauge and some nylon gauge tubing.
This lets me closely monitor my filter condition as well as how well my blend is
flowing at low temps so I can adjust accordingly. I find the first sign that the
filter is clogging is if the pressure drops a little during hard acceleration,
like 1-2 psi on the IDI. My truck drops 1/2 psi under hard acceleration with a
fresh filter regardless of fuel or temperature so that is my baseline. If you
are running an engine equipped with a Stanadyne DB2 injection pump DO NOT let
the pressure drop below 4psi, this will eventually kill the transfer pump
section of the pump because it will cause it to cavitate. This is why I highly
recommend the pressure gauge for the IDI trucks.

Well there it is, just about everything I know about running WMO in my vehicle
as well as what I have learned from others. Hopefully some of the other forum
members will chime in with some stuff I may have missed.

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1,726 Posts
Discussion Starter · #2 · (Edited)
Some useful facts


BTU Values in BTU per gallon:

No. 2 fuel oil (diesel): 138,500 Btu's per gallon. Flash Point 143F and
Autoignition at 410F.
No. 6 fuel oil (used motor oil): 153,000 Btu's per gallon. Flash Point 400-500F
Autoignition 500-700F
Biodiesel – Waste vegetable oil 120,000 Btu/gal. Flash Point 300F. Autoignition
Gasoline 125,000 Btu/gal. Flash Point -45F. Autoignition at 495F.
Hydraulic Oil ?Btu/gal. Flash Point 414F Autoignition 650F
Transformer Oil ?Btu/gal. Flash Point 300F. Autoignition 482F.

Environmental impact: While this will likely always be up for debate the "Green
perspective" per a member of the Green Party who posts here (drcampbell) is that
running WMO in a diesel engine is about the same as running diesel. My take on
that is they both pollute roughly the same. Furthermore very little WMO is
re-refined into usable motor oil, approximately 14%. The bulk of used oil is
burned in some fashion either for heat or for power generation. Bunker fuel used
to power large diesel engines such as ocean going vessels often contains used
motor oil. Depending upon viscosity and purity used WMO can be classified as
#4-#6 fuel oil. However one must consider the energy required to recycle oil,
even into plain oil bunker oil. First it has to be drained and collected then
driven to a collection center (using fuel to get there) from there is must be
processed and again transported to the location it will be ultimately used.
There may even be some transportation in between. All the while burning diesel
or gasoline to transport it and using electricity to process it. My guess is
that it's likely less of an impact to run it in your personal truck that have it
converted to bunker fuels.

Finally I have had to hear people tell me over and over again that WMO or WVO
will ruin my engine, coke the rings, fry the injectors etc. From my perspective
this simply is not true. I recently had a head gasket let go on my 6.9 engine. I
happened to have the 7.3 engine from my old van sitting on a pallet and figured
if I was going to do a gasket job I might as well do the entire engine and
install the 7.3 due to it's larger head bolts which work better with my
aftermarket turbo. At the time the engine had at least 30k miles running waste
oils. I ran WVO blends in the summer and WMO/D2 blend in the winter. Upon tear
down I was SHOCKED at how little carbon there was inside the cylinders, how
clean the valves were etc. The injectors were replaced before I bought the van
so I have no idea how many miles are on them. The IP was also worn when I got
it. After a junkyard pump failed on D2 I put in an ebay rebuild which also
failed in short order. I then installed a quality rebuild and have put about 35k miles in total on that pump
running waste oils 90% of the time. If I had to guess total miles on WMO blends
I would figure about 20k miles in total as I ran about 5-6 months of the year on
50/50 WMO/D2 prior to switching to just W85. The truck starts in cold weather
and runs great with plenty of power and almost zero smoke except at cold start
up and heavy acceleration (IP turned up). The amount of smoke appears to be the
same whether I'm running D2 or W85. Since I have now saved more than enough
money to REBUILD the entire engine I'm not gonna even bother listening to people
who swear I will ruin my engine. If on the odd chance it does wear out I'll just
rebuild it or buy a junkyard engine with the money I have saved. By my
estimation I have saved close to $6000 running waste oils in this engine alone.
That is including paying for my waste oil, cost of filters and my setup, the
thinning agent (D2 or RUG), and little things like disposable gloves and paper
towels for cleanup.

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373 Posts
rsr youve outdone yourself again here this is a great write up that i hope gets made into a sticky.

the only thing i would like to add to this is that i am running W85 exclusively in my truck (2000 7.3 psd with 226k) for the last 7k+ miles with out a problem and my truck would even start down to 0 degree with out adding any extra D2

and for the record im am running a system based off of rsr's design

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40 Posts
WMO vs. WVO important distinctions, if any?

EXCELLENT post, certain to get better & better. by way of clarity, please list differences, pros & cons about the different breeds of waste oil, if possible. Back to reading...

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Discussion Starter · #5 ·
EXCELLENT post, certain to get better & better. by way of clarity, please list differences, pros & cons about the different breeds of waste oil, if possible. Back to reading...
Perhaps drmiller can comment on that. I don't have enough experience with oils other than WMO and some WATF, usually mixed in with the WMO. I can say that most hydraulic oil and cutting fluid I have seen is definitely thinner than motor oil. I'll have some experience soon though, just scored 325 gallons of hydraulic oil and cutting fluid. My major pickup just got a second building that used to be a machine shop and the oil was left behind so I got it from them.

One more tip: If you can offer to pay for your oil if you think you've found a steady reliable source. This keeps the recycling companies away. I will typically pay about 10% the current pump price for diesel. I did this with my WVO sources after losing a few when diesel hit $4.50/gallon, once I started paying the collection companies couldn't get in the door. I still have one of those sources and I sell the oil on craigslist when I pick it up about every 4-5 months. I have no trouble selling dewatered 10 micron filtered oil in clean drums for $1.00/gallon, mainly because it's super clean and thin Chinese Restaurant oil.

