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Flatwrench

Hello, First thank you for the invite to the forums. I appreciate being able to post and ask questions.

I have x15 efficiency series cm2350 with 500hp and 1650ftlbs file flashed stock.

Mountain hauling and i25 at 75mph. Daily to denver and back home over the mountains. 9% grade. Engine made it to 10k hours 570k miles before taking number 6# ring....It was with optional range with no overheating logging but was towards higher end. I blame myself for not making it out fleet rotation and cleaning fins of the radiator. Maybe we could have prevented it.

All liners look like this except for number 6 with scoring.

We run more 450st and they are tanks....like 23k hrs and 600k miles with no blowby or very minor.....Champs. Almost 1mpg better fuel mileage on same run. Even the 565hp at 600k are holding well on no byblow.

Efficiency 500hp doesn't seem to be great match at this elevation from 10,000 to 5,000.

Question: Is it possible to turn the 4342 cpl down to 475 or 450? What are your guys thought on the liners?

It was a new driver to us that drove this truck for last year. It was full throttle or nothing.

Appreciate any thoughts. Engine has been rebuilt with Guideline on the forums with new radiator also. Just want to keep this purring best at possible like rest of the isx's in the fleet.

Thank you .

Rawze

one problem I see is that oil is absolutely nasty. If it broke a ring, its because it got sharp as razorblade due to all the soot packing.

== what is the fuel mielage, and what is the oil change interval?.

-- is there a bypass oil filter installed to keep the soot out of it?.

2 things to think about to prevent the same failure in the future.

mikkhh

75mph mountain hauling, full throttle or nothing.

Considering how it was used it lasted quite well.

The overhaul is done now with all OE parts? Liner heights are raised like they should to ensure longevity?

In what RPM range this engine spent most of its life?

How worn were other rings? Easy and fast check is to feeler gauge and fit ring in liner to see if there is any huge wear.

What actually happened? Had lots of blow by? Just oil consumption issues?

What oil grade was used? Expensive fully synthetic 5w30?