> I know truckers that have over > 150 K on a single oil change, and one in particular that not long ago had > his engine torn down at 409K, by Cummins. After inspecting the parts, > they > put the engine back together without replacing anything except seals and > gaskets. Everything was within "new" specs. This particular engine had > had > only one change in 409K. I believe the filters were replaced every 10K. > Keep a couple of things in mind:
Truck engines hold LOTS of oil, like on the order of 15 GALLONS Truckers add oil by the gallon, not the quart (or pint). Trucks rack up mileage pretty fast, like 100K or more per year. Trucks have huge filters, including bypass filters that can take out particles that are orders of magnititude smaller than a screen or even a Champion full flow filter can trap. Diesel fuel has NO lead. Truck engines have huge cooling systems. I've pulled apart engines that have been sitting for years, and there's still plenty of oil on the crank bearings. Aircraft cams are somewhat vulnerable to this problem, especially brand L, where the cams are in the upper part of the case, but I feel the real issue is corrosion protection. And there is anecdotal evidence that straight weight oils are best for keeping cams, lifters and steel cylinders from corroding. Years ago reusing cranks, cams and lifters at overhaul was commonplace. Today more likely than not they'll need to be ground. Now granted, most of these parts are 25 years older than they were back then, but still, one of the things that changed about the same time is oil formulation. back then 100 AD oil was pretty exotic. Now we've got 15w50 semi-synthetic stuff with Lycoming approved additives. Sure there are things about it that are measureably better, but... Of course if you fly it once or twice a week.... Your mileage may vary Thanks for listening. John
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