Reclaiming fuel contaminated oil

burbguy82 said:
two samples...same pil

one with fuel dilution

one without

krl test........

which one shears more?
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It depends on shear forces and specific circumstances. Most engines do not tend to shear the VM.

But also in general the presence of fuel is detrimental to the VII in the oil. Use an oil with no VM and there won’t be any shear regardless of fuel.
 
kschachn said:
It depends on shear forces and specific circumstances. Most engines do not tend to shear the VM.

But also in general the presence of fuel is detrimental to the VII in the oil. Use an oil with no VM and there won’t be any shear regardless of fuel.
Click to expand...
what is VM?
 
burbguy82 said:
So if there is no VM, then fuel has no effect on shear stability?

Do most common off the shelf brands use VMs?

Which do not?
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No, there is nothing to shear. Oil molecules will not shear in an engine, the shear forces are nowhere near great enough to do this.

As noted, nearly all oils use VII except monogrades and a couple muti-grade oils that could also be labeled as a monograde. But the shear stability is dependent on the quality of the VII as well as the tendency of a specific engine to cause shear.
 
kschachn said:
No, there is nothing to shear. Oil molecules will not shear in an engine, the shear forces are nowhere near great enough to do this.

As noted, nearly all oils use VII except monogrades and a couple muti-grade oils that could also be labeled as a monograde. But the shear stability is dependent on the quality of the VII as well as the tendency of a specific engine to cause shear.
Click to expand...
As normal, I am misunderstanding something. Please help me understand.

If a motor oil starts off at viscX, and ends at viscX-1......that is due to viscosity modifiers "losing a battle"

If in an engine oil does not make oil shear, then what causes the viscosity to change?

Is it the fuel "attacking" the VMs and not the "oil"?????
 
burbguy82 said:
As normal, I am misunderstanding something. Please help me understand.

If a motor oil starts off at viscX, and ends at viscX-1......that is due to viscosity modifiers "losing a battle"

If in an engine oil does not make oil shear, then what causes the viscosity to change?

Is it the fuel "attacking" the VMs and not the "oil"?????
Click to expand...
Fuel dilution is essentially a lower viscosity fluid being mixed with one of a higher viscosity. If there is fuel in the oil then it will lower the viscosity of the oil just by being there regardless of whether it is a monograde oil with no VII or a multi-grade.

VII degradation is a separate issue. Fuel does attack the polymer molecule and can cause both temporary and permanent damage just by itself. Look it up, there are lots of sources on this.

The other way VII is degraded is by mechanical shearing of the VII molecule. This can be exacerbated by the presence of fuel.

https://www.infineuminsight.com/media/1813/2-viscosity-modifiers-na.pdf
https://www.infineuminsight.com/media/2606/emea-viscosity-and-viscosity-modifiers.pdf
https://www.savantlab.com/testing-highlights/viscosity-loss-its-only-temporary/
 
oil pan 4 said:
The main reason I do oil changes on my wife's car is fuel dilution, because its a direct injected hybrid. I hate effing gasoline DI.
The only thing that fixes fuel dilution is running it on the highway for extended time or changing the oil. This car is driven about 8 miles each way when my wife goes to work or less when we go to the store, then occasionally do road trips and those seem to happen less frequently now.
To get the oil from a stinky 4% to 5% of fuel down to less stinky 2% takes about an hour drive at 75mph, so that's an hour plus about 2 gallons of gasoline just to get an improvement and it's not a great improvement.
To really drive the fuel out of the oil it needs more like 4 to 5hr of driving at 75mph that will get it below a half percent, I did dump the oil and pull a sample that time, had I known it was less than a half percent I would have ran that oil longer.
That's a lot of time, miles on the car, gas money and tire wear.
So simply dumping and refilling $25 worth Pennzoil platinum looks pretty appealing.
What if there was a 3rd option.
Just cleanly and nearly remove the oil from the car then simply heat the oil up to drive off the fuel?
Even better do it under a vacuum.
Yeah, yeah ya, I know it would never be worth it to get a vacuum pump and build a heated vacuum dryer tank to save $25 worth of PP twice a year and I agree.
But what if I already had all that stuff?
I've had my little 2 stage vacuum pump since forever, since the early 2000s.
Back around 2006 I built my first heated vacuum drying tank for waste vegetable oil, then in 2007 I built a bigger better replacement, went on deployment, came back found the entire areas supply of WVO was locked down by some evil vegetable oil racquet and all I could get was small amounts of WVO from one place. So I never used my second generation heated vacuum dryer and it's been shelved ever since.
I'm thinking add an oil drain valve to the car as the oil drain plug is smartly elevated above the road surface, that's the only part I would have to buy and the car is done. Then take my vacuum dryer tank weld in a bung for a tempature gauge (already have a temperature gauge in my junk collection, have weld in bungs in my bunghole box) and there's already bung to connect a hose for filling and draining the tank. I also have a used hydraulic hose and line collection, so don't even have to buy a hose. So when it's together all I have to do is suck the hot oil out of the oil pan after a drive with the vacuum dryer, run it, heat the oil up a little bit more that normal under vacuum and push the oil back into the oil pan with compressed air the same way it came out and the whole process takes the same amount of time as doing an oil change hopefully. Maybe add some recreational plumbing so I can pull samples.
If it works switch to a better oil like amsoil or hpl. As of now it's not worth wasing great oil on fuel dilution driven oci ranging 3,300 to 6,600 miles.
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I would use NAPA synthetic.

I would make sure your homeowners insurance is up to date. Maybe get an umbrella policy also in case you burn down the neighborhood vs just your own house or garage.
 
Donald said:
I would use NAPA synthetic.

I would make sure your homeowners insurance is up to date. Maybe get an umbrella policy also in case you burn down the neighborhood vs just your own house or garage.
Click to expand...
How do you know how much fuel is in it?
 
Astro14 said:
Since the oil is going to get diluted, why use “great oil”?

Why not use “good” at a lower price point, and dump it when it gets contaminated?

Either way, you’re under the car, draining the oil out. Whether you put the drained oil in your oil reclamation device, or simply recycle it, the amount of labor getting it out is the same.

But the amount of labor to reclaim it, in order to save a couple bucks on the oil, doesn’t seem like a very good return on the investment of all that time in reclamation.

Driving for an hour costs significantly more than a new jug of oil anyway, so don’t bother driving off the fuel. That’s a waste of both time and money.
Click to expand...
This is my current dilemma in my Accord with the K20c4. It dilutes. 4% at 4500 miles on Valvoline Restore and Protect 5w30.

So I'm testing some thicker HPL 15w-40. I'm hoping the the dilution is lower, but more importantly that the viscosity margin can shrug off some dilution and hopefully get to 10k OCIs with a clean sample showing this to be OK.

But if I can't make 10k on HPL, there's no reason to run the fancy oil when I could just run Euro FS for 5k OCIs and be done with it. And while I didn't like the high dilution and low viscosity of Valvoline Restore and Protect 5w30 as it got near 5k, the wear metals were superb (6 ppm Fe) and the cleanliness was excellent, so on 5k OCI, the Valvoline Restore and Protect 5w30 might be fine to run indefinitely.

If Valvoline would just give me a 40 grade or 50 grade Valvoline Restore and Protect all my problems would be solved.
 
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