IVDs and oils with ANs/Esters

[SubieRubyRoo]

So I’m trying to flesh out some ideas for understanding but don’t know if any of our experts can go “on the record” with the information, but wanted to ask:

There are plenty of people here concerned about IVDs in GDI/GTDI engines, and it’s assumed by many here that the prime generator of these deposits are via the PCV by sucking oil into the intake without any gas wash to clean them. But it appears from my personal testing that a good portion of the additives in the oil stay in the pan, and a majority of PCV vapors are base oil alone even though there are some additives carried with the oil.

Since we’ve learned that ANs & POEs are very good at cleaning, in the ring lands as well, and clean, happy compression & oil pack rings should help keep all the combustion byproducts out of the oil itself, is there any data which shows if ANs & POEs will: 1. Volatilize and be carried with other vapors into the PCV tract, and 2. Clean surfaces or at least prevent deposits on surfaces the vaporized chemicals come in contact with?

Gist of the point- we know thanks to the experts that while in the pan everything gets cleaned by the AN/ester combo. But when these are sucked through the PCV into the engine, are they cleaning the intake valves on the way past, and are they cleaning anything in the combustion chamber (similar to PEAs)?

This would give those who are concerned about IVDs a way to minimize their risk via spending a little more money on the front side thru buying oils with ANs & Esters in them. Just a thought; I know this may be treading into proprietary info so I’m not sure if we’ll get much professional info here. But here’s to hoping the answer’s YES!

 

[buster]

I'm leaning towards yes, but to a limited extent. I think the unique smell and price of VME was due to some higher end base oil (just a guess). HPL also states that their use of select esters can help mitigate IVDs. I think using oils that contain a good dose of group V base oils can help, but to what degree I don't know. I've thought about moving to M1 ESP for this reason being it possibly contains more V than M1 EP, however the M1 Triple Action is a new formulation, and speculated to contain more AN baseoil.

 

[SubieRubyRoo]

I’ve got a case of Triple Action M1 EP 10w30, maybe I will try to pull some strings and see if I can get an FTIR to confirm some of the assumptions…

 

[Tom NJ]

Interesting question. A lot would depend on the volatility of the ester or AN, and therein lies the problem. POEs have very low volatility, about half the Noack loss of PAO at an equivalent viscosity. ANs are more volatile than PAO but less than an equivalent mineral oil. To get these chemistries to be carried in significant quantities with other vapors would require atomization into physical droplets, or the use of a volatile version of the ester or AN.

Pure speculation, but adding a light ester to the oil may have a positive effect on intake valve deposits. Likewise adding a volatile anti-oxidant such as phenothiazine or a light alkylated amine or phenolic may also help. The esters and anti-oxidants used in motor oils are currently selected for low volatility, not high volatility, so this would be a totally different approach to address a specific problem, and I don't know if it has been tried. There are many monoesters and diesters available in the 1-2 cSt @ 100°C range, and an ester such as NPG Divalerate or with another low molecular weight acid would have excellent polarity with a very high Noack volatility. Whether enough of these vapors would make it to the intake valves would have to be determined through experimentation.

The downside is that adding a highly volatile polar component to motor oil will increase the total Noack volatility and may affect the catalytic converter, oil consumption, and emissions. A low enough dose, however, may strike an acceptable balance. The combination of a light ester with a light anti-oxidant could be the answer.

 

[Astro14]

@Tom NJ - In other words, engineer the oil to have a volatile component, so that this component is drawn through the PCV in order to clean valves as it goes through.

The problem - aside from potentially contaminating convertors - would be both the finite life of that component and the rate of its consumption.

It's a consumable. How would you control the rate of vaporization? It would depend on the operating oil temperature, which is too variable. So, maybe it last 5,000 miles before it is all vaporized? Maybe 1,000 if the car is driven hard?

Interesting idea - but I am not sure it can be engineered across the broad set of operating conditions inside engines.

 

[travis8352]

I’ve got a case of Triple Action M1 EP 10w30, maybe I will try to pull some strings and see if I can get an FTIR to confirm some of the assumptions…

That would be awesome

 

[Tom NJ]

@Tom NJ - In other words, engineer the oil to have a volatile component, so that this component is drawn through the PCV in order to clean valves as it goes through.

The problem - aside from potentially contaminating convertors - would be both the finite life of that component and the rate of its consumption.

It's a consumable. How would you control the rate of vaporization? It would depend on the operating oil temperature, which is too variable. So, maybe it last 5,000 miles before it is all vaporized? Maybe 1,000 if the car is driven hard?

