Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 16-10-2011, 17:44   #16
Registered User
 
sailvayu's Avatar

Join Date: Mar 2006
Location: Fort Myers FL
Boat: Irwin 40
Posts: 878
Re: Big Vibration with New Engine ?

It is possible the mounts are too soft. Even new mounts of the wrong type can allow the engine to get into a harmonic oscillation really shaking the boat. I think more information is needed to figure it out but I would agree with the other posters and hold the money till the yard figures it out and makes it right. My experience dealing with Volvo is they are never wrong even as the engine is melting down and smoke and sparks are coming from it they refuse to admit it is anything wrong with THEIR motor! (I swear they said that on a new boat sea trial as the engine flew apart! They did give the guy a new motor in the end lol)
__________________

__________________
Capt. Wayne Canning, AMS
www.projectboat.info
http://sailvayu.com/
sailvayu is offline   Reply With Quote
Old 16-10-2011, 17:48   #17
Registered User
 
Reefmagnet's Avatar

Join Date: May 2008
Location: puɐןsuǝǝnb 'ʎɐʞɔɐɯ
Boat: Nantucket Island 33
Posts: 2,736
Re: Big Vibration with New Engine ?

Shot in the dark - resonance?

Edit: sailvayu beat me to it so what he said
__________________

__________________
Reefmagnet is offline   Reply With Quote
Old 16-10-2011, 17:48   #18
Registered User

Join Date: Apr 2011
Posts: 2,243
Re: Big Vibration with New Engine ?

Quote:
Originally Posted by cburger View Post
Misallignment issue, tranny to shaft coupling needs to be within .005 thousands of an inch and can be a very painstaking process that requires considerable time and patience to get right. Motor mounts should be changed out as GP as part of the repower. Run the motor at in gear at the slip and grab the shaft with your hand and you will feel distinct wobble if there is a problem with adjustment. I don't understand the term agent but who ever did the work should not be paid until the job is made right. The other issue is you don't want to run the motor like this to long as you can damage the tranny.
How would a misaligned tranny to prop shaft coupling result in vibration out of gear? It won't. Misaligned engine to gearbox might.

Won't grabbing the shaft with your hand while it's turning be both painful and possibly crippling?
__________________
MarkSF is offline   Reply With Quote
Old 16-10-2011, 17:54   #19
Sponsoring Vendor
 
Tellie's Avatar

Community Sponsor

Join Date: Oct 2007
Location: Hollywood, Fl.
Boat: FP Athena 38' Poerava
Posts: 3,046
Re: Big Vibration with New Engine ?

It's very likely the issue that is making it shake out of gear is still there when it is in gear just not noticable because the trans is firming the engine as it backs the torque against the trans. While it's impossible to diagnose over the Internet I'd suspect bad motor mount set up.
Tellie is offline   Reply With Quote
Old 16-10-2011, 19:02   #20
Registered User

Join Date: Apr 2011
Posts: 2,243
Re: Big Vibration with New Engine ?

Quote:
Originally Posted by Eleebana View Post
A friend of mine has just repowered his Beneteau 34.5 with a new 30 hp Volvo engine, done by the Volvo agent at Lake Macquarie. The engine is the same size as the previous Volvo and is of the model recommended by the agent. He has paid for the engine but not the labour for the fitting of it. The driveline has a massive vibration and is jumping all over the place when it is in neutral but when he selects forward or reverse it settles down and is quite normal. The agent has suggested he take it (& pay for it) because it should settle down after about 20 hours. He and I think not. It has had new mounts and the agent can't find the problem.

Does anyone have any ideas what might be the problem?

Greg
Unless the agent can suggest a convincing mechanism whereby a vibrating engine will get better after 20 hours, I would take it with a pinch of salt. Sounds like the kind of thing a less scrupulous car salesman would say.
__________________
MarkSF is offline   Reply With Quote
Old 16-10-2011, 19:19   #21
Senior Cruiser
 
S/V Antares's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: Annapolis, Bahamas
Boat: 1983 Gulfstar 36
Posts: 1,249
Images: 1
Re: Big Vibration with New Engine ?

Does the vibration clear as you ease up the throttle? If so you really need to use a photo tach or hand held mechanical one to set the correct Idle and while at it correct the panel tachometer.
__________________
Will & Muffin
Lucy the dog

"Yes, well.. perhaps some more wine" (Julia Child)
S/V Antares is offline   Reply With Quote
Old 16-10-2011, 20:08   #22
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
Re: Big Vibration with New Engine ?

Idle set too low
Misfiring Cylinder(s)
Wrong motor mounts
__________________
Chief Engineer is offline   Reply With Quote
Old 16-10-2011, 23:16   #23
Registered User
 
Sabbatical II's Avatar

Join Date: Apr 2009
Location: Lake Macquarie
Boat: Bluewater 420 CC
Posts: 756
Images: 1
Re: Big Vibration with New Engine ?

Well here's the answer.

The Volvo dealer upped the idle speed by 50 RPM this morning and the problem has gone. The owner did tell me that they set it at 850 RPM which was factory specification. However they've had to set it at 900 RPM so maybe the motor is a bit tight or whatever. I'm still amazed that the authorised Volvo dealer wants you to drive away when they know it's not right and all for a simple adjustment. I also let my friend know that if he joins CF he can have all this wisdom for free. Thanks everybody.

Greg
__________________
Sabbatical II is offline   Reply With Quote
Old 17-10-2011, 00:29   #24
Registered User
 
svBeBe's Avatar

Join Date: Sep 2008
Location: from Houston, TX; currently berthed in Barcelona, headed west
Boat: Amel SM 53 - BeBe
Posts: 946
Re: Big Vibration with New Engine ?