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194 Posts
Thank you guys for this wonderful thread! intelligent people like yourselves are why people like me are not scared to try crazy things! ive been all over the internet looking for information and compiling (what i hope to be the best) i have little real world exp with biodiesel and diesels in general. i have been wanting to do this for years and i see this being my main resource for trouble shooting when i finally start setting up my system. its nice to see people on here with 10k+ miles on alternative fules and still going. great thread lets keep it going!

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this is a good 1. you have put a lot of good info in 1 tread.:thumbsup:

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44 Posts
Thanks for this thread! I was researching possibly making bio Diesel and happened across this! I own a Mechanis shop and thus have plenty of spare WMO WATF etc...

I wish you could post a drawing of your barrel/funnel set up for us dummies though!

I was about ready to buy some tanks for the whole bio diesel deal, I think I'll hold off now!

I want to try this very soon, we have two PSD's a 1999 7.3 and a 96 7.3 PSD.

We generate about 275 US gallons of WMO a month at my shop.

this is what we have at our disposal. a couple of 275 Gallon Waste Oil tank.
approx Qty of 10 55 gallon drums sealed top and a few with bung ring ( open tops )

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1,588 Posts
Most any waste oil works, except Gear oil is bad, and shock absorber oil is bad. Both make lots of smoke.
A little bit of "bad oil" doesn't hurt anything other then make stinky smoke.
ATF, hydraulic fluid, 5/32, 10/40, non detergent, all runs great.
You can run heating oil if you mix some Waste motor oil with it.

In my opinion you should mix the gas with waste oil thoroughly, then let it sit for 2 days to 2 months. I think "slime" settles to the bottom when you mix the RUG with the oil. If you do not do this, you can plug the in tank sock for a while.

Most of the trucks we start running bio diesel or W85 or WMO with plug filters for the first 150 miles or so. We believe the detergents in the oil knock the diesel crud loose from the tank and lines, and the crud goes through the pump and plugs the truck filter. If you are expecting it, this is not a big deal - just have a spare filter or two and know how to change it for the first little bit. Expect to plug one or two filters in the first 150 miles.

Once you get the crud out of your tank one time it will not build up unless you completely stop running WMO for many thousands of miles.

On mixing RUG with your oil, when in doubt, always use LESS gasoline then more. If you use not enough gasoline your truck will smoke at idle, smoke on acceleration and get crummy mileage. You can add a gallon or half gallon of gasoline to your truck's tank if you have too much smoke.
If you use too much gasoline your truck will run like it has modern crap fuel, have diesel rattle, get crummy mileage. If you use way too much RUG you can indeed hurt your engine.

If you use not enough RUG you just make lots of annoying stinky smoke, but don't hurt your engine.

Everyone successful uses a QUALITY 5 MICRON SPIN ON FILTER as the last defense before the fuel goes into your truck.
Mount this filter so all fuel goes through this filter as it gets pumped into your truck.

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117 Posts
There are drawings of the upflows, just hit upflow in the search bar.

There is a guy in Atlanta offering a 55gal drum full of hydraulic oil for free. I need drums and oil. Is it worth the 4 hour round trip drive and can I use hydraulic oil and RUG 90/10?

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Discussion Starter · #11 ·
As for settling once the RUG is added I've worked a way around that with the upflow system. First my upflow oil is at least 2 months old settling time then it goes into the upflow. Second I add my RUG to the mix tank first then start the upflow drizzling into it. It takes about 3 days at the rate I prefer to get 40 gallons of oil into the mix drum, I mix it gently each morning before work and let it settle again overnight. Of course I'm actually trying to catch this sediment with my filters and so far it's working pretty well. I have noticed that the longer my "raw" oil has settled the less "slime" I get in my mix. I had some oil that I processed recently that was 6 months old, I got hardly any slime on that batch.

Here's another tip for those with more modern engines or the time an patience to do it. Try water washing the oil. Basically just mist several gallons of water over the top of your oil and let it settle for awhile. The theory is that the tiny mist droplets with wash any water soluble contaminate down to the bottom of the barrel where it can be drained off easily. This is not part of my process but I have run into several guys on other forums who water wash their WVO so it stands to reason that is could work for WMO as well.

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Discussion Starter · #12 ·
Calculated values for W85

BTU/gallon: 148800
Autoignition Temp (avg): 584F
Flash Point: 376F

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444 Posts
Good info. Do you have a diagram or picture of the processing barrels? Visual learner here, I believe I understand what you are setting up with the barrels but would enjoy something visual to see.

Also a little more info on the pumps to move it through the filters.

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Great info! A couple of months ago I mentioned the use of WMO on and got bombarded with naysayers. Whitejon introduced me to this site and I have been on the alt fuels section almost everyday reading ever since! I've learned alot from you guys! Thanks again 5 star rating all the way!

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373 Posts
Great info! A couple of months ago I mentioned the use of WMO on and got bombarded with naysayers. Whitejon introduced me to this site and I have been on the alt fuels section almost everyday reading ever since! I've learned alot from you guys! Thanks again 5 star rating all the way!
welcome aboard lots to learn for sure and not many naysayers here when there are trucking running the blends to back it up:thumbsup:

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44 Posts
There are drawings of the upflows, just hit upflow in the search bar.

There is a guy in Atlanta offering a 55gal drum full of hydraulic oil for free. I need drums and oil. Is it worth the 4 hour round trip drive and can I use hydraulic oil and RUG 90/10?
too bad you dont live near Indy my shop generates 300-500 gallons of used Motor Oil and ATF a month. We have about 75-85 cars a week go through here.

lots of barrels too.

what can you do with Old anti freeze? :lol:
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