Oil and engine noise - My kitchen table test

[Rodbuckler]

Hi, I'm new here and this is my first post. I have been lurking and searching info for a couple of months, and I have really learned alot from this forum. I hope I can add to the knowledge base.

I see alot of talk about oils and engine noises, both topside and bottom end. Cold and hot viscosity have alot to do with the noise, but I find that once I am using the correct hot viscosity oil that the stickiness or "hang" will determine the level of engine noise. Higher RPM noise or harshness is something I especially hate, and I tune it out with my oil selection.

The test: Pour the unaerated test oils 1/4" deep straight down the center of new thin clear plastic drink cups that you find at the grocery store. Carefully tip the cups such that the side is wetted, but not as high as the deformation found at the top of the side. Watch all the oil flow back down into the cup base for a while, then check the next day.

The quieter oils will retain 100% coverage of the original wetted surface. The noiser oils will shed off the plastic, and leave dry spots.

My controls:

M1 10w30 SS: The king of shed, noisiest oil I've ever used
Delo 400 15w40: The king of stick, cured many a noisy engine
GC: The best of the synths I've tested

A few observations:
M1 5W-20: Better than the 10w30 SS
MC 5W-20: Sheds some, and noisy in my ragged out 4.6L
PP: Very promising, and it goes in tomorrow
Delo SAE 30: Not entirely like the 15w40

What are your results and experiences?

 

[GMorg]

Rodbuckler,
I think that I have noticed a similar thing for my noises when hot. I have not decided if I favor viscosity or adhesion as the answer, but I am leaning towards viscosity. My wifes Ford Sable wagon get very noisy in the summer in the mountians. A little 20W50 spike fixes it right up. The valve chatter just goes away. (Manual recommends 5W20)

However, I have noticed an opposite effect on cold noises. My 2005 Montana SV6 (3.5l V6) is very noisy until warm in the winter. I can "cure" cold noise by adding a little 5W20. (Manual recommends 5W30 and specifically states not to use 10W40 nor 20W50)

 

[Rodbuckler]

Gmorg,

The hot/cold viscosity and stickiness thing isn't that easy to figure out for a given engine. The top end and bottom end sometimes want different things. Also, the percentage synthetic that you use determines how consistent the viscosity will be hot to cold. Piston slap might love an oil that is thick when cold, while the hydraulic lifters might want it thin when cold. Hot noise needs to be soothed at low and especially high RPM.

My advise is to start with a sticky oil and nail the hot viscosity through blending. Then go to your oil of choice and compare results.

 

[427Z06]

New thin clear plastic drink cups? How are they in anyway similar to the metal in your engine? Maybe the oils that stick to your plastic cups are sticking to the underside of plastic valley covers, manifolds, etc, and dampens the noise emanating from those regions. Just as reasonable a theory as any other.

Heck even if the oil sticks to clear plastic drink cups the same way it sticks to the metal in your engine, it doesn't in any way measure it's lubricity, among other important properties an oil in your engine should have. The sound difference could again just be due to the oil sticking to the underside of valley covers, manifolds, valve covers, timing chain covers, etc, and providing a noise dampening effect. Now that I ponder it a bit, that sounds like a more reasonable theory as to why some people hear differences between different oils.

 

[JAG]

Welcome Rodbuckler. We live in the same city and both do oil experiments at home. Wow, 2 oil geeks in the same area! I like your tests. Recently I noticed something about the oil I'm currently using that relates to your tests. I put it only about 3 weeks ago. It's Lubromoly 0W-40 which is PAO based with some mineral oil additive carrier. I noticed that when I check my dipstick, a tiny bit of the oil will pull away from the metal dipstick and leave a few tiny dry spots in random locations. I never noticed that with many other synthetics of similar viscosity that I've used and know the dipstick doesn't have any foreign substance on it that would repel the oil. So I think this is due to this oil having lower polarity than others I've used; as you know in a liquid on a surface the cohesive forces "fight" the adhesive forces (from polarity) and when a dry spot appears, it means the cohesive forces exceeded the adhesive forces.

