Reduced engine wear from extended oil drain intervals due to film formation
 

My previous oil had a mix of MMO in it. But, I've been second guessing that move, because I wonder if a certain amount of varnish is actually a good thing. I say this because after adding MMO, my tappets became much cleaner, but I noticed that brown varnish was filling in the micro-scratches on the surface of the tappets and the cam lobes. So, it got me wondering whether motor oil forms certain films (which might include a certain amount of varnish) that help against metal-to-metal wear.

Does anyone have this article?

http://papers.sae.org/2007-01-4133/

"Engine oils are subjected to a series of industry standard engine dynamometer tests to measure their wear protection capability, sludge and varnish formation tendencies"

"...it was observed that engine oil samples collected from fleet vehicles after 12,000 mile drain interval showed 10-15 % lower friction and more importantly, an order of magnitude lower wear rate than those of fresh oils."

"It was also observed that the composition of the tribochemical films formed was quite different on the surface tested with the drain oils from those formed with fresh oils. The objective of this investigation is to demonstrate how the friction and wear performance changed with oil drain intervals."

It seems that tribochemical films (which I'm assuming possibly includes varnish films on surfaces) help protect against wear.

And, there's also these articles:

https://springerlink3.metapress.com/cont...pringerlink.com

http://onlinelibrary.wiley.com/doi/10.1002/ls.3010090402/abstract

Does anyone have copies of these articles? It seems MMO and other additives might remove antiwear films, but I'd like to read the articles for their conclusions....

What's an 'MMO'? I'm going on 8000 mies with the current oil in my M103. I'll change it at 10000. M1 15w50.

I'd be interested in knowing what kind of car you have because any engine with over-head cams, which has been the case with MBZ engines for at least the last 50 years, does not have tappets (cam lobe>rocker arm>valve stem).

Marvel Mystery Oil. I used to go between 8000-10000 intervals with M1 0W-40, but because I blew a cam oiler tube, and replacing the tube and the afflicted lifter didn't remove the ticking, so I've been going very frequent oil changes.

Btw, after such long intervals, when I disassembled the lifters, there was indeed a lot of carbon particles in the working chambers, even though the rest of the motor oil was fine (dark, but no crud).

For sure, we must be having a difference in terminology. Tappets are HLA's (hydraulic lash adjusters, also called cam followers), and the M119 has flat bucket tappets. Btw, in your example of the rocker arm design, it would be cam lobe > tappet > push rod > rocker arm > valve stem.

I am not reading this thread...
I am not reading this thread...

Must change oil every 3,000 miles or 3 months...
Must change oil every 3,000 miles or 3 months...

Don't get distracted...
Dont get distracted...

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:rolleyes:
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:)
:(
:o

Carefully crafted, but ya forgot an apostrophe on your last "Dont." :grim:

I'll stick with my 4-5k changes with synthetic on both of my vehicles. It has served me well so far....21k on the gasser, 96k on the diesel during my ownership.