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Drive line clatter?!


j04n

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Hello All, I have sought advice from Vetus, Aquadrive, Pythondrive and centa and only had a reply from Vetus so thought I would turn to you lovely people! 

 

From day one of owning a secondhand widebeam there has been an intermittent clatter from the driveline/ prop. I bit disconcerting initially but now just bloody irritating. Seems worse in shallow water but always there to one degree or another. Seems more like resonance than linked to actual rpm as comes and goes. 

 

After recently realigning the engine it is better but still there.

 

The boat is 57ft by 12ft with a draft of 2.5ft and a weight of circa 37 tonnes. The engine is a Shire 65, Yanmar 4TNV98, maximum 2600rpm, 69hp. The gearbox is a Newage PRM260D2.  
 
Attached pictures show the current setup. The engine is at the top of the engine mounts which I know is not ideal as this allows the engine to move excessively so was thinking about putting 15 or 20mm spacers in to allow for dropping the engine on the mounts. However, the engine exhaust is currently hard up against the floor of the wheelhouse soundproofing so I quite like the idea of an Aquadrive or Pythondrive which would allow me to drop the engine without fitting spacers. Although I do not have so much room as you can see attached.
 
Any suggestions/ advice would be very much appreciated?

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Edited by j04n
woops!
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To be honest this is a classic example of a more modern way of installing an engine and driveline in both widebeam and narrow boats. and has been going on for some years now. The engine space not being anywhere long enough to fit proper thrust block and double UJ final drive to compliment a rubber mounted engine,, all compromised by the want of a cabin as big and as long as possible instead,  giving many problems, extra maintenance expense and angquish to many owners. If it were mine with not enough room to install the above mentioned I would solid mount the engine and align it properly in orthodox old fashioned ''if you like'' marine engineering style, and have no more problems.  There will be a little extra vibrational noise, but be jaze, its worth it.

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i hear you but there is the small matter of the exhaust manifold being hard up against the floor soundproofing. 

I know it's impossible to precise but anyway of describing how much more vibration there's likely to be? are we talking teeth chattering uncontrollably, plates walking off shelves, or........? cheers 

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3 minutes ago, j04n said:

i hear you but there is the small matter of the exhaust manifold being hard up against the floor soundproofing. 

I know it's impossible to precise but anyway of describing how much more vibration there's likely to be? are we talking teeth chattering uncontrollably, plates walking off shelves, or........? cheers 

Perhaps you could make a bulge or extra sort of hollow seat on the floor so the manfold clears it. Like the power bulge on the bonnet of some muscle cars. :)  On a heavy widebeam boat extra vibration should be fairly minimal, a bit of a buzz really. :closedeyes:

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1 minute ago, j04n said:

lol! I take it when you mention solid mounting the engine you would still leave the flexible ish coupling in line? 

Oh yes.  In fact a more flexible one if pos. It will prevent some transmitted engine noise and also lessen the shock if the propeller clouts something solid. I take it that there is a bulkhead close up to the front of the engine so the engine can't be moved forward  by another foot or two to accomodate a twin UJ and thrust block  ie (Aquadrive or Python drive).

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it could be moved but maybe only 6 inches without re engineering the black water tank. i boxed the engine in with sound proofing but that can easily be moved. it is a poor layout as actually there is masses of space only taken up with fresh water tank, waste water tank and engine all in line. When actually tanks could have been mounted either side. Although that would limit access to engine i guess. 

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1 hour ago, j04n said:

Maybe, but would be surprised as reconditioned unit from RCR last year when I changed it from a D3. only done 100 hours. 

How do you recondition a knackered drive plate? I've only ever seen new ones fitted. R&D make new, don't recon.

#########################

 RCR - phutt.

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1 hour ago, j04n said:

Maybe, but would be surprised as reconditioned unit from RCR last year when I changed it from a D3. only done 100 hours. 