I think what you are oberving in your tests is amount of the oils' polarity - assuming the plastic is polar. IS the plastic polar? Another test of polarity is to put the liquid in a small diameter glass (polar) tube and look at the shape of the miniscus: polar liquid will make it convex and non-polar will make it concave. I've done this in a plastic syringe and always saw a convex miniscus with every oil including the Lubromoly 0W-40. But what I want to do is put them in again and observe how convex the different oils' minusci are to gauge their polarity.

A few years ago I did another test. I heated up a drop of Redline and other oils on a steel plate to see how much the drops would spread out. The viscosity grades were equal. The Redline drop spread out significantly more than the other oils. So that result proved to me that Redline's esters do add significant polarity. And it really did seem to make my engine at the time quieter as many others have said too.

Is your GC the Green or Gold version?

 

[Rodbuckler]

Thanks for the welcome JAG!

I do alot of experiments, and not just on oil. So that kind of makes me an all-around geek to be certain.

The plastic cup in question seems to mimick what I see on metal as far as polarity goes. This is especially good since I had tried few media, and I can see through the cup to see what is going on during the test. The controls are essential. I also do a drip test on the oil bottles to see the spread or shed...same results.

Hey, was that you who opened 2 of the 7 bottles of GC that I purchased at the Mine Road AZ? You missed the green one. The green and the gold tested similar, but the gold seemed like it was thinner at room temp. Perhaps it is a better oil.

 

[JAG]

Ah, the Mine Road Autozone...while I am guilty of opening one bottle of what turned out to be Gold GC, I noticed that there were already some opened bottles before I got to them. So we must have some other green GC hunters in the area! I never did find a green GC bottle but I really want some to do some high temperature tests on alongside Gold GC.
After my last post, I put my dipstick in virgin Lubromoly 5W-40 oil and no dry spots appeared like they did with the 0W-40 version (so the latter is uniquely strange). They must be quite different in formulation and I know their additive packages are quite different from UOAs.

I'm going to find some plastic cups to do the tests you did with all of the oils I have on hand.

 

[GoldenRod]

You forgot to mention which viscosity of Pennz Platinum you plan to use!

 

[Rodbuckler]

Goldenrod,

Of course I will be blending

(2quarts 5W-20, 4quarts 5w30). These mix visually as if they are the same. I get power loss in my back-spec'd modular if I go above 10cSt at 100C. I get high RPM noise with the scratchier oils at 9.5cSt and below.

I will see what happens, and top off up or down in viscosity. Tomorrow is today, so I will find out soon.

 

[427Z06]

Rodbuckler, I'm greatly leaning to the theory that this phenomenon that people describe is nothing more than a difference in sound dampening due to differences in cohesive and/or adhesive properties of the oils in relation to the internal surfaces of the engine. Kinda' like the Space Shuttle Sound Suppression System.

Non-Newtonian characteristics may further influence some of the sound dampening capabilities of different oils as they adhere to the engine's internal surfaces.

 

[GoldenRod]

So then you're shooting for a cSt number between 9.5 and 10.0 at 100C? Why not just use an oil speced at 10.0 cSt?

 

[Rodbuckler]

There are no sticky synthetic or semi-synthetic oils spec'd at 10.0cSt that I know of. And I'm fresh out of SL rated M1 10w30. PP is our greatest hope for a quiet off-the-shelf full-synthetic for sub GC viscosity usage.

 

[Rodbuckler]

427Z06,

I understand your point. It's like the arguement over whether the engine runs cooler on synth oil than dinosaur squeezin's. We know the water runs cooler, but what about the oil and the average temp? Nobody knows, but it helps the water stay in the race engine.

