The point I am seeing made here is bearing gap seems to stay lubricated and isn't any real concern long term.
That being said, in the import cars in my neighborhood that I have witnessed go from new to burning oil and smoking because of quick drive offs with no warmup has to be valve stem wear. This does take over five years and longer but I see it happen. The valve stem wear was what I suspected all along and these engines are aluminum. Our boat engines are much better made.
What about oil consumption in the firetrucks mentioned? Did you know about the oil consumption or did someone else maintain the trucks?
Art, to be on record. I thought that marina owner was like mine. A guy that really doesn't go down on the docks and gets involved. Instead he sits in his office and goes by hearsay or whoever comes in to visit.
In my marina there was a boat that sat for 17 years and was full of diesel. He started it and left for Sitka, Alaska. He did go do a haul out first and change oil. A friend of mine drove the boat to the haulout docks. The diesel was still good.
Oil was checked daily at shift change and if needed was topped off, I don't recall ever adding any unless trucked was worked hard the prior shift.
We did not maintain them but were the folks that wrote up dings for maintenance to fix. I recall the motors being mostly bulletproof, hydro/water systems not so much.
Today's small car engines are wound tight and light, EPA and cost savings along with light weight has made them toss away engines.
Many have weak low friction valve systems and only 2 rings per high revving pistons and barely able cooling systems, not the stuff of long life.
If not for the improvements in oil these engines would be dead at 50-75 thousand miles. Would love to see one run on 1950's motor oil.
The above reasons along with morons not understanding how and why to maintain them and not wanting to spend the money on a car that they are going to trade in 3 years anyway is why so many are burning oil and trashed so young in their pitiful life.
We live in a disposable era, heck we replace cell phones every year or two, the TV may last 4 years and no thought is given to repair any more.
Sorry , putting this away now.....