Never using a 40wt oil again!!

[OVERKILL]

Originally Posted by yowps3
I wonder why Europeans recommend 40 wts while American and Japanese are recommending thinner and thinner grades.
Especially on today's motors that are ultra hard on oil


My SRT calls for a 0w-40, as does the Corvette now. You'll find that most Hi-Po mills call for heavier oils and 0w-40, with its wide spread, is probably the most common flavour. This aligns with the expectation that these applications will encounter situations where oil temperatures are elevated (track days for example) and the additional protection is needed. This runs contrary to the expectations for most "appliance" applications where runs to Walmart and the Beer Store or loafing down the highway are not going to elevate oil temperatures. These are also the bulk of sales, so tiny incremental gains in fuel economy realized through the spec'ing of lighter oils have a cumulative effect on CAFE credits.

To ensure that the lighter oils will work suitably in these applications you'll typically find one or more safety mechanisms in place designed to keep oil temperature within an appropriate range and, if that cannot be done, reduce output:
- Oil coolers
- Increased sump size
- Finned oil pans
- Thermal castration mechanisms (PCM pulls power when oil temperature hits a threshold)

 

[demarpaint]

Originally Posted by jbutch

My engine is a TGDI and is between 2000-3000 rpm most of the time. However, this engine is extremely hard on oil, shearing a thick 30 weight to a thin 20 grade in a few thousand miles... Low rpms does not mean it's easy on oil imo.

Did you have a UOA done to rule out fuel dilution?

 

[ofelas]

Thermal castration ?
Thx for making me spew my first cold beer of the day

 

[OVERKILL]

Originally Posted by ofelas
Thermal castration ?
Thx for making me spew my first cold beer of the day

You are quiet welcome

Nothing like having your non-track Pack Mustang GT get neutered on the straightaway because Nanny caught the oil temp getting a bit too high. IIRC, it was SteveSRT8 who first observed it, I think it was at Homestead?

 

[jbutch]

Originally Posted by kschachn
Originally Posted by jbutch
My engine is a TGDI and is between 2000-3000 rpm most of the time. However, this engine is extremely hard on oil, shearing a thick 30 weight to a thin 20 grade in a few thousand miles... Low rpms does not mean it's easy on oil imo.

How do you know if it's actual mechanical shear or fuel dilution instead?


I'd say both, but mostly mechanical shear, BS reported only 0.8% fuel and the oil sheared from 11.67 to 7.68. I really doubt it' because of the fuel alone. You can go through my posts, I have multiple UOAs on this engine with 3 differents oils so far.

I am trying some non-RC oil right now to see if it will shear less.

 

[kschachn]

Originally Posted by jbutch
I'd say both, but mostly mechanical shear, BS reported only 0.8% fuel and the oil sheared from 11.67 to 7.68. I really doubt it' because of the fuel alone. You can go through my posts, I have multiple UOAs on this engine with 3 differents oils so far.

It could be, but Blackstone is completely incapable of determining accurate fuel dilution and we've also seen suspect viscosity measurements on here as well.

Most every UOA on here with viscosity deviation appears to be from fuel dilution and not mechanical shear.

 

[OVERKILL]

Originally Posted by jbutch
Originally Posted by kschachn
Originally Posted by jbutch
My engine is a TGDI and is between 2000-3000 rpm most of the time. However, this engine is extremely hard on oil, shearing a thick 30 weight to a thin 20 grade in a few thousand miles... Low rpms does not mean it's easy on oil imo.

How do you know if it's actual mechanical shear or fuel dilution instead?


I'd say both, but mostly mechanical shear, BS reported only 0.8% fuel and the oil sheared from 11.67 to 7.68. I really doubt it' because of the fuel alone. You can go through my posts, I have multiple UOAs on this engine with 3 differents oils so far.

I am trying some non-RC oil right now to see if it will shear less.


Blackstone's fuel dilution measure is so bad you might as well have called Miss Cleo. Look at Flashpoint, was it significantly reduced from the PDS for the product? That will at least give you a better idea.

It is VERY often that mechanical sheer gets blamed for what has actually happened due to fuel dilution.

 

[jbutch]

Originally Posted by OVERKILL
Originally Posted by jbutch
Originally Posted by kschachn
Originally Posted by jbutch
My engine is a TGDI and is between 2000-3000 rpm most of the time. However, this engine is extremely hard on oil, shearing a thick 30 weight to a thin 20 grade in a few thousand miles... Low rpms does not mean it's easy on oil imo.

