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Author Topic: Vibration  (Read 563 times)

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oldcatsailor

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Vibration
« on: October 27, 2019, 03:15:02 PM »

Marina checked drive train for vibration told me they found the transmission  may be the cause.lived with it now boat pulled for winter was pulling trans. To get to bottom bolt loosened motor mounts starboard  then found  broken  port engine bracket. Going to re bolt trany? Anyone know nounin
 source for motor mount. 1990 m35
« Last Edit: October 27, 2019, 05:07:19 PM by oldcatsailor »
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Roc

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Re: Vibration
« Reply #1 on: October 29, 2019, 09:10:09 AM »

looks to me your vibration is the broken motor mount and not the transmission.  You may want to try this site for motor mounts.  They used to carry OEM motor mounts.
https://www.marinepartssource.com/

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Ron Hill

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Re: Vibration
« Reply #2 on: October 29, 2019, 02:57:06 PM »

Old Cat : Don't know about the M35 engine mounts, but if the OEM mounts were like those on the M25XP I'd look elsewhere for a Much Better engine mounts!! 
The M25XP OEM mounts were almost like the old Atomic Four - attached straight to the bed!

A thought

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Roland Gendreau

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Re: Vibration
« Reply #3 on: October 29, 2019, 07:40:28 PM »

The picture is not that clear but from what I can see, what is broken is not the motor mount but the motor mount bracket.   On my m25xp, 2 of the brackets sheered off similarly ,  just inboard of the hole for the motor mount stud.   I found out that Westerbeke has a recall on those brackets. They provided me free 2 new brackets that have longer gusset plates to eliminate the problem.   
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Roland Gendreau
1992 MK 1.5
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Bristol, RI

lazybone

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Re: Vibration
« Reply #4 on: October 30, 2019, 10:50:17 AM »

I canít imagine how far out of alignment that engine would have to be to snap that 1/4Ē piece of steel.  The picture of the offset in the two parts after the stresses were relieved says it all.

Not the transmission.

PO are idiots.

That sort of asshatery can ruin bearings
« Last Edit: October 30, 2019, 11:25:51 AM by lazybone »
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Ron Hill

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Re: Vibration
« Reply #5 on: October 30, 2019, 02:16:38 PM »

Guys : The problem with the M35 engine mount brackets - that 1/4" was just bent metal and the bend was over stressed!!

A thought 
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Roland Gendreau

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Re: Vibration
« Reply #6 on: October 31, 2019, 02:08:14 PM »

The bracket failures are described in detail here:

 https://c34.org/bbs/index.php?topic=2935.0

They realized the failure was due to fatigue, so the new brackets have  gusset plates that are 1.5 inches longer.
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Roland Gendreau
1992 MK 1.5
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Bristol, RI

Jim Hardesty

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Re: Vibration
« Reply #7 on: November 01, 2019, 05:56:05 AM »

Quote
PO are idiots

In defense of Previous Owners, some commissioning dealers are cheep and lazy.  That much misalignment wasn't wear, it wasn't aligned at commissioning.  I bought Shamrock with about 400 engine hours, the cutlass bearing was a little worn.  Next season I replaced the cutlass bearing, aligned the engine and removed the "Align Engine" tag on the drive shaft.  Now have over 1500 engine hours and the cutlass bearing is still squeaky tight.

Jim


« Last Edit: November 01, 2019, 05:57:50 AM by Jim Hardesty »
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Jim Hardesty
2001 MKII hull #1570 M35BC  "Shamrock"
sailing Lake Erie
from Commodore Perry Yacht Club
Erie, PA

oldcatsailor

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Re: Vibration
« Reply #8 on: November 01, 2019, 10:38:22 AM »

Thanks all , called westabeake wait for them to get back to me.
Had part welded but would get new improved bracket .Had quite 207 $for a new part
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lazybone

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Re: Vibration
« Reply #9 on: November 01, 2019, 01:09:53 PM »

Guys : The problem with the M35 engine mount brackets - that 1/4" was just bent metal and the bend was over stressed!!

A thought

I trying to see the bent metal fabrication youíre referring too.  Please clarify.
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lazybone

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Re: Vibration
« Reply #10 on: November 01, 2019, 01:19:32 PM »

When aligning the engine all four mount top nuts should be backed way off so that there are no downward stresses.   The top nuts should not be tightened until the engine is aligned.
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S/V LAZYBONES  #677

jmcdonald

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Re: Vibration
« Reply #11 on: November 01, 2019, 01:24:22 PM »

I have had more the a little experience fabricating parts. Thatís a fabricated part, not a bent and formed
part.  If the original part failed, then a butt weld like that will fail, too. It needs a backing plate to have
enough strength to be cantilevered out like that after being repaired.  Look in the phone book, find a welding shop near you, they will happily make a new part for you a a very reasonable price. Thatís a very simple part to make.
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Ron Hill

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Re: Vibration
« Reply #12 on: November 01, 2019, 01:25:25 PM »

Ciao : I believe what they did was take a flat piece of metal cut into the shape of the engine mount and then bent it 90 degrees. 
That bend was stressed and that's what failed.  It worked for the M25 series engines, but the 4th cylinder made the engine that much heavier!!  The fix was a gusset welded to "support" that bend!!

A thought
« Last Edit: November 01, 2019, 01:30:28 PM by Ron Hill »
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lazybone

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Re: Vibration
« Reply #13 on: November 01, 2019, 01:35:35 PM »

Ciao : I believe what they did was take a flat piece of metal cut into the shape of the engine mount and then bent it 90 degrees. 
That bend was stressed and that's what failed.  It worked for the M25 series engines, but the 4th cylinder made the engine that much heavier!!  The fix was a gusset welded to "support" that bend!!

A thought

Did you look at the pics?  There is no break at a bend?  Itís a straight piece of steel with a break.
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Roland Gendreau

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Re: Vibration
« Reply #14 on: November 01, 2019, 07:34:54 PM »

As mentioned in my earlier post, the new brackets have a gusset piece (the triangular part welded to each leg) that is longer and extends all the way past the hole for the motor mount.   That will prevent the failure happening again due to fatigue. 

I agree the repair you did on the bracket will fail again at the weld. If you want to have the part fabricated locally, there may be a picture of the improved bracket somewhere on this site that the fabricator could use.  Hopefully Westerbeke will provide them to you gratis as they did for me.
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Roland Gendreau
1992 MK 1.5
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