Shearing, dilution and low cSt questions

[caprice_2nv]

My girlfriend's 2013 sonata also has it. My 83 Caprice with a carburetor that needs a new choke thermostat coil also has some soot in the tailpipe but not as much.

Until I replace the choke stat if I start it in minus twenty to pull onto the street and let my girlfriend's car out of the driveway, when I come back twenty minutes later to restart my car i have to turn the key on and wait almost a minute for the choke stat to slowly open up the choke and start properly or it will try to flood itself. So running rich from that put some soot in the tailpipe but not as much as the properly running gdi 2.4.

 

[pitzel]

Originally Posted by turnbowm
Originally Posted by pitzel
....The cleanliness of GDI combustion also enhances the ability of such oils to withstand long drain intervals....

The incomplete combustion of GDI/TGDI engines is anything but clean. Wipe your finger around the inside of the tailpipe for a real shocker


UOA's, which are all that's relevant in terms of motor oil, tell quite a different story. The cleanest UOA's we've collectively seen, by far, are from GDI/TGDI engines in the UOA section.

 

[turnbowm]

Originally Posted by pitzel
Originally Posted by turnbowm
Originally Posted by pitzel
....The cleanliness of GDI combustion also enhances the ability of such oils to withstand long drain intervals....

The incomplete combustion of GDI/TGDI engines is anything but clean. Wipe your finger around the inside of the tailpipe for a real shocker


UOA's, which are all that's relevant in terms of motor oil, tell quite a different story. The cleanest UOA's we've collectively seen, by far, are from GDI/TGDI engines in the UOA section.

GDI/TGDI engines are known soot producers that contaminate oil and cause premature timing chain wear. Click on the link below for more info....

https://www.lubrizoladditives360.com/gdi-soot-a-new-challenge/

 

[pitzel]

Originally Posted by Bryanccfshr
Nope, not with abrasive soot that GDI produces.


Yet wear metals and insolubles have almost never been lower on the UOA's. So if the soot is abrasive, it sure isn't having any deleterious impact on the motor oil's operating characteristics itself.

Timing chains are wearing out (a previously unheard of phenomena) because of the ridiculous lengths and economizations (ie: on size) that are present. Gone are the 12" chains common with the OHV pushrod engines of the past. Todays timing chains have crazy lengths. A knee-jerk reaction to the "timing belts are bad, let's use a 'permanent' chain" trend that developed when V6 DOHC engines proliferated as pushrod designs were phased out and firms that advocated pushrod designs (ie: GM) were squeezed out of the marketplace.

Extended drain intervals also cause a significant number of operators not to even bother checking the oil for quantity. Low engine oil quantity is well known to cause a significant acceleration in timing chain wear due to the splash lubrication design in place for timing chains on many families of engines. Extended drain intervals *must* address the infrequency of discrete oil changes by mandating periodic checking and topping up of oil outside of the formal service interval.

 

[Bryanccfshr]

Or perhaps the efficacy of using uoas to measure oil wear protection needs to be questioned.


Originally Posted by pitzel
Originally Posted by Bryanccfshr
Nope, not with abrasive soot that GDI produces.


Yet wear metals and insolubles have almost never been lower on the UOA's. So if the soot is abrasive, it sure isn't having any deleterious impact on the motor oil's operating characteristics itself.

Timing chains are wearing out (a previously unheard of phenomena) because of the ridiculous lengths and economizations (ie: on size) that are present. Gone are the 12" chains common with the OHV pushrod engines of the past. Todays timing chains have crazy lengths. A knee-jerk reaction to the "timing belts are bad, let's use a 'permanent' chain" trend that developed when V6 DOHC engines proliferated as pushrod designs were phased out and firms that advocated pushrod designs (ie: GM) were squeezed out of the marketplace.

Extended drain intervals also cause a significant number of operators not to even bother checking the oil for quantity. Low engine oil quantity is well known to cause a significant acceleration in timing chain wear due to the splash lubrication design in place for timing chains on many families of engines. Extended drain intervals *must* address the infrequency of discrete oil changes by mandating periodic checking and topping up of oil outside of the formal service interval.

 

[caprice_2nv]

Originally Posted by Bryanccfshr
Or perhaps the efficacy of using uoas to measure oil wear protection needs to be questioned.


Originally Posted by pitzel
Originally Posted by Bryanccfshr
Nope, not with abrasive soot that GDI produces.