How do you know if it's actual mechanical shear or fuel dilution instead?


I'd say both, but mostly mechanical shear, BS reported only 0.8% fuel and the oil sheared from 11.67 to 7.68. I really doubt it' because of the fuel alone. You can go through my posts, I have multiple UOAs on this engine with 3 differents oils so far.

I am trying some non-RC oil right now to see if it will shear less.


Blackstone's fuel dilution measure is so bad you might as well have called Miss Cleo. Look at Flashpoint, was it significantly reduced from the PDS for the product? That will at least give you a better idea.

It is VERY often that mechanical sheer gets blamed for what has actually happened due to fuel dilution.


I know all about BS questionable fuel dilution, but the viscosity of my oil sample dropped by 33% (11.67 to 7.81, I had the wrong viscosity earlier). How much fuel would need to be in my oil to cause that much of a drop? My math could be wrong, but if the gas had a viscosity of 0 (which I know it's not), I would have a third of the oil that is gas (assuming no mechanical shear)? Again, I could be wrong on that calculation, but 33% viscosity drop is quite a lot and surely cannot be all attributed to the fuel dilution.

The oil level stayed the same, it never went up or down at all during the oci.

If you look at UOAs of the same engine that ran with non-RC oils, the fuel dilution is there but the viscosity didn't drop as much.

Here is the thread with my UOAs: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4913012/3

 

[OVERKILL]

Originally Posted by jbutch

I know all about BS questionable fuel dilution, but the viscosity of my oil sample dropped by 33% (11.67 to 7.81, I had the wrong viscosity earlier). How much fuel would need to be in my oil to cause that much of a drop? My math could be wrong, but if the gas had a viscosity of 0 (which I know it's not), I would have a third of the oil that is gas (assuming no mechanical shear)? Again, I could be wrong on that calculation, but 33% viscosity drop is quite a lot and surely cannot be all attributed to the fuel dilution.

The oil level stayed the same, it never went up or down at all during the oci.

If you look at UOAs of the same engine that ran with non-RC oils, the fuel dilution is there but the viscosity didn't drop as much.

Here is the thread with my UOAs: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4913012/3


Luckily, the viscosity of gasoline is easily found, and that is 0.6cSt.

So, using your numbers from above in the Widman Mixing Calculator: https://www.widman.biz/English/Calculators/Mixtures.html

Yields a requirement of only 12.78% fuel to drop the visc to your 7.81cSt figure.

 

[jbutch]

Originally Posted by OVERKILL
Originally Posted by jbutch

I know all about BS questionable fuel dilution, but the viscosity of my oil sample dropped by 33% (11.67 to 7.81, I had the wrong viscosity earlier). How much fuel would need to be in my oil to cause that much of a drop? My math could be wrong, but if the gas had a viscosity of 0 (which I know it's not), I would have a third of the oil that is gas (assuming no mechanical shear)? Again, I could be wrong on that calculation, but 33% viscosity drop is quite a lot and surely cannot be all attributed to the fuel dilution.

The oil level stayed the same, it never went up or down at all during the oci.

If you look at UOAs of the same engine that ran with non-RC oils, the fuel dilution is there but the viscosity didn't drop as much.

Here is the thread with my UOAs: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4913012/3


Luckily, the viscosity of gasoline is easily found, and that is 0.6cSt.

So, using your numbers from above in the Widman Mixing Calculator: https://www.widman.biz/English/Calculators/Mixtures.html

Yields a requirement of only 12.78% fuel to drop the visc to your 7.81cSt figure.




I knew it must have been easy to calculate, thank you!

But still, I really doubt i had over 12% of fuel..

 

[OVERKILL]

Looking at your thread, going by the most recent sample, which was QSUD 5w-30?
Virgin: 11.60cSt
UOA: 8.62cSt
V Flash: 453F
U Flash: 360F

Blackstone fuel: 0.8%
Required fuel to account for visc loss: 9.4%

Which seems pretty viable, given the massive drop in flash point.

 

[OVERKILL]

Also, looking at the previous sample, which you said was PP? Assuming it's the "current" version:
Virgin: 9.8cSt
UOA: 8.05cSt
V Flash: 405F
U Flash: 390F (much better)
Blackstone fuel: 0.0%
Required fuel to account for visc loss: 6.7%

This seems reasonably consistent

The flash point on this one didn't drop anywhere near as much as it did on the subsequent QSUD run and the calculated fuel percentage is almost 3% lower to account for visc loss.

What were the previous oils?