Interesting idea - but I am not sure it can be engineered across the broad set of operating conditions inside engines.

Yes the ester is a consumable and its life in the oil is a factor. How long the ester remains in the oil depends largely on the ester and the dosage, as well as other factors. Improving deposits, however, may not require a steady stream of ester vapor throughout the OCI, and a temporary dose of ester vapor over the first 1,000 miles of each OCI may be enough to keep valves clean. Again just speculating.

Forty years ago I developed a product for STP which they named "Motor Oil Antifreeze". Its purpose was to drop the W grade only of an oil to facilitate easier starting during a cold snap. The intended claims were: Improves engine starting in cold weather, Reduces battery draw in cold starting, and Improves fuel economy during warm up, all of which were supported by test data and a literature search. This product was based on a light ester and contained a full DI package.

I conducted a seven car field test on the product using company cars with three popular motor oils to determine the effect on low temperature viscosity and the product life. One pint (~7% ester) added to a crankcase lowered the borderline pumping viscosity (ASTM 3829) at -25°C of the oil by 50% without affecting the viscosity at 100°C. I monitored the ester content in the oil by gas chromatography, and half of the original ester dose remained after 1,000 miles and about 20% after 2,000 miles.

STP was impressed and wanted to market this as a winter product to complement their summer oil treatment. They took it as far as test marketing, and then dropped it when management changed.

Clearly we did not monitor intake valve deposits at that time, but 80% of this particular ester did volatilize during the first 2,000 miles and presumably some of this was picked up by the crankcase ventilation system. This ester was extremely light because its primary intent was to lower the cold temperature viscosity, but other esters are available with varying volatility and more polarity. Of course these were engines from the early 1980s and the results cannot be extrapolated to modern engines, but the concept may be valid, especially if combined with a volatile antioxidant.

 

[buster]

It was speculated by a few that VME's higher Noack was intentional for that purpose. I don't necessarily buy it, but it's an interesting idea.

 

[SubieRubyRoo]

Tom, really appreciate the history and insight into this issue even if some is speculation. You’ve got good experience and we can at least see where things may have progressed to since you retired.

Trying to learn and share with the board; as most know the walnut cleaning is quite expensive and may be reduced or eliminated by using oils with specific additives, but it also probably doesn’t hurt port injected engines either.

 

[ZeeOSix]

GDI engines only suck crankcase vapors into the intake manifold, and those vapors go past the intake valves. So obviously, the deposits on the intake valves are directly due to that vapor. I don't think any oil can be formulated to "clean" the intake valves - might be able to formulate an oil to help reduce volume of vapors (ie, very low Noack) and deposits, but there will always be intake deposits on a GDI engine.

IMO, the only things you can do to try and cut down the rate of intake valve deposits on a GDI engine it to: 1) Use as low of a Noack oil as you can, and 2) Install a good PCV catch-can. The only way to reduce the deposits is to reduce the volume of nasty crankcase vapors into the intake manifold. Beyond that, the actual physical cleaning of the valves is the only way to handle what preventive measures fail to do.

I'm glad I don't own any vehicles that are GDI.

 

[buster]

Zee you may be right but there are also some other theories, such as the oil coming in contact with the valves is whole oil and not vapor rendering low Noack not as crucial. Some have speculated that oils with better oxidation resistance and select group V base oils can potentially reduce the amount of IVDs. Sulfated ash may play a role too.

Some GDI engines don't have that much of an issue.

https://gmauthority.com/blog/2019/01/gm-patents-innovative-new-integrated-oil-separator-assembly/

 

[addyguy]

TomNJ:
Rislone DID market a product for many years called ‘winter start’ in the 1980’s through the early(?) 2000’s…was this the same product you developed, just picked up by Rislone?

 

[SubieRubyRoo]

GDI engines only suck crankcase vapors into the intake manifold, and those vapors go past the intake valves. So obviously, the deposits on the intake valves are directly due to that vapor. I don't think any oil can be formulated to "clean" the intake valves - might be able to formulate an oil to help reduce volume of vapors (ie, very low Noack) and deposits, but there will always be intake deposits on a GDI engine.

IMO, the only things you can do to try and cut down the rate of intake valve deposits on a GDI engine it to: 1) Use as low of a Noack oil as you can, and 2) Install a good PCV catch-can. The only way to reduce the deposits is to reduce the volume of nasty crankcase vapors into the intake manifold. Beyond that, the actual physical cleaning of the valves is the only way to handle what preventive measures fail to do.

