Originally Posted By: Trav
New engine measurements and wear limits from Honda FSM. Over 200K km all lubricated parts within new specs using Starrett micrometers (digital and analog).
This engine was owned by me from 0km brand new in crate motorcycle for over 12 years, run on one brand and weight oil except for the break in and Honda oil filters with the exception of a few aftermarket filters when OE was not available.
Engine was totally disassembled for a stretched cam chain, cylinder and pistons removed and cases split. The engine routinely saw 12,000 rpm and high sustained speeds.
What experts? I have SAE access. No dispute oil with few particles will result in less wear but the question is where do the particles come from?
How do you know the filters you used on that engine weren't pretty high efficiency? Any specified efficiency rating given for them?
Just because all the parts were still in FSM specs doesn't mean there wasn't some wear.
The most basic way to determine if a better filter would have made a difference in wear would to measure the wear rate in two separate engines with all conditions the same except for the filter. Tear each engine down and measure to 0.0001" accuracy, run the engines under the same exact conditions using yhe dame oil and maintenance schedule, then tear down and measure again to compare. Need a delta from the new measurements baseline. Just measuring and comparing to the wear-out spec range in the FSM doesn't actually tell you how much wear there was compared to the new engine baseline measurements. Way more sophisticated methods of measuring engine wear are discussed in SAE papers.
And yes, I agree that a bad air filter can really cause high wear rates, especially on valves, rings and cylinder walls. Engines with a good air filter still produce debris from combustion blow-by and from start-up wear, and from being ran when the oil film thickness breaks down for some reason and causes metal to metal contact wear. No oil prevents 100% separation of heavily loaded moving parts a 100% of the time.