Vibration in 8.3 540 QSC

[Ron Carter]

I have a single 2006 QSC 8.3 540 hp with 1400 hours. I normally cruise at 1600 rpms. As was coming into a marina in a long channel I noticed at lower rpms…1000-1200… enough vibration to make the drinking water in my glass shake. Speed back up to 1600 and all is smooth again. When I docked I noticed a more than normal vibration at idle and looked at the tack which read 600 rpms. I think it used to read 650 at idle.

Any idea what is going on?

Topic

[Gene Fuller]

The OP sold that boat a couple of years ago, and he may not be active on the forum. In any case, I believe the concept is that any “dirt” floating around in the engine room will show up as soil on the pure white cup.

[John Muldoon]

What does the coffee cup do?

[Tony Athens]

Am I really that bad? Yes, I can get pretty short at times what someone asks a very answerable question and I answer him, but he doesn’t like that answer and it goes on from there..

Oh well, sometimes it’s either my way of the highway, or don’t ask……….. But at least it’s backed up with long term successful experiences & real field use and not with some school book who’s author writes about things he never really “touched” or went there , and most is based on screwed perceptions….

Tony

[Rob Schepis]

Tony Athens wrote:

I can handle a tad of one-on-one with your mechanic.

Tony

But can the mechanic handle it with Tony?!!

[Tony Athens]

Slot grinding–That will depend on if you have a clearance issues to make all of the isolators clear any contact with bracket surfaces where they so not touch ( like in the one pic I posted)..

I can handle a tad of one-on-one with your mechanic.

Tony

[Ron Carter]

I’ll talk to my mechanic who meets your physical and mental qualifications. He is young, resourceful, talented and very strong.

Where would the slot grinding possibly need doing?

If we get the parts from you would you be available for a phone call with him?

Is this the best Tony’s Tip for the job?

Isolator Mounting & Parallelism

[Tony Athens]

Using a young, thin, strong, motivated, and knowledgeable mechanic with the right tools, i’d figure 2 days on the boat to do it 100% RIGHT.. Not a fun job, plus he may have to do some slot grinding to get it right..

Cost for the right mounts is $660 for a set of 4 from us..

Tony

[Ron Carter]

Thanks for taking the time to look at this.

What is your estimate of the time in hours to replace all of the isolator/mounts? Would you have the parts? If so, how much?

Although the vibration is not that bad…and I know where it is rpm wise…I am the type to fix it right.

Ron

[Tony Athens]

Look closely at that attached pic.. I’d guess this is part of your issues.. You could easily have metal to metal contact under some conditions between some rigid bracket on the engine or GEAR ( in this case) and the isolator housing..

Plus, many of your isolators have had copious amounts of salt water dripped of them over time getting into the mount housing and the rubber inserts making their dampening or linear vibration absorption capabilities much diminished.

Overall, your isolator mount installation has left much to be desired.. If you want to make it right, it’s going to take a lot more than a wire brush..

Broken welds on the exhaust at 1400 hours or less……..Only one thing –poor design and or fabrication .. If you post some good pics of all, I may see where the issues are..

Tony

[Ron Carter]

Continued.

[Ron Carter]

Tony,

I am going to have to get a person smaller and younger than me to take the pictures. All I accomplished today was skinned knees, leg cramps and sweat dripping on my camera. The way the stringers are oriented made taking pictures very difficult. I will send some better ones when I can. I did learn that I need to get someone down there with a wire brush to get rid of the rust.

[Tony Athens]

Ron,

Your pics are good, but they DO NOT show what is needed for me to try and see if this is a “Mounting Issue” ( that is what I suspect at this time)…

Study the attached link…

Vibration Isolator & Engine Mount Views

This is what I need. Yes, this is time consuming, but this is what has to be done..

I need to “see” these views of each mount– all 8 of the meaning 16 pics in all.. If I was on your boat looking for the issue you have, then this is the 1st thing I would look at..

You put in your time and I will put mine in–Sounds like a fair trade to me..

Tony

[Ron Carter]

Tony,

The aftercooler was removed from the boat. both sides cleaned, and put back together with lots of grease. I would guess it is pretty close to the protocol you state here but I have not asked him if he is specifically aware of your method.

On Friday I ran the boat home at mostly 1600 rpms for four hours. There is no vibration at 1600 or at 2590 which is WOT with our current load of my wife’s stuff and half fuel and water….and a diver cleaned but two old bottom job. Smooth as silk at those rpms. The vibrations I have are not major but I can feel them and see the ripples in my drinking water. These rpms are 1200-1400 and around 1800. No significant shake at idle.

Here are some more pictures. i wish knew why the elbow weld broke.

Thanks

Ron

[Tony Athens]

Ron,

Yes, you need to get down there in take some real good pics showing everything..

You have a 1st generation early Mercury/Cummins “Dieselview” Display.. Considering the era of the engine, this is the best they could offer, so you are fine as long as it is working/readable…

I cannot tell much about the crack .. Be sure I “see” the entire exhaust system.

Ask your mechanic if the aftercooler was removed from the engine, completely disassembled on the bench, and then cleaned ( both the air & seawater side) and re-assembled put our protocol..

Tony

[Ron Carter]

Thanks Tony,

I am sending some information here and will get the rest when I get to the boat.

It is a 2006 Nordic Tug 42′. I have only had the boat for a year. The last owner only had it a year too and had to sell because of illness. It was a local boat and the mechanic that I have used for years was the seller’s mechanic also. That gave me a good feeling for it.

Right before I bought it “our” mechanic removed the entire cooling system and cleaned it properly. It was not in bad shape and no overheating had been experienced. So in marine years the cooling system is starting year two. He also installed a new dripless packing gland and aligned the engine.

About two months ago the exhaust elbow cracked a weld resulting in an exhaust leak that caused a power loss. My mechanic cleaned the air sep and repaired the elbow. Picture below. This may have been caused by vibration or have been a bad weld from the beginning. I have run the boat about 10 hours since the fix with no new leaks. Except for this boat I have kept a styrofoam coffee cup in the engine room for early warning of exhaust leaks. One is there now. It is still white as snow.

More to come

Ron

[Tony Athens]

Ron,

You have a 10 year old boat and your post is missing much to really help you, even a little bit. The questions you ask may seem simple, but trust me, they are far from that………..We want to help, but we need much more. This will be a basic start to sort this out………

#1—————-Let’s see really good pics of your engine as installed in the boat ( concentrate on the isolator mounts , turbo and and exhaust) , plus a picture of the of the boat itself.. It would really be nice to “actually “see” what we may be helping you with..

#2———————Tell us your maintenance history over the 10 years of “Marine Age” that applicable to your engines & boat……………. I want to know EVERYTHING for DAY 1, as you know it , from the day the engine saw “saltwater” in its veins……..

#3—————–Factory default idle for your engine is 600 RPM after a few seconds after you back down from anything higher RPM above 1000.. So that is GOOD..

#4—————–Post a picture of you helm station so I can see what instrumentation you have.. I need to be sure you are not driving “blind”..

Tony

[Author]

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