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Vetus Flexi coupling

Paul Osterberg
 

Hello!
I found several lose nuts on my Vetus flexi couplig,
How hard shall they be torqued? I do not need Nm, but like Firm, Hard or super hard?. is it OK to put the engine in gear to have something firm to torque against else difficult to prevent the coupling from rotating 
Paul on SY Kerpa SM#259

Danny and Yvonne SIMMS
 

Hi Paul. Answer to your forst question. Appropriate tightness for the bolt size. that is "as much as it will take" If they are loose you should check the condition of the rubber bushes unless you have done so recently. This will require moving the motor back. Fortunately an easy, fish hook free, operation thanks to the Amel girders that the motor sits on. I have seen some owners make a big deal out of this. It is not.

Regards

Danny

SM 299

Ocean Pearl

On 28 May 2019 at 05:23 Paul Osterberg <osterberg.paul.l@...> wrote:

Hello!
I found several lose nuts on my Vetus flexi couplig,
How hard shall they be torqued? I do not need Nm, but like Firm, Hard or super hard?. is it OK to put the engine in gear to have something firm to torque against else difficult to prevent the coupling from rotating 
Paul on SY Kerpa SM#259

Craig & Katherine Briggs SN 68 Sangaris Tropic Isle Harbor, FL
 

Paul, I'd add to Danny's advice and suggest you also use Nyloc nuts and/or red Locktite.
Craig

Paul Osterberg
 

Danny, Craig
Do have nylock nuts, did change the whole units 2016 in Turkey, so hope it should be OK for now. Will have a lock at it when back in my home-port later coming fall.
Paul on SY Kerpa SM#259 Bermuda

Craig & Katherine Briggs SN 68 Sangaris Tropic Isle Harbor, FL
 

Paul, 
Surprising the nylocs loosened - maybe nylocs AND locktite with a little bubble gum ;-)
Btw, for leverage when tightening, I use a long screwdriver under the coupling and over one of the bolts on the opposite side of the one I'm tightening. Have also used a chain wrench. Left the transmission in gear just to stabilize it a bit, but took most of the force with the screwdriver.
Don't recall the exact bolt size, but you can google the torque - M8 Class 10.9 for example is 40 Nm. 
Cheers, Craig, SN68 Sangaris, Tropic Isle Harbor 

Danny and Yvonne SIMMS
 

Hi Paul,

I agree with Craig, nylocs coming loose is unusual. I would check the rubber bushes. You may have metal on metal going on in there.

Regards

Danny

SM 299

Ocean Pearl

On 29 May 2019 at 22:47 "Craig Briggs via Groups.Io" <sangaris@...> wrote:

Paul, 
Surprising the nylocs loosened - maybe nylocs AND locktite with a little bubble gum ;-)
Btw, for leverage when tightening, I use a long screwdriver under the coupling and over one of the bolts on the opposite side of the one I'm tightening. Have also used a chain wrench. Left the transmission in gear just to stabilize it a bit, but took most of the force with the screwdriver.
Don't recall the exact bolt size, but you can google the torque - M8 Class 10.9 for example is 40 Nm. 
Cheers, Craig, SN68 Sangaris, Tropic Isle Harbor 

 

Or, more likely, an allignment issue. 

Best,

CW Bill Rouse
Yacht School - Supporting Amel Owners
www.YachtSchool.us
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970

On Wed, May 29, 2019, 2:36 PM Danny and Yvonne SIMMS <simms@...> wrote:

Hi Paul,

I agree with Craig, nylocs coming loose is unusual. I would check the rubber bushes. You may have metal on metal going on in there.