I'm glad I don't own any vehicles that are GDI.

Zee, remember it’s not only oil vapors; there are combustion byproducts, water vapor, GDI soot, and then whatever comes out of the finished oil as well.

Reducing Noack would likely only impact a small portion of the total volume of PCV flow; in 2400 miles I got roughly an ounce of oil, but there’s no way to guesstimate the total volume that passed thru the system- it could be a 50 gallons of liquid that stayed in vapor form.

 

[Greasymechtech]

Deposits are caused by normal valve stem lubrication... the minute continuous valve seal leakage.

PCV is not a major contributor to intake valve deposits.

I haven't seen a GDI engine without the issue.

Longer vs shorter oil change intervals are also a contributor. Dirtier spent oil leaking past the valve seals???

I vaguely remember several years back that one of the additive companies was working on an oil based additive that evaporates and cleans the intake valve deposits. Didn't see anything positive come out concerning that R&D since its been silent since then.

 

[Rod Knock]

I remember all the speculation about how this "gem" was supposed to address IVDs:

 

[ZeeOSix]

Zee you may be right but there are also some other theories, such as the oil coming in contact with the valves is whole oil and not vapor rendering low Noack not as crucial. Some have speculated that oils with better oxidation resistance and select group V base oils can potentially reduce the amount of IVDs. Sulfated ash may play a role too.

Some GDI engines don't have that much of an issue.

https://gmauthority.com/blog/2019/01/gm-patents-innovative-new-integrated-oil-separator-assembly/

Yes. the better the "separator" (or PCV catch-can) works, the less oil and vapors will go into the intake and past the intake valves. GM probably developed that complicated separator design to try and reduce intake valve deposits as much as possible.

Those DGI engines that don't have much of on ITV problem may also have some kind of PCV separator that works better than others. Would have to do some investigation to find out.

 

[ZeeOSix]

Zee, remember it’s not only oil vapors; there are combustion byproducts, water vapor, GDI soot, and then whatever comes out of the finished oil as well.

Has it been proven that combustion byproducts, water vapor and soot actually create ITV deposits? And anything combustion byproducts and soot that get blow back up through the intake valve during valve overlap can't be doing much ... it it was, the exhaust valves would be a mess, and they aren't.

Reducing Noack would likely only impact a small portion of the total volume of PCV flow; in 2400 miles I got roughly an ounce of oil, but there’s no way to guesstimate the total volume that passed thru the system- it could be a 50 gallons of liquid that stayed in vapor form.

And how did your intake valves look? Did you have a baseline of them before you installed the catch-can to compare? How much oil does the engine use in that same 2400 miles of use?

On a side note - When gasoline was crap back in the early 80s, the gasoline could also cause ITV deposits on port fuel injected engines. And also clog up fuel injectors ... seen that 1st hand. That's when Chevron was one of just a few gasoline sellers back then who touted their gas's cleaning ability with Techron.

 

[ZeeOSix]

I remember all the speculation about how this "gem" was supposed to address IVDs:

Anyone know what the actual Noack of that oil was?

 

[Titan]

What about fuel dilution common with many GDI engines? Wouldn't that fuel be relatively easy to "vaporize" and show up in the PVC system (assuming the oil got hot enough)? Surely that's not a reason to accept fuel dilution...or, is it?

 

[SubieRubyRoo]

Has it been proven that combustion byproducts, water vapor and soot actually create ITV deposits? And anything combustion byproducts and soot that get blow back up through the intake valve during valve overlap can't be doing much ... it it was, the exhaust valves would be a mess, and they aren't.

I didn’t imply that it was intake tract reversion, and I don’t think it is either. We seem to agree it’s all PCV-circuit related, but I was wondering if that GDI soot, before it agglomerates in the pan (I.e. very soon after it makes it past the rings) is able to make it into the PCV and into the intake. Or, the commonly accepted guess at this point, if it’s all oil/additives that are causing the accumulations.

Also, I haven’t personally seen any threads about exhaust deposits on engines that are having the intake valves walnut blasted, but it seems to make sense that there usually only minimal deposits due to the temps in the exhaust port and the fact that there is usually some active flame going in the port under heavy acceleration.

I certainly don’t have the answers, and what I’ve seen publicly certainly doesn’t seem to answer the phenomena nor how to prevent the issue. This is just trying to piece together bits and pieces to see if we can understand if ANs & Esters, whether in the pan or if sucked into the intake, can minimize or eliminate IVDs.