How much is too much gasoline in a waste oil blend?

363
7
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Location
Prescott, AZ
Blending gasoline at 20% with WVO has worked pretty good for the last 6 years for my old 6.2L Detroit Diesel engine; however, going over 20% increased the likelihood of injector pump failure. So, I recently made up sample blends and put o-rings: Buna-N 70, Silicone 70, V75 Viton in them and left them to soak.

Stanadyne DB-2 injector pumps use both Buna-N 70 and Silicone 70 o-rings. I found in my experiment that Buna-N 70 o-rings can handle blends containing up to 50% gasoline; however, I also found Silicone 70 o-rings will swell significantly in blends containing 40% or more gasoline; whereas, blends containing 30% or less gasoline will not swell either o-ring; and V75 Viton will not swell. Please photo below:

Source:
How much is too much gasoline in a waste oil blend?
 

silverstate55

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FANTASTIC info, thank you very much!! I'm glad that I replaced the O-rings with Viton ones in my Deuce engine's HH...I get old gas every now & then, but I try to keep it below 10% total concentration with my WMO/UMO blends for my Deuce.
 

wreckerman893

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When I was making "deuce juice" my mix for 100 gallons of fuel was 30 gals WMO, 30 gals WVO, 30 gallons straight diesel and 10 gallons of gas to thin it out. Worked well but you have to use it immediatly or it will try to settle out.
 

camp9

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Yooperland, Mi
How many miles have you put on in 6 years. You still have the original IP it came with? How cold have you ran with your blend? Thanks for sharing.
 
363
7
18
Location
Prescott, AZ
Nice write up about o-rings.... Have you considered on looking into how much gasoline will lean the diesel motor out to much for catastrophic failure....?
Thanks, gungearz, other aspects of how much gasoline is too much in a normal diesel engine also involves energy content (BTUs), cetane, lubricity, specific gravity, viscosity.

energy content (BTUs):
Gasoline has on the average 10% energy per unit volume than diesel fuel; whereas, waste oils tend to have about 10% more energy per unit volume than diesel fuel; therefore, a blend of 50% gasoline to waste oil should have the same energy content per unit volume as diesel fuel has.

cetane
Cetane is the value that a fuel has that promotes diesel combustion. it is the inverse of octane rating, which is the suppression of diesel combustion. Gasoline does not have 0 cetane. It has octane enhancers added to it to reduce diesel combustion. I do not own a cetane, or octane testing device, so I will have to determine this by using my blends as a fuel.

Lubricity:
I plan to build a lubricity testers, but I believe it is reasonable to consider that a gasoline blend with waste oils, even up to 50% gasoline, should have at least the same lubricity as D2 diesel.

specific gravity
I have tested the specific gravity of blends of new canola oil and gasoline; and new 10-40 motor oil and gasoline, and found a 50-50 blend of either produces a blend with the same specific gravity as D2 diesel fuel.

viscosity
I have tested the viscosity of blends of new canola oil and gasoline; and new 10-40 motor oil and gasoline, and found a 50-50 blend of either produces a blend with the same viscosity as D2 diesel fuel.

However, it is reasonable to consider that a waste oil-gasoline blend containing gasoline at 50% might have sufficient cetane value for diesel combustion. I do know that waste oil-gasoline blend containing gasoline at 30% run like racing fuel in my old engine, so I am inclined to continue increasing gasoline in my blends, but I will first have to replace the silicone seals in my IP.
FANTASTIC info, thank you very much!! I'm glad that I replaced the O-rings with Viton ones in my Deuce engine's HH...I get old gas every now & then, but I try to keep it below 10% total concentration with my WMO/UMO blends for my Deuce.
With Viton o-rings, and no silicone o-rings, in your IP, then there is no reason why you could not run higher percentage of gasoline in your waste oil diesel blends. Also, what swells the silicone seals is the presence of alcohol in our oxygenated fuels. Stale gasoline is most likely going to have very little, if any, alcohol in the fuel.
When I was making "deuce juice" my mix for 100 gallons of fuel was 30 gals WMO, 30 gals WVO, 30 gallons straight diesel and 10 gallons of gas to thin it out. Worked well but you have to use it immediatly or it will try to settle out.
There is a definite problem with blending WVO with WMO, because there are lacquers and free carbon that are dissolved in the WMO that will precipitate out when WVO is blended with the WMO, and that lacquer is bad news. Click the link for a lengthy discussion and exploration of Blending WMO with WVO Incompatibility
How many miles have you put on in 6 years. You still have the original IP it came with?
My odometer does not work, so I do not know how many miles I have driven in the last 6 years, but not a lot, because I often drive a company truck when I work.

I do not have the original IP, because when it first died I sent it off for a rebuild. However, I have four IPs now, 3 of which are dead, and at least one of them has a split silicone seal. Now that I know that silicone seals with swell significantly in fuel blends containing gasoline at or above 40%, then I plan to rebuild all three IPs and replace all of the silicone seals with viton if I can find them, or BUNA if not.
How cold have you ran with your blend? Thanks for sharing.
I have had not trouble starting my 6.2L Detroit Diesel engine without a block heater in temperatures at 0F (-18c) on a blend of 20% gasoline to 80% canola WVO.
 
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363
7
18
Location
Prescott, AZ
So far I have been pulling working IPs off of wrecks at the junkyard. I plan to rebuild the pumps myself. I will need a source of seals as soon as I identify which seals I will be replacing. I have already looked around for seal kits, and no one seems to offer that in a set of stock seals, let alone a set of viton seals.
 

Ford Mechanic

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Edenton, NC
Is it just me or has anyone else noted higher EGT's with diesil than gas to cut WMO? I normally cut my 50 gal tank with 5 gal diesil, 10 gal gas, and the rest WMO. Just for kicks this time I cut it 10 gal diesil, 5 gal gas, and the rest WMO, and noticed almost a 30* increase in EGT! Anyone else see this or why?
 
