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What do you think of these motor mounts...


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I've been having some vibration and want to get rid of it.

I'm just about to schedule a dynamic prop balancing and thought... I'd better check my motor mounts.

Prebuy inspection mentioned nothing, 3 separate service guys doing work in the mount area mentioned nothing, annual inspection mentioned nothing...  First year of ownership has been a bi!&h.

Here is what I found.  Both lower mounts are punctured and dry rotting.  Both upper mounts don't look too bad but are not very soft.  If I'm reading the date properly, the sure date was 1997, week 43!  Geez.

Looks like I need to order some mounts.  Please let me know what you guys think.  Any advice on Barry vs Lord?  Any tips for making the swap easier, faster, better?  

 

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PXL_20210418_202502055.PORTRAIT.jpg

PXL_20210418_202746911.jpg

PXL_20210418_205546909.jpg

PXL_20210418_205617028.jpg

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I would replace them. I just replaced mine for a vibration issue. Like landing gear bungees they are square on the sides when new. I have no experience with Barry but so far so good with Lord.

20210317_133429.jpg

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11 hours ago, Tim Jodice said:

I would replace them. I just replaced mine for a vibration issue. Like landing gear bungees they are square on the sides when new. I have no experience with Barry but so far so good with Lord.

Did your vibration issue resolve?  

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32 minutes ago, flyingchump said:

Did your vibration issue resolve?  

Of course I leave out the most important thing! Yes it did. they were squashed so much that it required removing one set of washers on the bottom mounts. 

The bottoms were bad the the top were okay, I replaced all 4.

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They are bad, but there are different conditions of “bad”, as an opinion. Meaning that if you had no issues I wouldn’t ground the airplane and change them, but would order them and put them on the shelf for the next scheduled maintenance.

Mounts go bad in different ways, some soften up, and a lot of times that’s due to a oil leak, oil will eat rubber pretty quick. But often they sag and sometimes get hard as a rock and even split.

My experience with elastomerics is that they don’t cause vibrations, but may allow them to be felt.

‘In other words I’d replace them, and have the prop balanced, because I believe that constant flexing from vibrations will prematurely wear them 

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18 minutes ago, A64Pilot said:

They are bad, but there are different conditions of “bad”, as an opinion. Meaning that if you had no issues I wouldn’t ground the airplane and change them, but would order them and put them on the shelf for the next scheduled maintenance.

Mounts go bad in different ways, some soften up, and a lot of times that’s due to a oil leak, oil will eat rubber pretty quick. But often they sag and sometimes get hard as a rock and even split.

My experience with elastomerics is that they don’t cause vibrations, but may allow them to be felt.

‘In other words I’d replace them, and have the prop balanced, because I believe that constant flexing from vibrations will prematurely wear them 

Thank for your advice. 

Funny thing is that I have no sag.  I would have expected sag after the lower mounts had leaked out all the silicone, were exposed to an engine oil leak, and are 24 years old...  Like you said they go bad in different ways. 

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21 hours ago, flyingchump said:

I've been having some vibration and want to get rid of it.

I'm just about to schedule a dynamic prop balancing and thought... I'd better check my motor mounts.

Prebuy inspection mentioned nothing, 3 separate service guys doing work in the mount area mentioned nothing, annual inspection mentioned nothing...  First year of ownership has been a bi!&h.

Here is what I found.  Both lower mounts are punctured and dry rotting.  Both upper mounts don't look too bad but are not very soft.  If I'm reading the date properly, the sure date was 1997, week 43!  Geez.

Looks like I need to order some mounts.  Please let me know what you guys think.  Any advice on Barry vs Lord?  Any tips for making the swap easier, faster, better?  

 

mount1.jpg

PXL_20210418_202502055.PORTRAIT.jpg

PXL_20210418_202746911.jpg

PXL_20210418_205546909.jpg

PXL_20210418_205617028.jpg

The lowers don’t look good and the upper bolts are tool long.  There are too many washers installed, you could go one dash shorter.

Clarence

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My engine had some vibration issues going below 2450 rpm, so I switched out the mounts 2 days ago. Im picking up a hose that i ripped tomorrow and will update when flying on wenesday. The mounts where stock from 1999 so im hoping the difference is noticable.

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59 minutes ago, M20Doc said:

The lowers don’t look good and the upper bolts are tool long.  There are too many washers installed, you could go one dash shorter.

Clarence

I would assume as the mounts compress over time, more washers are added to make up the difference?  Could this be another sign that the mounts are bad? assuming they were the right bolts in the first place...

