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Old 28-01-2019, 15:37   #16
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Re: Shearing bolts on elastic coupling D2-55C

It's certainly possible that the torsional damper on the flywheel can make noise, especially at lower RPM when the power pulses are fewer and further apart, and the engine is running rougher, but I don't have any experience with the damper causing vibration. Of course, that doesn't mean it can't happen...


If you are experiencing bolt loosening on the engine flex isolators it may good to pull them and see if there is deterioration of the rubber. It shouldn't be too difficult to block up the front of the engine and slide the isolators out sideways. The engine is probably getting on to 15 years old now and the rubber parts don't last forever. Probably good to check the rubber mount on the saildrive as well, but that one isn't so easy. You can block the rear of the engine/saildrive up by inserting two pins( one on each side) in the 1/2" (12mm) holes in the engine mounting flange of the saildrive. Then insert wood blocks between the pin and the fiberglass engine bed to hold the engine/drive up. Then you can remove the saildrive support bracket and see the rubber element.

DougR
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Old 21-03-2019, 16:00   #17
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Re: Shearing bolts on elastic coupling D2-55C

Hi DougR, first of all, my apoligies, I was wrong on my engine type. It is a D2-55E which also explains, why the flywheel housing allows replacement op the damper plate while in place as you state above.

I have removed the saildrive in order to get changed the diapragm, and so I also could check the coupling. All bolts were fine and fixed, however I could see that the flexible coupling was touching the mounting plate for the saildrive. So there must be something wrong with it. I found some pictures on the internet, and I assume, that my coupling (the two plates) are too far apart from each other. I can also bend the two plates very easily and this must be the reason for those vibrations I hve realized.

I have not seen a new coupling, but looking at the pictures, it really looks like there is a problem. Any advise welcome. I was informed, that R&D in the UK should build more durable damper plates as they use nylon elements in it. But our lokal distributor says that they do not have a model for the 130S-B saildrive. In the brochure I can only see Volvo 110, 120, 140 saildrive either.

Any comments welcome what to do now. The new VP part is quite expensive. Is this really my problem on irritating vibrations? Does it look like at damper problem? Look at the distance between the black and light plate. I assume my space between those plates ist too big. The last picture I got from the internet to compare. If I press the two plates together, there is quite large "working space". This seems not normal. I have not seen a new one tough. Any experience welcome.
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Old 22-03-2019, 09:27   #18
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Re: Shearing bolts on elastic coupling D2-55C

There certainly appears to be contact between the damper and the saildrive mounting plate, where you have pointed out with the pen tip, as well as on the front of the saildrive bearing housing where there is rubbing close to the center of the damper.

It seems ( without having a damper in my hands) that the center portion of the damper, the dark colored part, is held in position by the four rubber elements in the center of the hub. These four elements are the softer of the rubber parts, designed to allow the damper to absorb torsional pulses at low rpm and low power levels. As the torque is increased they compress more and more until the four large pins are pressing against the harder rubber stops and that transmits the full engine torque.

If the soft rubber elements are damaged or worn it could allow the center section of the damper to move aft and contact the mounting plate or the saildrive itself. This could cause the noise and vibration that you are experiencing, but in all probability the only way to know for sure is to replace the damper.

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Old 25-03-2019, 00:27   #19
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Re: Shearing bolts on elastic coupling D2-55C

Hi DougR,

i have found the parts bulletin you mentioned in the beginning of this discussion, concerning the screw/spacer info where Volvo changed the thickness of the coupling mounts. In the bulletin are drawings and measurements of the new and old coupling ang by that I can for sure say that the coupling is way beyond the specifications. It should be 30,5mm thick and with +- 0,5 mm tolernce. But mine measures 32 mm and 33mm around it.


But the question is, why did it fail?

I had observed the following:
- previous owner told me, that he had hit something on the original prop and this caused the prop to be exchanged - I got the repaired one as spare.
- Second prop was sligtly out of balance on one blade so I have installed a brand new one last year which is fine now.

So, I assume those provocated the issue. With unbalance in the prop, there is a rattling in the saildrive and this could cause the coupling to walk.

I just want to check for the flywheel / gear alignment issue as well and would like to measure the screw holes as specified in the other service bulleting you mentioned. A VP dealer had checked drive and gear serials and there is no outstanding service issue, but just to be save I would like to check it as the flywheel housing does not fluctuate so good on the starbord side than on the port side. I could not find that bulletin on the internet.
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Old 23-04-2019, 08:17   #20
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Re: Shearing bolts on elastic coupling D2-55C

Does anyone have access to a D2-55 workshop manual?

Would like to know the torque of the 6 bolts to mount the coupling onto the flywheel.

Should loctite be used on the bolts ?
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Old 23-04-2019, 08:40   #21
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Re: Shearing bolts on elastic coupling D2-55C

The bolt torque for the elastic coupler fasteners is 22 Nm.

Clean the internal and external threads and use Blue loctite (non permanent).

DougR
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Old 23-04-2019, 10:04   #22
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Re: Shearing bolts on elastic coupling D2-55C

Thank you!
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Old 10-05-2019, 04:36   #23
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Re: Shearing bolts on elastic coupling D2-55C

Hi DourR. I have launched the boat today and all works fine after changing the flexcoupling. Sails much more smoothly with less vibrations. The only thing i notice is a little whining noise especially when slowing down which engaged gear. Then it keeps being there at around 1000 rpm. As soon as you put more load in the propeller or more / less rmp (idle) the noise is gone.

The boat had it as well before with the faulty flex coupling. But not so extreme. Any idea here?

Saildrive was also taken apart to change de rubber bellow. I used all shims where they have been before.

The noise is coming from gear/flywheel housing. It is only when engaged in gear.
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Old 28-09-2019, 12:54   #24
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Re: Shearing bolts on elastic coupling D2-55C

Hi DougR, the noise I described in my previous post is definetively related to the propeller. It is "singing" at around 1.000 rpm. So I will test another propeller in the next season as I was experimenting with a 1" smaller prop in diameter on this season.

But during the season I realized that there is still another "whining" noise in certain rpm. I wast first investigating the alternator belt or bearings as it sound like a whining bearing, but the noise is only under load with the gear engaged. In idle, there is no such noise.

Is there a possibility to upload or link a soundfile somehow?
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Old 02-10-2019, 07:49   #25
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Re: Shearing bolts on elastic coupling D2-55C

VP had some problems some time back with their fixed blade two and three blade aluminum saildrive props singing at various RPMs , and it was determined that the cause was related to the finishing process at the prop manufacturer.

It seems that the prop blade trailing edge was finished with a very fine radius, and during the priming and paint process this radius grew into a larger rounded profile as a result of paint buildup. During operation the water flowing off this trailing radius can sometimes get into a back and forth oscillation, much like the trailing end of a flag in the wind. It's this water oscillation that causes the prop blade to begin to vibrate and sing.

The cure is to change the profile of the trailing edge of the blade so that the oscillation doesn't begin. Attached is a sketch which shows the basic idea of material removal from the trailing edge of the blade. In my experience removing enough material along the length of the trailing edge to make the bevel about 1 to 1.5 mm wide works well. This is easily done on a belt sander with the prop hub laying on the sander table and carefully removing material to a pre marked line. Then repaint using care to avoid paint buildup.

Hope this is helpful. If you go online there is lots more info on singing props.

DougR
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