Yet wear metals and insolubles have almost never been lower on the UOA's. So if the soot is abrasive, it sure isn't having any deleterious impact on the motor oil's operating characteristics itself.

Timing chains are wearing out (a previously unheard of phenomena) because of the ridiculous lengths and economizations (ie: on size) that are present. Gone are the 12" chains common with the OHV pushrod engines of the past. Todays timing chains have crazy lengths. A knee-jerk reaction to the "timing belts are bad, let's use a 'permanent' chain" trend that developed when V6 DOHC engines proliferated as pushrod designs were phased out and firms that advocated pushrod designs (ie: GM) were squeezed out of the marketplace.

Extended drain intervals also cause a significant number of operators not to even bother checking the oil for quantity. Low engine oil quantity is well known to cause a significant acceleration in timing chain wear due to the splash lubrication design in place for timing chains on many families of engines. Extended drain intervals *must* address the infrequency of discrete oil changes by mandating periodic checking and topping up of oil outside of the formal service interval.



I vote this

 

[wemay]

Originally Posted by caprice_2nv
Originally Posted by Bryanccfshr
Or perhaps the efficacy of using uoas to measure oil wear protection needs to be questioned.


Originally Posted by pitzel
Originally Posted by Bryanccfshr
Nope, not with abrasive soot that GDI produces.


Yet wear metals and insolubles have almost never been lower on the UOA's. So if the soot is abrasive, it sure isn't having any deleterious impact on the motor oil's operating characteristics itself.

Timing chains are wearing out (a previously unheard of phenomena) because of the ridiculous lengths and economizations (ie: on size) that are present. Gone are the 12" chains common with the OHV pushrod engines of the past. Todays timing chains have crazy lengths. A knee-jerk reaction to the "timing belts are bad, let's use a 'permanent' chain" trend that developed when V6 DOHC engines proliferated as pushrod designs were phased out and firms that advocated pushrod designs (ie: GM) were squeezed out of the marketplace.

Extended drain intervals also cause a significant number of operators not to even bother checking the oil for quantity. Low engine oil quantity is well known to cause a significant acceleration in timing chain wear due to the splash lubrication design in place for timing chains on many families of engines. Extended drain intervals *must* address the infrequency of discrete oil changes by mandating periodic checking and topping up of oil outside of the formal service interval.



I vote this

+2

 

[Navi]

Ive done my homework on this one. Regular oils like Penzoil Platinum are great for regular engines but for diluters you need high hths, TBN and CST.

My vote is for Mobil 1 Delvac...they have a 5W30 and a 5W40. I pur 5W40 in my engines.

 

[RDY4WAR]

If there's one thing Shell gets absolutely right, it's their shear stability. Their star polymers are very shear stable. I wouldn't worry about it shearing out of grade, even when starting at just 9.5-9.8 cSt @ 100°C.

 

[4WD]

Been around for 50 years … so Shell does not drop viscosity from fuel dilution …?

 

[RDY4WAR]

Originally Posted by Bryanccfshr
Or perhaps the efficacy of using uoas to measure oil wear protection needs to be questioned.


As they should. UOAs tell you more about the oil's condition than the engine's condition. While high levels of iron, lead, or copper can indicate excessive wear, excessive wear can occur without any of those metals showing.

 

[pitzel]

Originally Posted by RDY4WAR
Originally Posted by Bryanccfshr
Or perhaps the efficacy of using uoas to measure oil wear protection needs to be questioned.


As they should. UOAs tell you more about the oil's condition than the engine's condition. While high levels of iron, lead, or copper can indicate excessive wear, excessive wear can occur without any of those metals showing.


Then what's the point of UOA, if the UOA's (on TGDI engines) come back clean as a whistle, yet there's all this alleged "accelerate wear due to soot"?

Is the soot-induced "wear" happening so fast that wear particles are deposited as large chunks of engine material in the filter or bottom of an oil pan? That doesn't sound even remotely plausible.

Wouldn't the soot show up as elevated insolubles, as it does in diesel engines with EGR that run extremely long drain intervals?

I'm just trying to get to the bottom of what I believe are irrational, not-supported-by UOA data claims that {T}GDI engines contraindicate long drain intervals. On nearly every UOA posted of a {T}GDI engine, the only issue that tends to arise is fuel dilution. Minor fuel dilution of long-drain interval viscosity-thickened lubricant may be beneficial from a fuel efficiency point of view and actually facilitate even longer drain intervals than in a non-fuel-diluting engine for which excessive viscosity thickening would result in oil exceeding condemnation limits.