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2 minutes ago, flyingchump said:

I would assume as the mounts compress over time, more washers are added to make up the difference?  Could this be another sign that the mounts are bad? assuming they were the right bolts in the first place...

The internal spacer determines the total length.  If it’s missing the bolt will never reach full torque value.

Clarence

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1 hour ago, M20Doc said:

From the IPC.

Clarence

I was looking at this earlier today and what nut to use concerned me.  AN363-720 is called for the C and D.  The bottom line, AN363-720, doesn't specify the E and F model.  The AN 363's are currently installed.  I thought the AN365 were the fiber lock nuts and don't take heat very well. 

 

image.png.c70870462205127b9e93724872fc98fe.png

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The way rubber goes bad...

Under stress... compression and temperature...

They flow slowly... incredibly slowly...

When discussing rubber donut health... start with how old they are... how long they have been in place... how many hours of operation they have had...
 

If you are getting vibration... the kind that shakes the Mag compass...

Be on the look out for squashed motor mounts, and don’t forget the broken welds on the engine mount...

Pp thoughts only, not a mechanic...

Best regards,

-a-

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10 hours ago, flyingchump said:

I was looking at this earlier today and what nut to use concerned me.  AN363-720 is called for the C and D.  The bottom line, AN363-720, doesn't specify the E and F model.  The AN 363's are currently installed.  I thought the AN365 were the fiber lock nuts and don't take heat very well. 

 

image.png.c70870462205127b9e93724872fc98fe.png

Most wouldn’t have issue using the AN363-720 in place of the AN365.

Clarence

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On 4/19/2021 at 6:59 PM, Niko182 said:

My engine had some vibration issues going below 2450 rpm, so I switched out the mounts 2 days ago. Im picking up a hose that i ripped tomorrow and will update when flying on wenesday. The mounts where stock from 1999 so im hoping the difference is noticable.

Any Pirep? 

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Posted (edited)

Another question.  

I have the new motor mounts but cant get them installed for probably 2 weeks.  I can have the prop balanced within a few days...

The guy who will be balancing my prop said it makes no difference if I balance the prop first then change the mounts later or change the mounts first then balance the prop.  He said he balances the prop to the motor and the mounts have no real impact.  

Is there a better order of operations here?

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4 hours ago, flyingchump said:

Any Pirep? 

Definetely an improvement on vibration. A lot smoother at lower rpms, but the most noticable one was on takeoff and full power. Id also just get the prop balanced right now. Its cheap and easy.

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9 hours ago, flyingchump said:

Another question.  

I have the new motor mounts but cant get them installed for probably 2 weeks.  I can have the prop balanced within a few days...

The guy who will be balancing my prop said it makes no difference if I balance the prop first then change the mounts later or change the mounts first then balance the prop.  He said he balances the prop to the motor and the mounts have no real impact.  

Is there a better order of operations here?


Expect that balancing the prop... is a study of the rotating mass...

What you feel in the seat... will change with the rubber mounts...

The prop/engine are going to generate the vibration...

The engine mount is going to dampen them before they reach the airframe...

 

Where is your prop balancer mounting his sensor?

We can always invite @Cody Stallings if he is around...

Best regards,

-a-

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1 hour ago, carusoam said:


Expect that balancing the prop... is a study of the rotating mass...

What you feel in the seat... will change with the rubber mounts...

The prop/engine are going to generate the vibration...

The engine mount is going to dampen them before they reach the airframe...

 

Where is your prop balancer mounting his sensor?

We can always invite @Cody Stallings if he is around...

Best regards,

-a-

My prop balance sensors were mounted on the spinner.

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14 hours ago, flyingchump said:

Another question.  

I have the new motor mounts but cant get them installed for probably 2 weeks.  I can have the prop balanced within a few days...

The guy who will be balancing my prop said it makes no difference if I balance the prop first then change the mounts later or change the mounts first then balance the prop.  He said he balances the prop to the motor and the mounts have no real impact.  

Is there a better order of operations here?

Definitely wait till your isolators are installed before you balance your prop, you will be happy you did.

 

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So I need some help here.  I just changed out the old mounts for new Barry mounts.  The bottom mounts don't sit flush against the motor...  I referenced the service manual, the instructions that came with the mounts, and various posts on mooney space and others.  As far as I can tell I followed all instructions.  My ap and I are stumped.  Please help with advice!

Io-360a1a

1966 m20e

4x Barry mounts 94011-02

 

 

PXL_20210501_153103040.jpg

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13 minutes ago, David Lloyd said:

Should there be a spacer/washer between the engine and shock mount?

That's what I'm thinking...  Either it's the wrong mount or there is a spacer that I haven't seen in any of the documentation.  Maybe m20doc is around?

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