Regards

Danny

SM 299

Ocean Pearl

On 29 May 2019 at 22:47 "Craig Briggs via Groups.Io" <sangaris=aol.com@groups.io> wrote:

Paul, 
Surprising the nylocs loosened - maybe nylocs AND locktite with a little bubble gum ;-)
Btw, for leverage when tightening, I use a long screwdriver under the coupling and over one of the bolts on the opposite side of the one I'm tightening. Have also used a chain wrench. Left the transmission in gear just to stabilize it a bit, but took most of the force with the screwdriver.
Don't recall the exact bolt size, but you can google the torque - M8 Class 10.9 for example is 40 Nm. 
Cheers, Craig, SN68 Sangaris, Tropic Isle Harbor 

Paul Osterberg
 

Might be, no vibration though, I guess the nylock have been on and off a few times and the locking capability get reduced. time to replace the nuts maybe
Paul

karkauai
 

I understand that unlocks should be replaced every time you remove them...at least on critical applications.

Kent Robertson
S/V Kristy
SM243
USA cell: 828-234-6819

On May 29, 2019, at 4:48 PM, Paul Osterberg <osterberg.paul.l@...> wrote:

Might be, no vibration though, I guess the nylock have been on and off a few times and the locking capability get reduced. time to replace the nuts maybe
Paul

karkauai
 

Darn spellcheck...I guess unlocks is a bad name for nylocks.

Kent Robertson
S/V Kristy
USA cell: 828-234-6819

On May 30, 2019, at 6:25 AM, karkauai via Groups.Io <karkauai@...> wrote:

I understand that unlocks should be replaced every time you remove them...at least on critical applications.

Kent Robertson
S/V Kristy
SM243
USA cell: 828-234-6819

On May 29, 2019, at 4:48 PM, Paul Osterberg <osterberg.paul.l@...> wrote:

Might be, no vibration though, I guess the nylock have been on and off a few times and the locking capability get reduced. time to replace the nuts maybe
Paul

Craig & Katherine Briggs SN 68 Sangaris Tropic Isle Harbor, FL
 

"Unlocks" may be the right name for Paul's nylocks, though!

Gary Silver
 

Hi Kent:

You are correct that Nylock nuts a single use items (at least in aircraft applications and I assume in other critical applications).  They are also low heat suitable as nylon deforms at temperature.  I don't know how hot this area gets but perhaps metal locking nuts would be better.  In the aircraft industry metal locking nuts are used in virtually all engine compartment applications.  There are specially coated metal locking nuts that are suitable even on exhaust components. 
Various types such as  https://jlanfranco.com/products/all-metal-locknuts/    or  for aircraft https://catalog.continental-aero.com/viewitems/all-metal-lock-nuts/all-categories-all-metal-lock-nuts-aero-flex

You will have to do some research to find the metric size and grade you need. 

All the best, 

Gary S. Silver
s/v Liahona
Amel SM 2000 # 335
Puerto Del Rey Marina, Puerto Rico 

 

Gary,

I think you identified two big issues. The heat will reach the operating temperature of the engine, which is 80C. 

I just did a search of nylocs. The temperature range is all over the place, but 80 degrees seems within the range of all I checked that specify a temperature range. And 10-15 used seems to be the range of those that claimed multiple use. 

The fact is that most of us would not think of these things and grab nylocs from a bin without any verification of material used, or specifications. That fact, along with the fact that Chinese manufacturers probably make most of these, spells problems.

Best,

CW Bill Rouse
Yacht School - Supporting Amel Owners
www.YachtSchool.us
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970


On Thu, May 30, 2019, 9:17 AM Gary Silver via Groups.Io <garysilver=mac.com@groups.io> wrote:
Hi Kent:

You are correct that Nylock nuts a single use items (at least in aircraft applications and I assume in other critical applications).  They are also low heat suitable as nylon deforms at temperature.  I don't know how hot this area gets but perhaps metal locking nuts would be better.  In the aircraft industry metal locking nuts are used in virtually all engine compartment applications.  There are specially coated metal locking nuts that are suitable even on exhaust components. 
Various types such as  https://jlanfranco.com/products/all-metal-locknuts/    or  for aircraft https://catalog.continental-aero.com/viewitems/all-metal-lock-nuts/all-categories-all-metal-lock-nuts-aero-flex

You will have to do some research to find the metric size and grade you need. 

All the best, 

Gary S. Silver
s/v Liahona
Amel SM 2000 # 335
Puerto Del Rey Marina, Puerto Rico