Ovation engine mounts

[Mark89114]

Haven't broken out the MM yet but wanted to get some input on excessive movement of the engine, which I can't tell when engine is running, maybe only slightly during start.  I have owned the plane 9 years and it had an OH engine installed at some point in time previous 4 years.  I will verify with logbook, my mechanic said 10 years is pretty good lifetime.....

This SCAT is getting crushed at some point in time, and looks like it is sitting up against the exhaust long enough to get it really hot.

I looked up the parts, at a high level and spruce has them for almost $700 apiece?  Is that right?  Seems steep.  

Assuming this is the problem, how involved to change them?  I will get to manual this evening.

Thanks,

Mark

[hypertech]

That may be a strategic squish and not a crush to get the tube away from the exhause.  That spot is tough as there is a lot of heat and not a lot of space.  After my engine overhaul, I burned through a couple tubes in that location.  Theoretically, there's an alternate exhaust config to move the hot spot to a different place.  The tube itself isn't that special and probably can be replaced with standard SCAT or SCEET.  Don't recall if I got my replacements there or at the factory but definitely didn't pay $700.  I ended up with a beefed up heat wrapping on the tube and heat shields on the exhaust spot there to finally stop the burn through of that tube.

[MooneyMitch]

37 minutes ago, hypertech said:

I ended up with a beefed up heat wrapping on the tube and heat shields on the exhaust spot there to finally stop the burn through of that tube.

Ditto.

[GeeBee]

The SCAT hoses are not heat resistant enough, that is why they are collapsing. The factory hoses are a fiberglass/nomex type hose with metal/fiberglass insulation wrapped around the alternate air duct. The fresh air ducts forward are P/N 64000-041 both left and right.  The alternate air duct (aft of the "Y" is 64000-039. The 64000-039 duct will have aluminum cloth wrapped around it. I used this stuff

https://www.amazon.com/Peastorm-Automotive-Aluminum-Material-Insulation/dp/B0BX4LHQFV?th=1

https://www.amazon.com/XINGO-Metal-Stainless-Multi-Purpose-Self-locking/dp/B0F37TQL9C/ref=sr_1_2_sspa?dib=eyJ2IjoiMSJ9.B_7FePlZ8pRPh65NsBK1fVcZaNcLygZexb5FMj7z7j26XV3QwyN7PGdTJIoC0KUn8bwnECr3cwhTN1MxzevBkZAGw7tW3xG8-COSzSLaNA0APeMVjippW1mP58463XzPSq18tYorqK9D85dF_Y45TFCRD9lEezMQ70Kjd6eSrkcIb9ErBs64mgQJTVE1UIpRzVGp4JHS04LY_nWVMo5Todr1rrB_sA4w2Cm-hDgim1Y.MZiIYri2Vs-KXwyOepfOMGbLJF_dbJgbiWt8CRzgFnc&dib_tag=se&hvadid=693717042847&hvdev=c&hvexpln=67&hvlocphy=1015313&hvnetw=g&hvocijid=10562764196515169393--&hvqmt=e&hvrand=10562764196515169393&hvtargid=kwd-48287672&hydadcr=24629_13611841&keywords=stainless%2Bsteel%2Btie%2Bwraps&mcid=2d9960f39cff3e5291112489ff7518ca&qid=1755109882&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

You can use Permatex black or red silicon in place of RTV-108

The IPC says the following:

WRAP 640001−39 DUCT WITH ONE LAYER ALUMINIZED CLOTH. LAMINATE TO DUCT WITH

THIN LAYER OF RTV−108 BETWEEN SURFACES. CLAMP WITH WRAP LOCK #2802 AT EACH

END AND AT CENTER OF WRAP.

 

 

 

 

[Yetti]

On 8/13/2025 at 1:36 PM, GeeBee said:

The SCAT hoses are not heat resistant enough, that is why they are collapsing. The factory hoses are a fiberglass/nomex type hose with metal/fiberglass insulation wrapped around the alternate air duct. 

You can use Permatex black or red silicon in place of RTV-108

The IPC says the following:

WRAP 640001−39 DUCT WITH ONE LAYER ALUMINIZED CLOTH. LAMINATE TO DUCT WITH

THIN LAYER OF RTV−108 BETWEEN SURFACES. CLAMP WITH WRAP LOCK #2802 AT EACH

END AND AT CENTER OF WRAP.

 

 

 

 

So would you not want to just find the proper duct material at a better price.   Not sure this is it, but looks to be correct.  this is 4"

https://hosewarehouse.com/products/flexaust-ns-4-inch-air-and-fume-duct-hose-12ft?srsltid=AfmBOor7dt7zyncFUCJXtj0TO_3EOpPv2xEh9zguC8K7Ii0lQqJ2-jjj

Comes in 12 foot lengths.    Group buy?   Only rated to 550 degrees.

https://www.ducting.com/product/silico-550-nomex/

 

[GeeBee]

3 hours ago, Yetti said:

So would you not want to just find the proper duct material at a better price.   Not sure this is it, but looks to be correct.  this is 4"

https://hosewarehouse.com/products/flexaust-ns-4-inch-air-and-fume-duct-hose-12ft?srsltid=AfmBOor7dt7zyncFUCJXtj0TO_3EOpPv2xEh9zguC8K7Ii0lQqJ2-jjj

Comes in 12 foot lengths.    Group buy?   Only rated to 550 degrees.

https://www.ducting.com/product/silico-550-nomex/

 

The factory stuff is uncoated. Not sure I would want the coating breaking loose since some of it is on the unfiltered side, although I doubt it would. 

[Mark89114]

All noted on the type of tube and crushing.  Will consider better ways to make work.  
 

I am more interested in the engine mounts and installing new rubber donuts in there.  Do’s, don’ts, what I need to do to make my life easier.  The engine was replaced in 2011 and there is a specific note that says mounts (I would assumes rubber pieces) were not replaced.  That puts age of rubber mounts at 14 years, have not gone farther back than that in logbooks. 

This last annual both exhaust hangers were broken, again they are 25 years old, that tube was worn, replaced it, came back from first long trip and it had worn through again.  Worse than before.  Which led to looking at mounts in more detail.  
 

 

[Yetti]

seems to me that a metal stand off heat shield on the exhaust pipe should also be fashioned for that area.   Trying to remember if there was not one on the F model

[hypertech]

23 hours ago, Mark89114 said:

All noted on the type of tube and crushing.  Will consider better ways to make work.  
 

I am more interested in the engine mounts and installing new rubber donuts in there.  Do’s, don’ts, what I need to do to make my life easier.  The engine was replaced in 2011 and there is a specific note that says mounts (I would assumes rubber pieces) were not replaced.  That puts age of rubber mounts at 14 years, have not gone farther back than that in logbooks. 

This last annual both exhaust hangers were broken, again they are 25 years old, that tube was worn, replaced it, came back from first long trip and it had worn through again.  Worse than before.  Which led to looking at mounts in more detail.  
 

 

Unless they are broken, wait until its time to overhaul again.  Everything is going to be in the way.  Its hard enough to put a set of new mounts on there with no accessories.  I would not touch this unless absolutely no other choices.

[Mark89114]

Me and an associate replaced them in about 4 hours this morning.  Wasn't terribly difficult, wasnt easy either.  The engine was moving too much, the crushed tube, broken exhaust hangers and i noticed a small wear mark on the spinner cooling interface.  They needed to be replaced, they were original to the airplane in 2000.  You can see from these pictures the wear/compression on them.