How long to lay down anti-wear layer?

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So after you change your oil, how long does it take to lay down the protective layer? I am a little over 400 miles into my OCI with Honda Synthetic Blend 0w20. Not sure if highway or city driving effects the laying down of the anti-wear layer, but the majority of my trips are under 5 miles, with many being under 1 mile.
 
if your engine isnt brand new, I'd say it still has something going from previous fills.

Its more of an engine heat thing, than city or highway. The oil has to get up to full temp to activate all the additives.

To say it simply.
 
Originally Posted By: Shannow
How did you get the old one off ?


I have read on here that the new oil washes off the old AW layer and lays down its own. The thing is my engine RARELY gets to full operating temperature. I was able to get on the highway for 10 minutes this week..but thats a rare occurrence.
 
The Boron and Calcium assist right away.

The ZDDP and Moly become activated upon pressure and heat.

The first heating comes about by pressure as in, T is proportional to Pressure X Volume/k.

The following heat is generated by the combustion process and the conduction of heat from hot parts.
 
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Molakule, I differ on your first source of heat.

Oil's not a gas, and has no temperature rise on raising pressure...will be heating on the volume passing through a relief, just not the initial pressure raising.

Additionally, the viscous heat of cranks/pistons/cams etc. doing work on the oil is an additional source.

Edit...I forgot that the pressurised oil has to come out somewhere...molakule was right...
 
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Trying to keep it simple here guys.

Oil is not a gas but it is a substance whose temp rise can be calculated using any of the Virial Equations of State.

The "k" takes into account any of the constants or coefficients necessary for the Virial Equations of State.

Of course, one could take the Enthalpy equations with tables but that is about as complex as the Virial Equations.
 
Originally Posted By: JHZR2
Originally Posted By: Shannow
How did you get the old one off ?


Exactly.


Some of the old additives are still present but are degraded due to oxidation, heat, shearing, etc.
 
Originally Posted By: gregk24
The thing is my engine RARELY gets to full operating temperature. I was able to get on the highway for 10 minutes this week..but thats a rare occurrence.


Then you need lots of Moly, as it reduces friction (and wear at the same time) at a lower temperature than zddp. See page 20 of This Here Web Article Link
 
Originally Posted By: Trav
But the new oil isn't washing whatever is left away correct?


Correct. It is not acting as a light hydrocarbon solvent would.

The new oil, with its relatively more reactive detergent/dispersant package, is picking up contaminant precursers and suspending them.

The new AW additives are simply replenishing the old AW additives.
 
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Thanks for clarifying that Molakule. Someone posted a while ago that changing the oil more often is bad for this reason.
I figured new oil is always better than old.
 
Originally Posted By: MolaKule

Correct. It is not acting as a light hydrocarbon solvent would.

The new oil, with its relatively more reactive detergent/dispersant package, is picking up contaminant precursers and suspending them.

The new AW additives are simply replenishing the old AW additives.


MolaKule, this reminded me of something I wanted to ask you about that is related to the subject of this thread... What is your take on the whole "Can you change oil too soon?" debate?
Do 3k OCI's do more harm than good versus 5k OCI's?
 
The change the oil too often seems to have come from the Ford/Conoco study (mentioned heaps, got it's own thread once) which concluded that used oil provided greater wear protection than new...

Not an actual engine test, the test took used oil and did an (IIRC) pin on disk to measure wear (did have some radiological trace element testing to verify)...versus new oil.

Has been interpreted as more wear after an oil change, tribofilms are gone after an oil change, and stupidly (IMO), that the in service lubricants thinned down enough to protect better (in a pin/disk, after the paper clearly showed thickening).

Test did indicate that the additives are activiated by use, becoming more effecive (more varied species ???) but didn't say that the tribofilms were removed each oil change.

Has me (hack chemist) adding a little MoS2 with each oil change...Formerly used SxUp.
 
Originally Posted By: Triton_330
Originally Posted By: MolaKule

Correct. It is not acting as a light hydrocarbon solvent would.

The new oil, with its relatively more reactive detergent/dispersant package, is picking up contaminant precursers and suspending them.

The new AW additives are simply replenishing the old AW additives.


MolaKule, this reminded me of something I wanted to ask you about that is related to the subject of this thread... What is your take on the whole "Can you change oil too soon?" debate?
Do 3k OCI's do more harm than good versus 5k OCI's?



What Shannow said.

I was going to reference that study as well and say about the same thing.

Quote:
The new oil, with its relatively more reactive detergent/dispersant package, is picking up contaminant precursers and suspending them.

The new AW additives are simply replenishing the old AW additives.
 
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