 

The drive plate is not part of the gearbox, and besides your D260 looks pretty beaten up so not much care appears to have been taken in its reconditioning. 

 

Up to you though. The symptoms you describe sound exactly like when my drive plate disintegrated. I too spent three months avoiding whipping the box off for a look before facing facts. The new drive plate was BLISS!!

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honestly, all advice is greatly received as I don't know hence asking on here. The engine has only done 350 hours, which again is no reason to discount it I know. Also when i nip up the stern gland, a little tighter than what i feel i should, the rattle all but stops for approximately 3 hours cruising, which leads me to think, maybe wrongly, that it is an alignment problem. 

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1 minute ago, j04n said:

honestly, all advice is greatly received as I don't know hence asking on here. The engine has only done 350 hours, which again is no reason to discount it I know. Also when i nip up the stern gland, a little tighter than what i feel i should, the rattle all but stops for approximately 3 hours cruising, which leads me to think, maybe wrongly, that it is an alignment problem. 

 

This is consistent with the drive plate falling to bits and supports my hypothesis. The engine does not rotate at a constant angular velocity and this is what causes the rattle at low revs. At higher revs there is more load to take up the backlash. Over-tightening the stern gland generates a higher load on the engine so to noise stops until the stern gland packing wears away a bit more. 

I agree 350 hours is low. Mine failed at 3,500 hours. Even so, the symptoms fit the diagnosis. 

 

Have you had a prop jam recently? These can easily bust a drive plate.

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it's more of a clonk than rattle and becomes more violent at high revs. However, it is more of a rattle in reverse......... if that makes any sense. no prop jams during the last 3 years I've had it. 

the frequency doesn't seem to increase with engine revs only the severity. 

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23 minutes ago, j04n said:

 

the frequency doesn't seem to increase with engine revs only the severity. 

That's odd. Its hard to trace things like that as the noise starts somewhere and is heard somewhere else. My thoughts are that if it is not grossly misaligned there is not much visible to cause noise, no failing joints except for that nylon bushed one and if there is no obvious loose bolts or damage then I can't imagine that it would rattle, What I would do is to disconnect the joint then run the engine, it will not be under any load so it could magically be smooth and silent but it might just show up a rattle, if its on rubber mounts give it a bit of a shove by hand or lever it around a bit with a bit of wood, I had an annoying tapping noise that I traced to an engine mount like that, whilst its disconnected try moving the coupling in every direction to see if there is metal to metal contact, after that I would have a look at the driveplate and after that I would go to the pub. Good luck.

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4 hours ago, j04n said:

it is a poor layout as actually there is masses of space only taken up with fresh water tank, waste water tank and engine all in line. When actually tanks could have been mounted either side. Although that would limit access to engine i guess. 

Tanks on the side cause the boat to list when full or empty as they weigh a lot and it changes daily, I know when I need a pumpout as a pencil rolls across the table and floor, and that tank is only 12 inches off centre and 250 litres, yours are probably bigger

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1 minute ago, Detling said:

Tanks on the side cause the boat to list when full or empty as they weigh a lot and it changes daily, I know when I need a pumpout as a pencil rolls across the table and floor, and that tank is only 12 inches off centre and 250 litres, yours are probably bigger

10-Carpenters-Pencil-Joiner-Pencil-Carpe

 

That's an easy fix ...

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I agree with everything Bizzard says - that's a really tight installation even by today's standards and you certainly don't have enough room for an Aquadrive.  If you choose to go down that route speak to either Nick or Steve at TW Marine http://www.twmarine.co.uk/index.htm- they know all there is to know about Aquadrives and will give you their time freely but don't bother with emails they simply don't have time to reply you have to keep trying to get them on the phone.

 

 

 

 

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1 hour ago, j04n said:

 

the frequency doesn't seem to increase with engine revs only the severity. 

 

Definitely not the drive plate then. 

 

With drive plate, the frequency rises with engine revs and disappears at some point as the revs rise.  

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