Explain How Oil Can Make An Engine "Smoother"

Status
Not open for further replies.
Joined
Aug 12, 2005
Messages
4,563
Location
NW Ohio
Or rougher?

So many people on this board now offer anecdotal comments that a particular oil brand or viscosity grade makes their engine "smoother" or "rougher" or "more quiet" or "noisier." I'd very much like to know the science behind these comments.

I admit to being a doubter, especially on the rough or smooth aspects (I can see where viscosity might make a difference with noise) but I'm willing to be convinced if someone can come up with convincing information.

Conversely, if someone has info counter to that, let's hear it.

I sincerely hope this doesn't degrade into an utterly useless, bandwidth-wasting, feelings-hurting urination contest.

For myself, I honestly cannot think of how one oil or another can make an engine smoother or rougher.
 
Certainly, my cars and trucks are smoother after an oil change. Probably due to oil contamination and viscosity loss. I generally use the same oil every time.
 
I run M1 oil for 10K and see no differance at all after an OC. Since Fords now call for 5-20 I did see a very slight differance after changing to 5-20 from 5-30.
 
It's all mental -- It's what we WANT to hear or feel. No scientific basis at all. Just like people see UFOs or the "Marfa" lights.

I think this the worst way to evaluate oil because it is completely subjective -- not the way for BITOG to operate.
 
I suspect that at least some of it is the same phenomena that makes my car run smoother after I wash it.
grin2.gif


I have never noticed it after changing oil in a car, but my motorcycles definitely shifted more smoothly after an oil change, so might be going on. That's a bit different though.

I would like to see the results of a double blind test on the subjective perception of engine smoothness before and after an oil change. My money would be on no significant difference.
 
I just did an experiment running a very high ZDDP group III oil (5w-30) and this made the 1NZ engine smoother than any OTC GF4 oil ive run - but not as smooth as a heavier HDEO group II 10w-30; so viscosity does play a part. In Synthetics, Non-polar oils like PAO dont provide a lasting mono-molecular layer on parts - where the polymer stand up like "velcro". Maybe this is involved too. I am just at the tip of the oil iceberg, I bet an old oil formulator and taster would be able to answer your question as they have been in "the art" for a long, long time. You may have to lean the secret handshake though;)
 
Originally Posted By: Zedhed
It's all mental -- It's what we WANT to hear or feel. No scientific basis at all. Just like people see UFOs or the "Marfa" lights.

I think this the worst way to evaluate oil because it is completely subjective -- not the way for BITOG to operate.
EVERYTHING is in your head. Subjective evaluations are a huge part of life and learning. This reminds me of the "distortion wars" in the 70's and 80's with audio amplifiers where there was a race toward ZERO harmonic distortion and the amps sounded worse than ever. Years later it was found what was SUBJECTIVELY known all along, that a new form of distortion was created whilst lowering the measured #s to ZERO that was WORSE than the distortion that was eliminated. It was called T.I.M. and was clearly AUDILBLE but not measurable (or measured) at the time. A Small set of measurements tell just part of the story. I asked a Genie for a blond that was 5'8, 130lbs, blue eyes - and what I got was a 86 year old wrinkly, smelly old lady with emphysema!
 
Last edited:
Originally Posted By: XS650


I would like to see the results of a double blind test on the subjective perception of engine smoothness before and after an oil change. My money would be on no significant difference.
Most of my cars run worse after an oil change - it take a while for the initially high % of detergents to get used up before the AW and EP agents wont have to compete with them. Then the engine atarts to smooth out. (Unless or course you run a RACE oil with very low detergency)
 
Last edited:
Originally Posted By: ARCOgraphite
I asked a Genie for a blond that was 5'8, 130lbs, blue eyes - and what I got was a 86 year old wrinkly, smelly old lady with emphysema!


So what does she think about the "smothness" of the different oils?
grin2.gif
 
Placebo affect.Same as a wash and wax,It dosen't run or drive any better clean or dirty.Run the [censored] out of one and let it sit afterwards for a few days.It seems to be 'rested'up LOL.I remember that one as a teenager.
 
Last edited:
..all oils run smooth for me when fully warmed up..However..apon intial start-up my '86 vanagon will run smoother..less motor movement and the lifters fill up immediately with the very light oil such as 5w/20 as compared to 15w/40/50 or even 5w/40syn..my '86vw diesel since new has always used a heavy vis. oil and when useing 5w/20 again less shacking and rattle..I can immediately engage the gear and drive off..I have never been able to do that even when it was new..also the surpriseing thing, is that they use less oil between changes
 
Lower visc. lower oil pump drag? K&N filters add 20 HP. The placebo effect can net satisfaction results. Spending $7 for a qt of oil needs to be justified.
 
There has to be some difference between different brands and grades or we're all really wasting our time here! Are those differences enough to make a perceptable difference in the feel of an engine? I have "felt" diferences after a change. Seen minor fuel economy differences. Feelings are subjective, but they exist. Fuel mileage is documented but are the differences because of the oil or the stength of the wind that week? As far as the wash and wax, ya everything feels better when it's clean!

As has been said, a lot of syn is used for intervals that could be reached with dino but this makes one "feel" better. Any difference in "feeling" smother on a different oil?
 
NEVER EVER noticed any changes in smoothness or noise when changing oil regardless if it was same or different brand. But then again I follow a proper maintenance schedule and never allow bad oil to stay in the crank case.

I think that you might notice a difference if you went from using a non recommended spec of visc. to the correct spec or viscosity or if you changed out neglected oil with fresh oil.
 
It's mental. If you put SuperTech in an Ultra bottle people would never know the difference.
 
I went from a 0W-20 to a 0W-40 and noticed quite a bit of difference in the sound of the engine at startup. Also, at cold temperatures the 0W-40 made the engine much harder to start. At operating temperatures I noticed no difference in feel or sound of the engine. Personally, I don't believe there is significant difference in feel between brands or even close grades.
 
viscosity makes a difference. I really notice in my Honda when I use a 5w20 and accelerate up an incline when driveing to the coast. The motor is much louder than when I have 5w20 in than when I have 5w30.
 
Originally Posted By: rewote500
It's mental. If you put SuperTech in an Ultra bottle people would never know the difference.


Probably very true. That would be a great test!

I thought I felt a difference using the same oil. Just a change but I've always thought it was just in my head.
 
Status
Not open for further replies.
Back
Top