 

[zeng]

+1

 

[Bryanccfshr]

Originally Posted by pitzel
Originally Posted by RDY4WAR
Originally Posted by Bryanccfshr
Or perhaps the efficacy of using uoas to measure oil wear protection needs to be questioned.


As they should. UOAs tell you more about the oil's condition than the engine's condition. While high levels of iron, lead, or copper can indicate excessive wear, excessive wear can occur without any of those metals showing.


Then what's the point of UOA, if the UOA's (on TGDI engines) come back clean as a whistle, yet there's all this alleged "accelerate wear due to soot"? .


Good question about the applicability/suitability of traditional uoas for this type of service.

 

[Bryanccfshr]

This is a paper describing the potential effects and the shortcomingS in trying to measure GDI soot in oil.

https://www.researchgate.net/public...e_using_Transmission_Electron_Microscopy

 

[pitzel]

Originally Posted by Bryanccfshr
This is a paper describing the potential effects and the shortcomingS in trying to measure GDI soot in oil.

https://www.researchgate.net/public...e_using_Transmission_Electron_Microscopy


Article says, (paraphrased), "GDI soot is a lot like diesel soot".

Is UOA invalid for diesel engines? No. Why would it be for petrol engines in determining efficacy of a lubricant?

 

[RDY4WAR]

My statement was in reference to wear metals, not soot.

 

[Bryanccfshr]

I suggest those who are curious actually read the paper and not trust anyone else's potentially biased "paraphrasing" including my own.


Below is an excerpt of the paper. It is important to use defat and the limitations of the scope of different papers to take portions or the whole into proper context.

" oil. Sootis likely to migrate into the oil ï¬lm early during the expansion stroke[8]; consequently, the morphology, agglomeration and other charac-teristics of soot-in-oil are likely to be rather different to exhaust soot.Soot-in-oil has not been subject to oxidation processes to the sameextent and hence the outer shell structure is more likely to remainintact. Although only a small proportion of the soot formed in thecombustion chamber transfers to the engine oil, it contributes to thelubricant degradation. This is certainly a new challenge for the modernGDI engine as soot-in-oil raises concerns upon wear and enginedurability. It is well established that oil thickening has a complexdependence on soot [9]. Various investigators [10,11] have shown thatdiesel soot build up in oil gives rise to increased engine wear rates;Gautam et al. [12] reported that wear increases with higher sootconcentration. Soot reduces the effectiveness of anti-wear additivesand its effect on wear depends upon the characteristics of the particlesand agglomerates of soot. Abrasive wear occurs and wear scar widthclosely matches the primary particle size [10]. Oil thickening wasfound to enhance timing chain elongation due to abrasive action ofsoot on pins and bushing [13]. Bardasz et al. [14] studied the influenceof high number of engine cycles on lubricant oil and that of oilcharacteristics on engine wear, comparing direct injection and portfuel injection engines and ï¬nding increased wear for the ï¬rst category.There is also a growing interest within the automotive industry tobetter understand the complex interactions between soot morphologyand properties of lubricating oil."

Originally Posted by pitzel
Originally Posted by Bryanccfshr
This is a paper describing the potential effects and the shortcomingS in trying to measure GDI soot in oil.

https://www.researchgate.net/public...e_using_Transmission_Electron_Microscopy


Article says, (paraphrased), "GDI soot is a lot like diesel soot".

Is UOA invalid for diesel engines? No. Why would it be for petrol engines in determining efficacy of a lubricant?

 

[wemay]

While we sit here debating soot, viscosity. dilution, wear, gdi, tgdi, lspi etc., I keep seeing tons of first generation GDi Hyundai. Kia, Ford, Mazda, GM products on the road, seemingly running just fine.

 

[Bryanccfshr]

Originally Posted by wemay
While we sit here debating soot, viscosity. dilution, wear, gdi, tgdi, lspi etc., I keep seeing tons of first generation GDi Hyundai. Kia, Ford, Mazda, GM products on the road, seemingly running just fine.


True. But have been issues with intake deposits, timing chain lengthening and LSPI causing failure that have been addressed through warranty and post warranty repairs, engineering controls such as injector design and configuration and with oil specification once the nature of the initial problems were recognized.
Dispersants keeping the soot from bonding together seems to be the answer to soot. One thing that I don't know is how long those dispersants are effective.