I take a sample of oil just before mine is drained every two years, this to me will give me the best type of sampling.PDJ wrote: ↑Tue Mar 12, 2019 10:22 pmI am not convinced that oil sampling is that reliable for predicting a rod failure.
I am an engineering technician and worked on CCGT and CHP plants for around 15 years plus steel works, paper mills, large NH3 fridge plants (39ton 40 would have been COMAH) and food processing and packaging equipment. Built a Westfield and a 255BHP Duratec to go in it.
When I have done oil conditioning training (with Castrol) it has been for large volume oil systems so the cost is large to change the oil, but the principles have got to be the same, the thing that came round time and time again was a snap shot sample has little value, the condition has to be trended, over time to see a change.
So if you sampled a Gas Turbine oil every week or month or hour run and plotted the results you would see an increase in the white metal content as PPM and as this increased you would note that the main bearings are wearing or the thrust pads as this is where the white metal is in the ones I worked on. This would then allow engineers and accountants to plan to change the oil/overhaul the turbine to prevent a failure.
So in a car engine to see a trend you would need to sample as soon as you change the oil to get a base line/datum then re sample several time during the life of the oil before you change the oil.
You would also need to know what and where the deferent materials are in the engine that the oil passes by so to try and identify where the particles are from that may show up in an oil sample analysis.
Changing the oil will as I see it re set the datum as you have flushed away the suspended particles in the old oil. and then you would get a much better result if tested after an oil change.
This is just my thought from my experience and I have no real alternative for checking other than a physical on ie. remove and inspect, by which time you may as well replace them on a time/mileage basis.
Also so I have no real answer for the OP with regards as what to do, other than I will follow the thread as I am looking at buying a Z4M or a 3.0si
Hope the above ramblings make sense (not a typist)
and will generate a pattern.
I don’t think anybody would take one sample and make a decision on just that.