Disassemble QSM11 to fit in to boat – then reassemble

[Ed Fang]

In the early stages of researching to potentially repower my 6v92/550 powered flybridge express. Currently an ideal time to explore since my DD need to be overhauled. This would be an inframe overhaul. but doing research and due diligence on a Cummins QSM11/630 potential overhaul.

The engine can not be “dropped in” as the clearances in to the cabin and then the below engine room just doesnt have the clearance. So whatever happens, it has to be kind of disassembled and reassembled to get in to place. Obviously engine mounts, mating transmissions, exhaust elbows, electrical have to be handled by the techs. But just wondering – how much work is there to disassemble and re-assemble the Cummins QSM 11 inside the engine room. This sounds like an entire disassembly, check and re-assembly – like doing an overhaul to get it in to place. Or is is simpler to move in to place than that ? Thanks

Topic

[Ed Fang]

Rob. Thanks for the link. I literally found those last night and have already printed them out. Looks like the Cummins is 23 in longer than the 6v92. But in reality It’s probably 13in as the last part is what sticks out from the exhaust blower over the transmission which isn’t a big deal. It is about the same width and a few inches shorter in Height.

I got the engine block length of 37in but couldn’t get more accurate measurements I’d the width and height.

Currently measuring the centerline of the engine and it’s height off the bottom to align and see fit with the current Detroit. Determining the stringer that the Detroit sits on one side and how far down into that trough the Cummins fits.

[Ed Fang]

Sorry. I should provide more details. I read somewhere (boat diesel ??) that the qsc was a better fit for lighter applications – which was why I was turned toward the qsm. The boat is 50ft and 44k pounds. Which is why I gravitated toward the torqier engine vs the qsc. I should consider the qsc since it’s certainly more economical if that’s a better fit. Especially since I am looking at hundreds of hours per year vs thousands. But would love feedback on reasoning and recommendation.

Regardless of which one – looks like the cummins are more sensitive to fuel so will have to upgrade my racors to the tony seaboard fuel filters 🙂

[Rob Schepis]

QSM11 Dimensional Drawings

Ed,
Scroll down on this page:
https://www.sbmar.com/cummins-engine-drawings/

[Ed Fang]

Tony -thanks for the response. I imagine that getting it down to the engine block is the desired goal and no further as the work at that point might exceed the worth. Talking to the yard – they don’t believe getting the block in will be an issue. I didn’t consider coming in from the window which will be more than enough space. They did – which is why the professionals are professionals. Lol. They also said getting down beneath the floor to the engine room isn’t an Issue as the floor is designed to come up. So it’ll just go to tbe point of removing the hanger ons. Lol.

You would t happen to know what the engine block size without the hanger ons would be ? He said they would make a wood mock up and take it through to confirm no issues.

You bring up an interesting point/option on the QSC. I’m just more used to the lower rpm engines (2100rpm wise) with Detroit’s etc.i just gravitated away from the higher spinning lower displacement Cummins. Can you elaborate as to why the qsc might be a better choice for a 6v92 repower replacement than a qsm ? The qsm and 6v92 seem to be about similar sizes and both seem to be paired to ZF transmissions quite frequently. My ZF is a 320A1 though the qsm seems to be paired with the 325 more frequently.

But I would love to know why one would be a better match than another. Thank you.

[Tony Athens]

Stripping down a new engine

Removing “hang-on’s” from a QSM or any Cummins engine is not that tough for any 1st class hands-on owner…. “Hang-on’s” are referring the Heat exchangers, aftercoolers , alternators, starters , things outside the base engine.. Going past that?———–Never a recommended way to get any engine “thru the door”..

You might look at a QSC 600–Set up right, IMO, you’d be happier overall than with a QSM11 if your boat was build around a 6V-92..

Tony

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Ed Fang

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