Originally Posted by claluja
Any iron particles that reach the combustion chamber in the oil within which they are suspended are going out the tailpipe. No reasonable dispute there.
I would reasonably agree with this.
Any iron particles that leak out of the vehicle in the oil within which they are suspended are exiting the vehicle. No reasonable dispute there.
I would reasonably agree with this.
The iron particles in the oil measured by Polaris are smaller than both ring gaps and ring clearances. Its reasonable to assume that the vast majority of any particles over 10 or 15 microns will have been caught by the oil filter. No reasonable dispute there.
I would reasonably agree with this.
OP lost eight (8) quarts of oil. That's a lot (there must be some pretty big gaps somewhere!). No dispute there.
I would reasonably agree with this.
How can anyone seriously dispute A-Harman's calculation? Answer: can't be reasonably disputed. Any good engineer will calculate the worst-case scenario, because that is the most important number. That's what the OP did, and that's certainly what I would do. I want those guys designing bridges, cars, boats, and skyscrapers.
But are we assuming that the routes of exit (exhaust, or external leaks) are the ONLY means of oil volume exit?
As we know, lubes are volatile and we score them on a NOACK scale. Lube volume loss due to evaporation is to be accounted for also, right?
Does the evap portion of the volume loss carry 100% of it's solids out? Or maybe none of them? Or some portion of them?
Has anyone ever used a "catch-can" for the PCV and then taken that oil collected and had it analyzed? Can we quantify what remains in the vapor condensed lube in terms of elements? What's the ppm of metals and additive elements of the remainder? Even if we did do a UOA on the catch can contents, how do we really know if 100% of the vapors are condensed, or only a portion of them? Do we still burn "some" portion that escapes even the catch can? And if so, what portion of the vapors moving past the catch can have elemental wear particles?
Further, if we presume for a moment that 100% of what leaves a system (regardless of the method) carries with it 100% of it's elemental contamination and additives, then why are we adjusting the formula? In a manner, you're making my argument for me, I believe. Here's why ....
If we take into account that you and Charlie believe that 100% of the lost volume essentially carries out 100% of it's encapsulated holdings, then what remains must be no more or less contaminated than what left. Given that wear rates are reasonably steady (past 3k miles) in OCIs, all the way out to 15k miles, then we can essentially say that what goes "in" the oil in terms of wear metals is a constant, steady input. For every 1k miles, you'll get "X.y" ppm of Fe, Cu, etc. At any given time in the life of the sump, let's say you have drips coming out of a seal. That drip would be no more or less laden with wear metals that what remains in the sump. It's not like leaks are going to preference metals for exit. What leaves a system (via leaks or exhaust) is very likely to be extremely close, essentially identical, to what remains in the sump in terms of concentration.
And if there's some major loss of fluid, two things are happening; you're adding more lube that's (reasonably) clean with no contamination to speak of, and you're loosing lube that is contaminated.
So if the lost volume takes with it 100% of your elements it's holds in suspension, and the incoming lube carries in nothing with it in terms of wear metals, then why would the current sump volume at any given time not represent a reasonably accurate concentration irrespective of the volume added???
In short, what leave the system via different routes should carry out "X" ppm of Fe, "Y"ppm of Cu, "Z" ppm of Al .... etcetera. And that loss would represent what was "current" at the time of loss, right?
And, what remains in the system would continue to be contaminated with wear metals at the same rate as what left.
- If we were to allow a sump to drop 30% below it's marked level, then do a massive top off, and then take a UOA immediately 5 miles afterward, I'd have to agree that there's some error being induced because we've diluted the oil and taken an immediate measurement for such a large volume change.
- If we only allow a sump that holds 12 quarts to drop perhaps a quart and then get topped off (only about 8% loss), and then we top off keeping the loss to around 8% or so, AND we take a UOA perhaps 1k or 2k miles into the refreshed top-off, then it's reasonable to think we've allowed the system to normalize again; the input of wear metals has reasonably been allowed to stabilize. AND, since 8% loss is well within the NOACK score of many lubes, it's also reasonable to think that the oil loss may (not will as an assurance, but "may" as a possibility) be leaving some manner of metals behind (to a degree that I think none of us have data for).
What we know easily is how much lube it lost.
What we don't know is the manner of it's loss (leaks, burning in combustion, evap) and how much is carried out via these methods.
I would agree that external leaks and burning are likely going to take a large portion of the holdings.
But we cannot ignore loss due to vapors, and we have no data to know how much of the metals are being carried out.
Further, if what is being lost has 100% of it's wear metals going out with the host lube, then what remains should be reasonably representative of the "as current" contamination concentration, (as long as you don't do a massive sump refill and then immediately UOA; that would distort the concentrations).
We know from UOA data that wear rates are actually very consistent, barring any catastrophic event occurring. We can see engines that don't have much lube volume loss exhibit very consistent wear rates after the first few thousand miles after an OCI. Typically these rates only vary by a few tenths of ppm. Very consistent wear. And so, even if we have an engine that sees large volume loss (and subsequent make-up), there's no reason to think the wear rate of the engine changes substantially. We could debate the merit of the TCB being altered by the fresh detergents, but again, there's no study data that addresses PARTIAL OCI volume shifts, and it would be further complicated by the topic of what would be "residual" from a previous OCI ... Into the weeds we go.
What we can accept is that the engine will wear at a fairly steady rate. So the make-up oil, if replace at fairly frequent intervals, in small volumes, will not cause a condition to greatly alter the "as current" contamination concentration value.
So again I'm asking why you all are trying to adjust a mathematical formula for a condition that does not have proven data as to where ALL the wear metals go (does the evap carry or drop elements?), and the make up volume carries in nothing to the equation.