 

[jbutch]

Originally Posted by OVERKILL
Also, looking at the previous sample, which you said was PP? Assuming it's the "current" version:
Virgin: 9.8cSt
UOA: 8.05cSt
V Flash: 405F
U Flash: 390F (much better)
Blackstone fuel: 0.0%
Required fuel to account for visc loss: 6.7%

This seems reasonably consistent

The flash point on this one didn't drop anywhere near as much as it did on the subsequent QSUD run and the calculated fuel percentage is almost 3% lower to account for visc loss.

What were the previous oils?


54k was mobil super 3000
59k to 64k was pp
After that, it was qsud

 

[OVERKILL]

Originally Posted by jbutch
Originally Posted by OVERKILL
Also, looking at the previous sample, which you said was PP? Assuming it's the "current" version:
Virgin: 9.8cSt
UOA: 8.05cSt
V Flash: 405F
U Flash: 390F (much better)
Blackstone fuel: 0.0%
Required fuel to account for visc loss: 6.7%

This seems reasonably consistent

The flash point on this one didn't drop anywhere near as much as it did on the subsequent QSUD run and the calculated fuel percentage is almost 3% lower to account for visc loss.

What were the previous oils?


54k was mobil super 3000
59k to 64k was pp
After that, it was qsud


OK, so there were two runs of PP?

If we look at that previous PP one compared to the 2nd one:
Virgin: 9.8cSt
UOA: 8.18cSt
V Flash: 405F
U Flash: 370F
Blackstone fuel: Trace
Required fuel to account for visc loss: 6.2%, so a bit less than the subsequent run.

And then if we look at the Super 3000 UOA:
Virgin: 11.7cSt
UOA: 7.28cSt
V Flash: 462F
U Flash: 375F (WOW!)
Blackstone fuel: Required fuel to account for visc loss: 15%

As you can see, calculated fuel percentage required seems to correlate reasonably well with drop in flash point. In every instance where the drop in FP has been massive, the calculated fuel percentage has been very high. Conversely, where the drop in FP is not super high, the calculated fuel percentage is significantly lower. Is there mechanical shear as part of this too? Perhaps a bit. But I'd wager the majority of the visc loss you are experiencing is related to fuel dilution.

 

[Gokhan]

Come on now, OVERKILL. 15% fuel dilution?? What are you doing? You're going to make the poor guy's car catch fire.

Gasoline is volatile. How can the fuel dilution be 15% when the oil warms up? With cold oil, perhaps around a few percent is reasonable.

2.5% fuel dilution gives about 25% drop in the flash point; so, that's somewhat consistent with the "wow" UOA jbutch got.

Unfortunately, the authors neglected the oil shear here, which was of course what happened with 5W-40 but they didn't even think about it:

https://iopscience.iop.org/article/10.1088/1757-899X/147/1/012124

That looks like mostly permanent oil shear. According to my calculations, temporary oil shear for PPPP 5W-30 is about 75% (HTFSV/HTHSV). If the permanent shear was the same, you would get about 7.3 cSt. So, 8.1 cSt sounds a reasonable shear.

Of course, Mobil Super has a lot more VII and you get a lot more shear.

It's not really the fuel-dilution effect you're seeing here. This engine evidently shears the VII polymers like cotton. Look at the table below and pick an oil with a good HTFSV/HTHSV ratio, toward the top. PPPP 5W-30 is the highest-rated 5W-30 in that respect. QUSD 5W-30 is VII-loaded and lowly rated as a result. Mobil 1 5W-30 flavors are lowly rated for the same reason -- an unfortunate drawback of an otherwise great oil. This is consistent with what jbutch is observing.

 

[ofelas]

I've pulled 2 out of 6 leaking injectors with worn out pintles - the oil tested at over 12% dilution.

I have no doubt another severely worn injector would have put it over the 15% dilution mark.

Luckily, #2 is a somewhat better lubricant than gasohol ;-)

And for those interested, yes, I replaced all 6 injectors on my buddy's truck.

 

[OVERKILL]

Originally Posted by Gokhan
Come on now, OVERKILL. 15% fuel dilution?? What are you doing? You're going to make the poor guy's car catch fire.

Gasoline is volatile. How can the fuel dilution be 15% when the oil warms up? With cold oil, perhaps around a few percent is reasonable.

2.5% fuel dilution gives about 25% drop in the flash point; so, that's somewhat consistent with the "wow" UOA jbutch got.


