Engineering Explained - Engine oil and valve deposits

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Originally Posted by PimTac
Originally Posted by Gokhan
The video makes the false claim that vapors coming from the PCV attributed to the NOACK volatility cause the intake-valve deposits. This myth has been debunked with scientific research papers. Intake-valve deposits are caused by the PCV-oil-mist droplets containing the full additive package, not base-oil vapors arising from the NOACK volatility. So much with this video deserving merit.





So you disagree with the experts at Valvoline?


Why would someone who is a poster child for the concept of a little knowledge being dangerous hesitate to disagree with the folks from Valvoline or any other concern?
 
I thought the video was pretty good in explaining in layman’s terms how oil could cause valve deposits. To have someone come in and debunk it based on papers that he didn’t link to is bad science.

Now I expect we will see multiple links backing up his basis.
 
Originally Posted by PimTac
I thought the video was pretty good in explaining in layman’s terms how oil could cause valve deposits. To have someone come in and debunk it based on papers that he didn’t link to is bad science.

Now I expect we will see multiple links backing up his basis.


I like the video and have no issue with his explanation. Nor do i care that Valvoline sponsored. They don't appear to have influenced his material and any discussion of VME was prefaced by "Valvoline claim..."
 
Originally Posted by wemay
Originally Posted by PimTac
I thought the video was pretty good in explaining in layman’s terms how oil could cause valve deposits. To have someone come in and debunk it based on papers that he didn’t link to is bad science.

Now I expect we will see multiple links backing up his basis.


I like the video and have no issue with his explanation. Nor do i care that Valvoline sponsored. They don't appear to have influenced his material and any discussion of VME was prefaced by "Valvoline claim..."





I agree. It was handled well. My assumption is that Valvoline is not alone in this. I’m sure all the major brands are on the same path.
 
The video is not made by Valvoline, although sponsored by them. I took an issue with the false statement made that lower NOACK will decrease the amount of PCV mist coming and forming deposits on the intake valves. I'm repeating my post with the paper by Afton/SAE (no, it's not bad science).

Formation of Intake Valve Deposits in Gasoline Direct Injection Engines
Gregory Guinther and Scott Smith -- Afton Chemical Corporation
October 17, 2016
https://saemobilus.sae.org/content/2016-01-2252

I will put their conclusions here. IVD means intake-valve deposits.

SUMMARY/CONCLUSIONS

* A standardized, vehicle-based GDI IVD test has been developed that is both repeatable and responsive to known additive chemistry.

* Higher engine loads lead to an increased rate of deposit formation.

* IVD formation in this protocol is an oil-related process, and the majority of the oil that finds its way onto the intake valves comes from the PCV system.

* The oil leaving the crankcase through the PCV system is whole oil containing additives and contaminants (not distilled base oil vapor which contains no additives).

* PCV gas flow in the intake manifold is inconsistently distributed among the eight runners of the manifold leading to the valves.

* Inhibiting the carbon-formation process lessens the rate of deposit formation on the intake valves.

* Oil consumption past the rings bring both additive and nonadditive elements into the combustion chamber where they are incorporated into the exhaust-gas particles.

* Particles found in EGR exacerbate deposit formation rate.

* Particles found in EGR appear to incorporate combusted oil additive components, engine wear metals, and ambient air contamination.

Gregory Guinther and Scott Smith
Afton Chemical Corporation

Note the conclusions I highlighted. They are saying that the main source of the intake-valve deposits is PCV. However, it's liquid oil (whole oil) coming through PCV as a mist, not evaporated oil (oil vapor). So, the amount of oil coming through PCV has nothing to do with the NOACK volatility.
 
Gokhan,

I got the impression from the video that certain polar molecules created a situation where they would not build up on engine parts. In a way it is a end run around Noack.

Maybe Noack is not as relevant in these newer oils ? There was a recent discussion as well about new test methods for volatility.
 
Originally Posted by PimTac
Gokhan,

I got the impression from the video that certain polar molecules created a situation where they would not build up on engine parts. In a way it is a end run around Noack.

Maybe Noack is not as relevant in these newer oils ? There was a recent discussion as well about new test methods for volatility.

