INDYMAC

I realize that I am more interested in tribology than most on this forum, so this research paper might not appeal to some people here. But I think that even if you don't use clean and used oil analysis to help you decide when to change your lubricants, you can gain something useful from this paper. If you do use oil analysis, it might even help you interpret what the data is telling you about the fluid you tested, assuming you don't have a professional tribologist to interpret it for you.

A couple of things to consider while reading it is that the S2000 does have a transmission oil pump, and our differential holds a very small quantity of fluid (0.81 qts total).

Also, this paper was written in 2006, so some fluids have improved/changed, but not much.
http://www.fluidrx.biz/store/pdf/Nor...Car_Fluids.pdf

redlineracing

I agree that oils have gotten better over the years ,but it is my theory( and it's just a theory) that cars are harder on lubs than they were some years ago.We have smaller engines with higher HP & TQ and we are spinning them higher than we were in the past.

My theory is that oils are cheap and engines,trans & diffs are not.So what if I don't get every mile out of an oil & filter.They are recycled and that's a good thing.I still change the oil & filter in all my cars every 4-5 and trans & lube every 15k or 1 year,whichever comes first.

As always,results & opinions differ.

\rlr
carolina

dwight

I haven't read it yet, but I do appreciate technical information like this.

SpitfireS

Thanks for posting INDYMAC
But.. (I'm sorry, I have a "but").. where are the results?
The blue underlined text (assuming they are links to results) in the appendix don't work here - are they supposed to?

All cars are equal but some are just more equal than others
Some cars are harder on oil than others.
If you take certain German designed V10's, that produce a fair amount of HP per cylinder, you will see the connecting rod's big ends thicker oil to survive.
Is this a bad design?
IMO its part of the design, part of decision using a V10, where 2 pistons share a big end pin.
Those pins only takes so much, and thicker oil (higher HTHS) would keep parts apart longer.

In our little four banger this is not the case.
Every piston has its own big end pin.
Does this mean the design is better? (Hell YES!.. haha!)
Well.. I no, its just how 4 bangers are.
But revs actually generate oil pressure in the journals, so more revs = more pressure = more ability to keep parts apart.
That's why the F20 will run forever on a 30 weight, producing a pretty good specific output.
(so will F22's and probably every Honda engine)
Would Honda be able to design an off the shelf & long lasting V10 revving to 9k using a 30 weight?
Maybe not, it may be the nature of the beast.
If there is one thing to wish for it is Honda building an inline 6, 2,5-3.0l, revving to 10K, an off the shelf, (semi) mass produced engine like the F20.
To show certain German car manufacturers How Its Done

For the rest I fully agree with one of the statements made in the paper:
Talking about oil and oil change intervals is on par with talking about politics, religion and all the other personal preferences.

One other thing: Amsoil, as an oil manufacturer, does actually (up to a point) recommends long OCI's
As if they are not trying to sell by default.

BirdShot

I have to read this stuff for work and you guys are reading it in your spare time, ha!

Seriously though, it is fascinating to learn about. Noria's machinerylubrication.com has some great articles and more than a few of them have been written by co-workers of mine.

INDYMAC

Does Polaris Labs use similar criteria BirdShot? Or is it significantly different? The Noria criteria is pretty conservative, except for Fuel%. That's pretty liberal IMO. No reference to oxidation is conspicuously absent too.

I personally like to use the TBN/TAN crossover point on PCMO, and when TAN doubles its baseline value for HDEO.

I never had a good handle on gear oil condemnation, so I guess I'll use Noria recommendations as a start.

BirdShot

We have a similar general criteria that applies to samples that we get limited information on. The more details we have about a particular component the better. Our "library" of virgin samples is massive to say the least. Along with that if we know manufacturer, model, capacity, size etc, we can get VERY specific with analysis and general rules don't necessarily apply.

Fuel for instance, there are many Diesel engine applications that 5% would only be considered moderate. In a Gas engine that would generally be considered severe.

BirdShot

You would be amazed how many people blow right past the crossover point and deplete their TBN into nearly nothing...and many get away with it with no noticeable increase in wear.

For geared components it may sound strange but many times gear metal itself reaches unacceptable levels (enough to warrant a change) before oxidation reaches it's limits.

INDYMAC

Great stuff BirdShot, but don't stop now!!!



Thanks!

BirdShot

You guys know your stuff, I have been impressed and have even learned a thing or two.

We need our own sub-forum...