I wasn't stating that the 15% figure was accurate, simply that, without shear, that's how much fuel would be required to achieve that much visc loss. It's quite possible he is above 5% fuel. Even at that percentage, you are looking at a drop to 9.9cSt. Curious as to where this 25% figure comes from? When I had 5% fuel dilution (GC) on my M5 it dropped my visc from ~13.4cSt (M1 0w-40 SM) to 11.9cSt. Unfortunately, Toromont didn't provide flashpoint.

Looking at this Polaris example:
https://www.bobistheoilguy.com/foru...les-edge-0w40-cu-trending-up#Post5076678

He's got >5% fuel and visc loss was actually less than what I experienced. Unfortunately Polaris also doesn't show Flashpoint.

I did find a thread where the guy did two UOA's on PP 5w-30 with one lab doing GC and the other Flashpoint:
https://www.bobistheoilguy.com/foru...les-edge-0w40-cu-trending-up#Post5076678

Fuel percentage is shown as 3.0%, but Blackstone still shows Flashpoint at 400F, which is significantly higher than the UOA we are discussing with the same lubricant. Blackstone also shows fuel as Oh, and Blackstone's visc is 0.5cSt lower.... Make what you want of that.

For the sake of having everything in one spot:
Lubricant: Pennzoil Platinum 5w-30
PDS:
KV100: 9.8cSt
Flash: 405F

Earlier PDS:
KV100: 9.62cSt
Flash: 460F

jbutch UOA:
KV100: 8.18cSt
Flash: 370F
Fuel: Unknown

Linked VOA:
KV100: 9.55cSt

linked UOA:
KV100: 8.55cSt
Flash: 400F
Fuel: 3.0%
Calculated fuel required using current PDS: 4.63%
Calculated fuel required using older PDS: 4.0%
Calculated fuel required using VOA: 3.8%

 

[Gokhan]

Originally Posted by OVERKILL
I wasn't stating that the 15% figure was accurate, simply that, without shear, that's how much fuel would be required to achieve that much visc loss.

...

Curious as to where this 25% figure comes from?

I hear you.

I was looking at the paper I linked in my previous post.

I still suspect a lot of permanent oil shear in jbutch's engine. Regarding fuel dilution, I would drive for about 25 miles on the freeway before I sample for the UOA, which should take care of most of the fuel dilution so that I can see how bad the permanent oil shear or oil thickening due to oil oxidation is without worrying about the fuel in the oil.

 

[OVERKILL]

Originally Posted by Gokhan
Originally Posted by OVERKILL
I wasn't stating that the 15% figure was accurate, simply that, without shear, that's how much fuel would be required to achieve that much visc loss.

...

Curious as to where this 25% figure comes from?

I hear you.

I was looking at the paper I linked in my previous post.

I still suspect a lot of permanent oil shear in jbutch's engine. Regarding fuel dilution, I would drive for about 25 miles on the freeway before I sample for the UOA, which should take care of most of the fuel dilution so that I can see how bad the permanent oil shear or oil thickening due to oil oxidation is without worrying about the fuel in the oil.


I suspect some shear, but perhaps not as much as you do. Given his precipitous drop in flash point in almost every UOA, I think it would be prudent for him to use a lab that actually uses GC and can give him an accurate dilution figure. He may have an issue, but what Blackstone provides simply isn't sufficiently accurate to determine what that issue is.

 

[jbutch]

Originally Posted by Gokhan
Originally Posted by OVERKILL
I wasn't stating that the 15% figure was accurate, simply that, without shear, that's how much fuel would be required to achieve that much visc loss.

...

Curious as to where this 25% figure comes from?

I hear you.

I was looking at the paper I linked in my previous post.

I still suspect a lot of permanent oil shear in jbutch's engine. Regarding fuel dilution, I would drive for about 25 miles on the freeway before I sample for the UOA, which should take care of most of the fuel dilution so that I can see how bad the permanent oil shear or oil thickening due to oil oxidation is without worrying about the fuel in the oil.



Really interesting reading the replies in this thread even though I feel like I highjacked the thread, haha.

A few precisions, before sampling any oil to be sent to a lab, I always drive 20-25 minutes while the oil is at 90c-100c to try to clear out any excess fuel.

Also in all my OCIs, the oil has never move a millimeter up or down on the dipstick and I check it very often. Also, everytime I change the oil, it does not particularly smell like gasoline (this is very subjective though).

Curent fill is Rotella MV 5w30, an SN rated HDEO, this will be my first UOA with a non-RC (GF5) oil.

I'd like to send it to BS (to keep the trend) and mayne OAI, but its getting more expensive to do UOAs than actual oil changes...