flyingchump Posted April 19, 2021 Report Posted April 19, 2021 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? Quote
ragedracer1977 Posted April 19, 2021 Report Posted April 19, 2021 Those look fine to me. But I'm no expert. Mine looked bad.... 1 Quote
Tim Jodice Posted April 19, 2021 Report Posted April 19, 2021 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. 1 Quote
flyingchump Posted April 19, 2021 Author Report Posted April 19, 2021 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? Quote
Tim Jodice Posted April 19, 2021 Report Posted April 19, 2021 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. Quote
A64Pilot Posted April 19, 2021 Report Posted April 19, 2021 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 Quote
flyingchump Posted April 19, 2021 Author Report Posted April 19, 2021 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. Quote
Guest Posted April 19, 2021 Report Posted April 19, 2021 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? 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 Quote
Niko182 Posted April 19, 2021 Report Posted April 19, 2021 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. Quote
flyingchump Posted April 19, 2021 Author Report Posted April 19, 2021 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... Quote
Guest Posted April 19, 2021 Report Posted April 19, 2021 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 Quote
flyingchump Posted April 20, 2021 Author Report Posted April 20, 2021 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. Quote
carusoam Posted April 20, 2021 Report Posted April 20, 2021 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- Quote
Guest Posted April 20, 2021 Report Posted April 20, 2021 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. Most wouldn’t have issue using the AN363-720 in place of the AN365. Clarence Quote
flyingchump Posted April 25, 2021 Author Report Posted April 25, 2021 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? Quote
flyingchump Posted April 25, 2021 Author Report Posted April 25, 2021 (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? Edited April 25, 2021 by flyingchump Quote
Niko182 Posted April 25, 2021 Report Posted April 25, 2021 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. Quote
carusoam Posted April 25, 2021 Report Posted April 25, 2021 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- 1 Quote
Hank Posted April 26, 2021 Report Posted April 26, 2021 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. 1 Quote
Cody Stallings Posted April 26, 2021 Report Posted April 26, 2021 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. 1 Quote
flyingchump Posted May 1, 2021 Author Report Posted May 1, 2021 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 Quote
David Lloyd Posted May 1, 2021 Report Posted May 1, 2021 Should there be a spacer/washer between the engine and shock mount? Quote
flyingchump Posted May 1, 2021 Author Report Posted May 1, 2021 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? Quote
Hank Posted May 1, 2021 Report Posted May 1, 2021 3 hours ago, flyingchump said: 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? @M20Doc Quote
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