They were talking about detergents and dispersants. Ironically, the detergents are the main source of the intake-valve deposits in GDI engines, while the video praises them. Also, every oil has detergents and dispersants; so, what do they claim that they are doing differently?

I know the Amsoil SS 5w30 and old Pennzoil Ultra 5w30 without PurePlus did well in TEOST 33C. Since these are PAO-based oils, perhaps excellent base oils such as PAO make a huge difference in deposit formation.
 
Originally Posted by Gokhan
...
* The oil leaving the crankcase through the PCV system is whole oil containing additives and contaminants (not distilled base oil vapor which contains no additives).
...
So, the amount of oil coming through PCV has nothing to do with the NOACK volatility.]
You've admitted elsewhere that volatility does affect oil consumption. Where does that missing oil go, if not via PCV into the combustion chamber in volatilized form? And then it burns cleanly, without leaving deposits anywhere?
 
*Issues with Pennzoil Platinum DEXOS 1 Gen 2 SN+ ?
Originally Posted by Oildudeny
I'll be honest i am for trying different oils. There's nothing like Mobil 1, Valvoline and Castrol. The 3 top dogs and only 3 really needed.
 
Originally Posted by Gokhan

* IVD formation in this protocol is an oil-related process, and the majority of the oil that finds its way onto the intake valves comes from the PCV system.

* The oil leaving the crankcase through the PCV system is whole oil containing additives and contaminants (not distilled base oil vapor which contains no additives).
.
.
.
Note the conclusions I highlighted. They are saying that the main source of the intake-valve deposits is PCV. However, it's liquid oil (whole oil) coming through PCV as a mist, not evaporated oil (oil vapor). So, the amount of oil coming through PCV has nothing to do with the NOACK volatility.



That second dot point is erroneous or misleading.

The presence of additives in the deposits does NOT mean that volatility is not the transport mechanism.
 
Instead of the engineers depending on the oil to correct the problems they engineered in, why not re-engineer, improve and correct the design causing the problems? Or is that something they aren't capable of doing yet? I realize they work/worked on it, but seeing all these articles and discussion leads one to believe they still aren't there yet.

The
27.gif
emoji doesn't work.........
 
Originally Posted by Shannow
Originally Posted by Gokhan
* IVD formation in this protocol is an oil-related process, and the majority of the oil that finds its way onto the intake valves comes from the PCV system.

* The oil leaving the crankcase through the PCV system is whole oil containing additives and contaminants (not distilled base oil vapor which contains no additives).

That second dot point is erroneous or misleading.

The presence of additives in the deposits does NOT mean that volatility is not the transport mechanism.

It's not clear in the summary conclusions they wrote because I can't post the whole paper due to copyright issues. Basically, they looked at the ratios of the elements in the whole oil and compared them to the deposits and they found that the ratios are the same. That's how they reached the conclusion that the deposits are caused by the whole oil and not the vapors.
 
Originally Posted by Shannow
Originally Posted by Gokhan

* IVD formation in this protocol is an oil-related process, and the majority of the oil that finds its way onto the intake valves comes from the PCV system.

* The oil leaving the crankcase through the PCV system is whole oil containing additives and contaminants (not distilled base oil vapor which contains no additives).
.
.
.
Note the conclusions I highlighted. They are saying that the main source of the intake-valve deposits is PCV. However, it's liquid oil (whole oil) coming through PCV as a mist, not evaporated oil (oil vapor). So, the amount of oil coming through PCV has nothing to do with the NOACK volatility.



That second dot point is erroneous or misleading.

The presence of additives in the deposits does NOT mean that volatility is not the transport mechanism.


Q1:
don't additives also evaporate (~%20? of the content, %80? base oil)? If they do, then noack volatility can be the transport mechanism.

Q2:
What is the typical evaporation temperature of the additives? Below, at or above the base oil? That would determine the amount.

Q3:
This is Where I get confused.
Where does the evaporated oil condense? Isn't there a lot more cold(er) places (besides the back of the intake valve) for the oil to condense along the way. I am talking about the pcv route.
 