Quote:
Originally Posted by Eleebana View Post
The driveline has a massive vibration and is jumping all over the place when it is in neutral but when he selects forward or reverse it settles down and is quite normal.

Does anyone have any ideas what might be the problem?
Greg,

All diesel engines that I have seen vibrate at idle and then smooth out with a change in RPM, or a change in load. "Massive" is not really quantitative and there is no way for anyone to legitimately help you with your question, other than to advise your friend that if he feels something is wrong to seek a second opinion from an expert diesel mechanic.

Hope this helps,

Bill
__________________
svBeBe is offline   Reply With Quote
Old 17-10-2011, 04:49   #25
Registered User
 
pillum's Avatar

Join Date: Feb 2011
Location: In Aberdeen, Scotland, but retiring to Spain.
Boat: Westerly W-35 (Latterly sold as Conway 36 Aft Cockpit)
Posts: 509
Images: 28
Re: Big Vibration with New Engine ?

Quote:

Originally Posted by svBeBe
You guys are way too funny.

Do you think that CF is the only place to meet "experts?"

10 years ago there were other places, as there are other places today.

And, yes, 10 years ago, like I said in my original post, I was convinced the advice I got on a similar forum/group was genuine. It was not!

I hope that some of the virgins reading this thread will learn something from what I have said...but be careful virgins because I could be the person misinforming!

Bill
End quote

Sounds like it could be a costly problem, probably a good idea to pay an expert to look at it, rather than solicit input from a free forum.

Paul
__________________
Sweet are the uses of adversity.
pillum is offline   Reply With Quote
Old 17-10-2011, 06:15   #26
Registered User
 
cburger's Avatar

Join Date: May 2006
Location: Nyack, NY
Boat: Westsail 32
Posts: 1,547
Images: 1
Re: Big Vibration with New Engine ?

Quote:
Originally Posted by MarkSF View Post
How would a misaligned tranny to prop shaft coupling result in vibration out of gear? It won't. Misaligned engine to gearbox might.

Sorry, I missed the "Neutral" in the post.

Won't grabbing the shaft with your hand while it's turning be both painful and possibly crippling?
No, just did this last week as a final check to confirm allignment on a new installation after the boat was cruised under load, your hand will be very sensitive to potential problems. Maybe grab was the wrong word, more like grasp.
__________________
"All men are created equal, some are just more equal than others"
cburger is offline   Reply With Quote
Old 17-10-2011, 06:35   #27
Senior Cruiser
 
atoll's Avatar

Cruisers Forum Supporter

Join Date: Mar 2010
Location: gettin naughty on the beach in cornwall
Boat: 63 custom alloy sloop,macwester26,prout snowgoose 37 elite catamaran!
Posts: 9,311
Images: 75
Re: Big Vibration with New Engine ?

Quote:
Originally Posted by cburger View Post
No, just did this last week as a final check to confirm allignment on a new installation after the boat was cruised under load, your hand will be very sensitive to potential problems. Maybe grab was the wrong word, more like grasp.
don,t try this if wearing a neck tie..........
__________________
my catamaran building project updates http://www.cruisersforum.com/forums/...36#post2502136
atoll is offline   Reply With Quote
Old 17-10-2011, 09:26   #28
Registered User

Join Date: Apr 2010
Location: Newport News VA
Boat: Egg Harbor sedan cruiser 1970
Posts: 829
Re: Big Vibration with New Engine ?

Quote:
Misallignment issue, tranny to shaft coupling needs to be within .005 thousands of an inch
he says it is jumping around in neutral, so this coupling wont be spinning
__________________
sdowney717 is offline   Reply With Quote
Old 17-10-2011, 09:50   #29
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Re: Big Vibration with New Engine ?

Sounds like it could be a costly problem, probably a good idea to pay an expert to look at it, rather than solicit input from a free forum.

Paul
[/QUOTE]

My experience here is that there a lot of experts that help (for free) and that is as good or better than one paid "expert".
__________________
Who knows what is next.
Therapy is offline   Reply With Quote
Old 17-10-2011, 10:12   #30
Registered User
 
pillum's Avatar

Join Date: Feb 2011
Location: In Aberdeen, Scotland, but retiring to Spain.
Boat: Westerly W-35 (Latterly sold as Conway 36 Aft Cockpit)
Posts: 509
Images: 28
Re: Big Vibration with New Engine ?

Quote:
Originally Posted by Therapy View Post
Sounds like it could be a costly problem, probably a good idea to pay an expert to look at it, rather than solicit input from a free forum.

Paul
My experience here is that there a lot of experts that help (for free) and that is as good or better than one paid "expert".[/QUOTE]

I agree totally.
__________________

__________________
Sweet are the uses of adversity.
pillum is offline   Reply With Quote
Reply

Tags
engine

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
The Right Way to Run a Diesel off-the-grid Engines and Propulsion Systems 80 09-12-2012 19:06
How to Lift an Engine Charlie Engines and Propulsion Systems 38 03-09-2011 02:12
Cruisers Stranded - in Need of Advice Bright Eyes Engines and Propulsion Systems 61 02-08-2011 11:47
Stalling Universal 5424 Engine ryderstk Engines and Propulsion Systems 13 27-07-2011 10:20
Engine Vibrating Violently when Shifting to Neutral Heikki Engines and Propulsion Systems 24 13-07-2011 08:07



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:38.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.