Excellent data point. I wonder if it is reasonable to conclude that the babbit material in the sample can be conclusivly traced to the extended drain interval.

For additional data points, I've been doing oil analysis in my aircraft engines for several years. By nature of their application, they are all run at high power, full throttle95% of the time and most have only filter screens to trap particles. Normal drain intervals are 50 hours. Wear metals come and go with each sample. One sample will show high readings for valve guide metals, another will show a chrome spike (rings), while still another might show elevated babbit material readings. Mechanics will not conclude a pattern is developing until 2 consecutive samples show elevated levels and/or the filter screen contains enough visible metal to cover your pinky nail when cleaned.

On a microscopic level, particles in the oil must be larger than the thickness of the oil film in any given location (main mearing journals, valve guides, cam lobes, etc) for them to be able to do any scoring or cause increased wear. As a result, oil filter media is generally designed to trap virtually all of the particles larger than say 1/2 the thickness of the thinnest oil film to be found anywhere in the engine (usually on the valve lifters or rod bearings under heavy load).

Most engine damage and unexpected wear can be traced to pitting of wear surfaces from corrosive chemicals or long periods of not running the engine, which then suffer further damage as the oil film is broken slightly over the pits and metal-to-metal contact starts to occur.That definitely validates the need to keep up with oil changes, purely from a chemical buildup standpoint. As long as the filter is not clogged and bypassing itself, and is a good quality filter, the risk of damage from particulates should be very low. In my humblest of opinions, you would need to repeat your tests over several similar time intervals for the data to support any conclusions.

Thanks for sharing...good stuff.

Cheers,
Dave

 

I agree with repeating the tests. I just started to see for myself. I was going to extend out, and was told not to by several others on here who have not spoken out yet. I just did the tests for myself, had poor results, and went with the advice I was given. Good enough for me...I am not into R&D on these things, just want to know formyself and share with others what I have already found....

 

Hats off to you for taking the initiative todo the test in the first place. I have a hard time believing that you'renot interested in the R&D angle. Thefact you performed the testat alltells me you were trying to get at the right answers...a definite R&D activity.

I have no excuse...I'm just a geekwho loves to find stuff out, just because.

Dave

 

Itll help you find leaks in your exhaust too, I had white smoke coming out of my passenger exhaustmanifold to catalic converter conection. Thought I had blown something important until I popped the hood and saw where the smoke was coming from.