Ocean guardian bearing failure

I doubt an oil mist detector would have helped in this case. I think the flammable oil mist was created by the superheated part going through the block. Most oil mist sensors are inside the crankcase.

They did a fairly good job in the response from what I can read. A fast response with a handheld might have made it a smaller incident but that’s Monday Morning Quarterback stuff. They didn’t dilly dally about pulling the fixed system. Could have been much worse if they did.

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It sounds like there’s some guys in this thread with Cat experience so I’m curious about something.

Is it not standard practice after an overhaul to run the engine unloaded for short periods (say, 1, then 3, then 5 mins), stopping the engine between those runs, opening all the inspection doors, and using a laser temp gun on all the bearings? That’s what I’ve observed overhaul teams do on OSG ships and it seems like it would have caught the problem in this incident before it became an incident.

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I’m more surprised they didn’t plastigauge the bearings, or at least mic up the journals.

This is correct. Unloaded, partial load and full load runs of various lengths. Basically a full day of testing and checking bearing temps to ensure all is well.

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Not necessarily. NC does a lot of in frames and that adds a lot of time. Cutting open an oil filter and checking for unusual amount of bearing material is more common in my experience.

just read the report again. this was a top end overhaul, pistons rods and rod bearings. report says it was a main bearing failure which caused the adjacent rod bearing to fail. this does not make sense to me?
maybe i missed something but you would have to raise the engine up to remove the main bearings.it is quite unusual to have a main bearing failure but quite common to have a rod bearing failure and the crank journal machined with oversized bearing added. a top end overhaul is pistons and heads and typically doesn’t include the main bearings.
in another paragraph it says that the main bearings were removed and examined.
there is a lot of double talk here not surprising if you have ever worked up in Seattle.
it appears that the NTSB was Bambozzled

It was a top end overhaul, but the report states they removed one single main bearing for inspection. This is pretty common on overhauls I’ve done. You choose one main bearing as a representative health check.

It also said their policy was to replace any bearing inspected with a new one, which I’ve see vary by manufacturer and technician whether they replace or reuse. Where they screwed up was not checking the part number on the bearing shell they removed, which seems a crazy oversight, and making the assumption that since the con-rod journals were normal size that so should the mains.

I’m curious about this statement:

The Ocean Guardian’s local service managers and technicians stated that their normal practice when machining main bearing journals of a crankshaft was to also machine the connecting rod bearing journals throughout the engine at the same time, and vice versa when machining the connecting rod bearing journal surfaces.

I’ve only experienced an in-situ machining of a con-rod journal so can’t imagine doing all of the journals just because you are doing one. Is this common practice for engines where you can pull the crankshaft? To just go ahead and do all of the journals? Is that sort of “since it’s here…” and just to ensure uniform bearing shell sizes?

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A 35xx crank is probably going to the shop to get ground down instead of doing in place. Who knows what really happens or how they handle it.

Ya’ll must throw out your “marine engineering” thinking cap because 35xx engines are found just as much (if not more) on land than sea. It’s a bulldozer/genset/locomotive/etc engine. And thus the maintenance mentality often reinfects that.

You don’t roll the crank out when you do an in frame top end rebuilt it’s just like a pack change on an EMD
Pistons sleeves and bearings
It IS common to machine one bad bearing journal only and fit with an oversized bearing
I think what happed hear was
They threw the old bearing in a box during the removals and didn’t look at the size stamped on the remains bed bearings

Your link goes to the Ocean Guardian.

I believe they were shaft driven direct to z drives no reduction gear needed so you would need the high speed. I was part of a change over on a conventional tug to rolls Royce z drives. Engines were changed from 16 645’s EMD’s to high speed cats direct to the drives through carbon fiber shafts

I agree, at least that’s what a thought I stated but tell me how can you examine the lower main bearing shell without lifting the crank shaft?or do you just look at the top shell?

My mistake bottom main bearing removal not the top

For bigger engines anyway for the main bearing you unbolt/drop the bottom half of the bearing housing down to view the lower bearing shell. For the upper bearing shell, typically there is a curved tool slightly thinner than the bearing shell, with a pin that fits into the oil passage bore on the journal. You insert the tool and then roll the crank and it pushes/rotates out the upper shell.

AH! Thanks

One rolls out the other shell of the bearing. It’s not hard, youtube it.

The quoted text is from the Ocean Guardian report, the link is in the second post of this thread.

“Caterpillar original equipment manufacturer replacement bearings were not available for 85 days, so aftermarket bearings were purchased, delivered 2 weeks later, and installed.”

Seriously ?