QSM11 High Chromium in Oil Sample

[Curtis J McNamee]

I am looking at purchasing a 2002 Bayliner with Cummins QSM11 engines with 3900 hrs on them.

During the inspection, I had engine oil samples taken which have just over 250 hrs since last oil change. The oil used in the engines is Delo 400LE SAE 15W40.

The Chromium on the port engine came in at 7 ppm and the starboard engine 10 ppm, the report says all other levels were normal

I have attached the reports and looking for any input and suggestions.

Topic

[Fireisland1]

Something like this maybe

[Philip]

Curtis J McNamee wrote:

Hi Rob- Yes, we did a cold start, sea trial and oil samples were taken, the boat had almost full fuel…800 gals. I did look at the fuel burn as we moved up thru the power settings but did not record them. How does that effect what we are seeing in the oil sample results ?

If you are overpropped then your engine is working too hard (stressed) and that could explain wear metals in an oil sample.

It doesn’t sound like you have recorded rpm vs fuel burn data and max rpm data. I would highly suggest you get that before moving forward..

Phil

[Rob Schepis]

Chromium is a wear metal. Instantaneous fuel burn throughout the rpm range compared to the printed curve from Cummins will tell you how she’s propped and loaded (see section #2 in the second link). Was there not a surveyor or engine tech on board? If so, I would be really surprised if neither recorded the data from the displays…

https://www.sbmar.com/articles/engine-life-vs-engine-loading/

https://www.sbmar.com/articles/is-my-boat-over-propped/

[Curtis J McNamee]

Rob Schepis wrote:

Curtis J McNamee wrote:

not sure about the propping or how the engines have been run in the past.

You did a seatrial, no? You must have if oil samples were taken. With the boat as heavy as possible, you need to record the fuel burn at rpm increments throughout the rpm range from hull speed and beyond. And then go here:

https://www.sbmar.com/articles/propping-cummins-qsm11-to-prevent-exhaust-leaks/

Yes 250hrs is a bit stretched on the oil change interval. What oil filters are currently fitted?

Hi Rob- Yes, we did a cold start, sea trial and oil samples were taken, the boat had almost full fuel…800 gals. I did look at the fuel burn as we moved up thru the power settings but did not record them. How does that effect what we are seeing in the oil sample results ?

[Rob Schepis]

Curtis J McNamee wrote:

not sure about the propping or how the engines have been run in the past.

You did a seatrial, no? You must have if oil samples were taken. With the boat as heavy as possible, you need to record the fuel burn at rpm increments throughout the rpm range from hull speed and beyond. And then go here:
https://www.sbmar.com/articles/propping-cummins-qsm11-to-prevent-exhaust-leaks/

Yes 250hrs is a bit stretched on the oil change interval. What oil filters are currently fitted?

[Curtis J McNamee]

Rob Schepis wrote:

If all else was normal that one level alone does not appear to be alarming. Was a blow by test done? Cold start? How was she propped throughout the rpm ranges?

Hi Rob- Thanks for the input…I am having compression and blowby tests done next on these engines to see if we can find anything obvious.

Cold start and the lack of smoke are really good, not sure about the propping or how the engines have been run in the past.

What is the recommended interval for oil changes on these engines….seems like 250 hrs is excessive…

Curt

[Rob Schepis]

If all else was normal that one level alone does not appear to be alarming. Was a blow by test done? Cold start? How was she propped throughout the rpm ranges?

[Author]

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