The engine noises I hear are twofold: General noise and specific noises. The general noise might be felt less with a stickier oil, yet the causes of the general noise remain persistent regardless of the oil you use. The energy is dissipated either by the parts or by the oil. I like the oil to take the energy from the general noise because it frees up my senses to feel for real mechanical problems.

Specific noises can be cured by the oil selection by eliminating the impact that caused the source of the noise. So the dissipation of the noise energy does not have to occur. This is the one that I pay real attention to at higher RPM. I've felt the power go up when the noise went down, and that is scary.

 

[mechtech]

M1 is a fine oil, but many have observed a noisier engine with it it.
So maybe there is some validity in your tests.

 

[Titan]

Ever notice how some oils creep further up the dipstick than others? I think all of them do creep, but, some creep much more than others. That information and 2.99 will get you a small cup of coffee at some of these coffee houses!

 

[oilyriser]

Surface tension. Different detergents? I noticed the old SL Tech 2000 recycled oil would bead up on the dipstick and the drain plug. Maybe it's the silicone anti-foam additive. Try adding some silicone grease to the oil and see if it changes the stickiness in this test.

 

[427Z06]

Rodbuckler, I haven't yet heard, or been able to measure with a sound meter, this Mobil 1 noise phenomenon. Even if it does exist, it's harmless as demonstrated by numerous UOAs. But it does help explain why some people, who consult with their Feng Shui consultant before they change their oil, can detect such differences. It's simply dampening out the higher frequencies before they're transmitted outside the engine. In short, it's a bunch of people worrying about nothin'.

 

[Gary Allan]

Hmm ..sounds like a task for Quietrain® with Acousticsolve®, wouldn't you say ??? This post may entertain you, Rodbuckler


Most somatic complaints that I've observed here fall into the hot viscosity audio realm. I simply interpret it to be the nature of too low a visc at too low a flow rate at idle. Or maybe an adaquate flow rate (obviously these engines are not being damaged) at too low a visc for sound dampening. Given the broad range of viscs, even within a given viscosity grade, it's surely possible ..probable infact, that you're going to fall outside a visc for all seasons/situations over the life span of an engine ...and maybe right out of the box. Some will fall into "conflicting complications" and will be forced to compromise ..where they will have a demand for cold start performance ..at the cost of hot idle annoyance.

The world is an imperfect place.

If you are annoyed by HLA sound (the most cited complaint) at idle ..then you can go up in visc to cure the apparent symptom. Although I've "felt" differences (which could be a combination of dampened vibrations that may or may not be manifested in sympathetic audio co-emissions) with radical changes in visc (like going from 5w-20 to 20w-50) ..I think most of us would be hard pressed to distinguish the finer differences that you're tuned into here. That is, outside of the obviously apparent cold vs. hot idle or cold start type symptoms

I've never pondered the finer properties of two like visc oils in terms of "acoustic dampening" (outside of the aforementioned post)

Interesting discussion.

 

[JAG]

quote:

---

Originally posted by 427Z06:
Rodbuckler, I'm greatly leaning to the theory that this phenomenon that people describe is nothing more than a difference in sound dampening due to differences in cohesive and/or adhesive properties of the oils in relation to the internal surfaces of the engine. Kinda' like the Space Shuttle Sound Suppression System.

Non-Newtonian characteristics may further influence some of the sound dampening capabilities of different oils as they adhere to the engine's internal surfaces.

---

That's what I'm thinking too.

 

[Rodbuckler]

The amount of vibration from the engine that makes it to my body is markedly influenced by the nature of the oil in the crankcase. The ones that bead give a harsher feel, and the ones that stick make me want to hit the starter as I drive down the highway. It is not a subtle difference in some of my engines.

I put SM rated M1 5w30 SS into the LT1 last time. I look down the oil fill hole and can see hot oil beaded on the cleaner-than-new head. The stickier oils just give a wet look all over on the spotlessly clean aluminum surfaces of my modular motor head.