363
7
18
Location
Prescott, AZ
30° what? F or C? I noticed that my engine's EGTs vary widely dependent upon RPMs, from 300F to 1100F, so it is hard for me to see any difference between running straight D2, verses various WVO-gasoline blends. I would have to log data points per unit time and compare curves over several runs over the same terrain to see any difference.
 

Ford Mechanic

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Edenton, NC
30* F All flat land here. Yeah mine also vary per the rpm, but i'm mainly noticing it in 5th.......

Gotta go....Will tell more later, first job of the AM came in.
 

Ford Mechanic

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Edenton, NC
Back for a moment.... Like I was saying, I notice it in 5th mainly. I don't even look at the EGT until I get into 4th, and I do notice it in 4th it's just I'm under the heat I want to stay at so I don't pay it much thought. As far as in 5th I noticed (more diesil) between 1800-2200 rpms depending on throttle input I have to be real careful and checking the EGT. I'm backing off at 1160*F and got more pedal availible. With more gas I have less problems with heat (easyier to keep under 1160*) and can use more pedal in it
At 55 cruising it's also running about 1110*F where as with more gas to cut it with it's running 1080*F or so. Am I just trying to keep the heat to low? I'm also running the 395's so I know they're not helping. I'm trying to switch they now with someone for the 44's, what ever they were called. My WMO is a mix of 5w20-15w40, to trans fluid.
 
363
7
18
Location
Prescott, AZ
Thanks, it is very useful to know that running gasoline in your blends tends to cool your engine slightly. I had guessed so, because gasoline has less BTUs per unit volume than diesel fuel, but WMO has more BTUs per unit volume than D2, so I figured the blend would result in roughly the same over all BTUs per unit volume. Apparently not.
 

Kalashnikov

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NH
I've been running WMO blends exclusively in my 89 and 93 F350s with 7.3 IDIs that used the DB-2. I use a mix of about 40/60 stale RUG/WMO and it was about the same viscosity as diesel and the same starting characteristics and smoke. I tried a 50/50 mix and it was just a little too much RUG and the 89 wouldn't start. So far I have about 5k mi on each since a rebuild on the pumps and new injectors.

This is my winter blend. This summer I hope to run a few tanks of 100% hydraulic oil from the supply I've gathered over the winter months and then return to 100% WMO until the weather gets cold again.
 

brianp454

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Portland, OR
So far I have been pulling working IPs off of wrecks at the junkyard. I plan to rebuild the pumps myself. I will need a source of seals as soon as I identify which seals I will be replacing. I have already looked around for seal kits, and no one seems to offer that in a set of stock seals, let alone a set of viton seals.
As an engineer, I've been designing and specing in viton o-rings and seals for many years. It's a great material! Chemical compatibility is wonderful and also can handle a very wide range of temperatures. I've purchased in small quantities from California seal here on the left coast (they have a warehouse and will call in Portland). You can also get them from McMaster-Carr and other online industrial supply places. If you do an internet search of chemical compatibility you will find lots of info published by the elastomer manufacturers.

I'm very curious if someone has broken down an IP\HH assembly and documented all of the o-ring sizes. Do any of you have any knowledge of someone doing this? If they did I could kit them up quite easily. If you do an online search you can get the standard sizes from a long list of places. I particularly like to the Parker O-Ring manual becuase it also has some excellent design info. Even if the old o-ring is torn up, you can figure out the size by measuring the Internal Diameter (ID), Outer Diameter (OD), and Cross Sectional thickness to sort it out. Generally if you use an o-ring that is a little smaller on the ID and has the correct cross sectional thickness you are OK. I sometimes get one size below and above to see which fit I prefer. I would imaging that most of the seals in the IP\HH are static, they are typically more relaiable than dynamic seals. I'd love to have a spare IP and goof around with this.

Feel free to send an PM if you have any questions you think I can help with.
 

trukhead

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dane/wi
Will a lubricity additive that makes up the difference between old style diesel fuel and todays miracle ULSD fuel, when added to the above mentioned WMO and gasoline mixtures result in a fuel with the appropriate lubricity to sustain the FI parts of the fine old 6.2 Detroit assuming the appropriate seals in the IP?:?:
 

brianp454

Member
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Location
Portland, OR
Will a lubricity additive that makes up the difference between old style diesel fuel and todays miracle ULSD fuel, when added to the above mentioned WMO and gasoline mixtures result in a fuel with the appropriate lubricity to sustain the FI parts of the fine old 6.2 Detroit assuming the appropriate seals in the IP?:?:
I don't know anything specific to your 6.2 Detroit, yet would think as a general rule that adding a quart or two of well-cleaned and dewatered WMO to each fill up would make up for the lack of sulfur for lubricity. I would think other places on the web would have better info on your particular engine (was it used in military tucks?). The commercial additive you mention should also do. You may want to check with the manufacturer of the additive to see if they have a chemical compatibility list. If they don't get specific (buna nitrile, silicone, viton, etc.) I wouldn't trust that they've really done their homework. My 2 cents.
 
363
7
18
Location
Prescott, AZ
I agree, once you have added any waste oil to gasoline at 70% or more the resulting fuel blend should have plenty of lubricity.

Brianp454. I would be very interested in a Viton seal kit for a DB2 IP, if you come up with such a kit. The DB2 IP has at least one silicon seal, which I know fails from gasoline blends; however, that seal is not just an o-ring. It looks like a mushroom, and I have not seen seals like that in any seal catalog. So, good luck, for a worthy venture, because I have 3 dead DB2 IPs that need to be rebuilt.
 
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