Scratch on piston liner

[Howe]

A friend of mine use motor oil that contain Boron Nitride. After the oil reach end of life, he change it with oil that contain Molybdenum Disulfide. Once again when the oil reach end of life, he drain it. Each time before pouring fresh motor oil, he inspects the piston liner, pistons and its rings. After he use oil with Molybdenum Disulfide he noticed that the liner heavily scratched.
Can anyone help with analysis, how this can happen? I really appreciate your help.

 

[RooflessVW]

Correlation ≠ causation.

 

[atikovi]

Each time before pouring fresh motor oil, he inspects the piston liner, pistons and its rings.

He takes the engine apart before every oil change?

 

[BigCahuna]

Is he confusing the cyl cross hatch on the liner, with being damaged ?.,,

 

[Kira]

My money's on fiberoptic borescope.

What does "heavily scratched" mean? Longitudinal scratches are they? Can he make out the original hatching?

Could he measure the scratches? Could the lighting change the appearance of any scratches?

 

[Cujet]

I deal with aircraft engine inspections all the time. As such, I'm very familiar with fiber optic and video scopes. It is very common to "see" things that simply are not problems. Especially with lower quality units.

Strong suggestion: Use an incandescent light source, not LED. One can easily solder a bi-pin "mini-maglite" light bulb to the end of two tiny wires and use the rest of the flashlight as the power source. Reason: LED light sources for video scopes really highlight discolorations, and not actual defects.

With all that in mind, the oil type or choice won't cause or result in cylinder scoring. Mechanical problems will.

 

[Bill_W]

Oops.

 

[Bill_W]

A friend of mine use motor oil that contain Boron Nitride. After the oil reach end of life, he change it with oil that contain Molybdenum Disulfide. Once again when the oil reach end of life, he drain it. Each time before pouring fresh motor oil, he inspects the piston liner, pistons and its rings. After he use oil with Molybdenum Disulfide he noticed that the liner heavily scratched.
Can anyone help with analysis, how this can happen? I really appreciate your help.

Notice he inspects the rings… Interesting. Seems another factor is involved, possibly dislodged carbon deposits? Maybe Boron Nitride leaves ash deposits in ring grooves that broke up with new oil.

 

[atikovi]

Notice he inspects the rings… Interesting.

Can see the rings even with the head off.

 

[Bill_W]

Can see the rings even with the head off.

He tears into the engine. But then it seems he would clean the carbon deposits off. Or since this is second hand info maybe he did not check the rings and just used a bore scope.

 

[Howe]

He takes the engine apart before every oil change?

His car I believe more than 10 years old, maybe he did that recently because he feel something is just not right

 

[Howe]

I think he experienced his car compression dropping, that's why he suspects scoring is the most possible cause. Could it be the amount of Boron or MoS2 is excessive?

 

[OVERKILL]

I think he experienced his car compression dropping, that's why he suspects scoring is the most possible cause. Could it be the amount of Boron or MoS2 is excessive?

It's far more likely that he has a compromised air intake tract and dirt has entered the chamber, causing the scoring.

 

[Jetronic]

Or there's no scoring at all, I've seen smears of oil that looked like scoring until touched/cleaned off.

MoS2 looks shiny, I'm sure it can play tricks on a borescope image.

 

[OVERKILL]

Or there's no scoring at all, I've seen smears of oil that looked like scoring until touched/cleaned off.

MoS2 looks shiny, I'm sure it can play tricks on a borescope image.

Also a possibility for sure.

 

[OHChevy3.0]

^^^ Had that happen a couple times using a Snap-on scope on Harleys. The glare makes it look like scoring until the head comes off. Then there is nothing abnormal found. Or only minor wear.

 

[kschachn]

A friend of mine use motor oil that contain Boron Nitride. After the oil reach end of life, he change it with oil that contain Molybdenum Disulfide. Once again when the oil reach end of life, he drain it. Each time before pouring fresh motor oil, he inspects the piston liner, pistons and its rings. After he use oil with Molybdenum Disulfide he noticed that the liner heavily scratched.
Can anyone help with analysis, how this can happen? I really appreciate your help.

This is a complete non-sequitur and is total nonsense.

It does go along with gravitational forces on pistons however. And you're other friend's thinking about 5% ester in motor oils.

 

[Howe]

maybe I got a quick judgement from my friend, got intrigue as well

This is a complete non-sequitur and is total nonsense.

It does go along with gravitational forces on pistons however. And you're other friend's thinking about 5% ester in motor oils.