Originally Posted by OilUzer
Q1:
don't additives also evaporate (~%20? of the content, %80? base oil)? If they do, then noack volatility can be the transport mechanism.

Q2:
What is the typical evaporation temperature of the additives? Below, at or above the base oil? That would determine the amount.

Q3:
This is Where I get confused.
Where does the evaporated oil condense? Isn't there a lot more cold(er) places (besides the back of the intake valve) for the oil to condense along the way. I am talking about the pcv route.


Noack has traditionally been used to protect the exhaust aftertreatment devices...

The oil film on the walls is exposed to ring belt temperatures (around the 250C mark) , and as the piston descends, whatever heat is in the combustion chamber and cylinder as the piston descends.

And the oil evaporates, contributing to HC and CO emissions, and the additives that they take with it end up in the cat converters...

The phosphorous is the key target for testing, as it poisons catalysts, and is volatile, and the (for e.g.) calcium stays behind. Can measure the Ca increase as oil is burned off, and measure the P in the condensed Noack Vapors.
http://www.bobistheoilguy.com/forum...ring-belt-residence-time-and-degradation
I liked that paper...

The Selby paper I linked to shows the P transport. And some of the Ca left behind.

Gokhan's link showed both the Ca left behind in volatility, and that there was whole oil transport into the intake, and identified the PCV as the vector.

I disagree that GDI is "bad engineering"...it's not, it was the holy grail when I did my engineering.

But if you have a look at the trends of the last 20 years, I think bad engineering is the issue
* the OEMs have been trying to normalise ridiculous oil consumption (1qt/600 miles for some engines in Oz), and pushing for reduced P at every revision of the standards
* in normalising ridiculous levels of oil consumption have allowed all the other oil and additive in the intake (and per Gokhan's paper circularly through EGR as well after combustion) to raise Havock.

Reduce oil consumption, and you reduce oil consumption related issues...honestly, 1qt/3,000 miles wasn't that hard, back before all these "precision" machining methods were adopted, but tighter engines are by definition "tighter", and have more parasitic drag when tested...(won't mention the conspiratorial nature of the tests).

Now for a brain squeeze...is the combustion of engine oil measured in the standardised testing ?
F1 used engine oil to boost power/miles travelled...does the oil consumed in the economy tests add another 0.05% to the fleet average ?
As a manager, I know that you always get the behaviours that you reward, whether that's your intention or not...
 
The 'fix' or at least the reduction of valve deposits
will likely not be a cheap one.
Better baffling of the PCV and possible coating the
back of the intake valves (ceramic?) would both help.
I've seen the crud in 'catch cans' on some GM engines
and it's almost scary.
Toyota's dual injector method isn't cheap either.


My 2¢
 
Now for a brain squeeze...is the combustion of engine oil measured in the standardised testing ?
F1 used engine oil to boost power/miles travelled...does the oil consumed in the economy tests add another 0.05% to the fleet average ?
As a manager, I know that you always get the behaviours that you reward, whether that's your intention or not...


This is a really interesting thought.
Could oil burned as fuel be intended to reduce observed fuel consumption in emissions cycle tests?
Sneaky but possible, never mind that even cheap motor oil is a whole lot dearer than any motor fuel.
 
Originally Posted by fdcg27
This is a really interesting thought.
Could oil burned as fuel be intended to reduce observed fuel consumption in emissions cycle tests?
Sneaky but possible, never mind that even cheap motor oil is a whole lot dearer than any motor fuel.


Don't get too deep down the rabbit hole, and this weekend I will suss out the test durations but 1qt/600 miles, and if the test runs for 600 miles at 30MPG is another 0.3MPG as measured form the gas tank.
Just an idea that popped into my head.
 
Last edited:
Originally Posted by demarpaint
Instead of the engineers depending on the oil to correct the problems they engineered in, why not re-engineer, improve and correct the design causing the problems? Or is that something they aren't capable of doing yet? I realize they work/worked on it, but seeing all these articles and discussion leads one to believe they still aren't there yet.

The
27.gif
emoji doesn't work.........

EFU engineering face up. So to cover the behinds, it was the oils fault. This stuff is complicated. Like most stuff we never get the whole truth and mostly misunderstanding
 
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