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HotRod

I will snap a couple more pictures tomorrow, but this is a liner out of a dd15. The cylinder imbalance logic actually detected an imbalance in this cylinder. The marks do not make any sense. They go in the circular motion of the liner. Almost as if they were in there from the factory. After watching some videos of the assembly process it is hard to believe it would have come from that and passed tech inspection, but it does not make logical sense in my mind for the marks to have come while running. They are about 3 inches in total height, if the piston was at BDC, the marks would extend down to the piston skirt about 1 inch, and almost to the top of the piston but not above it. You can feel these grooves with your finger or fingernail, with a snap gauge the liner measure in spec and the same as cylinder #1. The failure was on #6 cylinder. No definitive damage to the piston, but there are 1 or 2 faint Mark's in the piston skirt similar but not the same as the liner. No more or less carbon deposits on this one than any other liners. No damage to rod or main bearings. Shiny metallic deposits was in the oil filter housing, but an oil sample said there was no evidence of high traces in oil pan. Not sure if the filter just did a great job or I'm losing my mind/overthinking this issue. The truck is a 2016 cascadia with about 580k mile on it, Pulls flatbeds out of Charleston sc to places all over us, so loads vary all the time. Let me know what you guys think. There is alot of knowledgeable people on here! Thank you for all you do!

tree98

Need some pics from a little further away to give some idea of what we're looking at.

HotRod

I realize now after looking at the post it turned the picture. I attached another picture the arrow indicating the up position, the red line is where the oil control ring or maybe the bottom of the piston crown sits on the liner at BDC. It is hard to get any further away due to taking the picture from the inside of the liner. I will try to get a few more better pictures tomorrow and post them as well.

HotRod

Here are 2 more pictures I got off another phone. I will take some more tomorrow.

Nilao

That's hard to say. I wouldn't that be a broken ring would notch the liner like that. Usually a up and down score....that would almost have to be a manufacturer defect.

Squish099

(03-11-2020 )Nilao Wrote: That's hard to say. I wouldn't that be a broken ring would notch the liner like that. Usually a up and down score....that would almost have to be a manufacturer defect.

That's what I was thinking. It's to symmetrical to be an accident. Almost looks like the cylinder hone at the factory had an accident, and the assembly tech said f' it.

HotRod

That is about the only logical explanation we could come up with as well! Figured I throw it out here and see if anyone has ever seen anything like it before, or had any other insite. If we do not conclude anything other than factory defect, we are going to send it in through our detroit dealer and see if they have anything to say about it.

schISM

I would say it would be impossible if that’s a factory defect but that’s exactly what it looks like. The cutting process involves separate boring bars, a rougher and a finisher. It looks to me like the rougher insert could have broken leaving too much material for the finisher causing it to “chatter” when it took its turn. If it had happened anytime after assembly those marks would be running parallel to the travel of the piston not horizontal.

Rawze

I do not think those marks themselves, if a manufacturing defect, would cause issues. Like mentioned though, QC at the engine plant had to be out for a lunch break on that one. I know that I would certainly not want that in my engine.

Curious though, why did the motor had to come apart?