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  #1  
Old 03-19-2018, 01:24 PM
helidriver helidriver is offline
 
Join Date: Aug 2016
Location: Aynor SC
Posts: 7
Default -6a engine mount wear

It's condition inspection time again and it looks to be not so good this year. Over the last year I have flown just over 200 hours and in that time I have managed to install a rub mark on my engine mount. I found that the left exhaust pipe has been rubbing the engine mount where it exits the engine cowl and doing quite a bit of damage. The rub mark mics out at 0.029" deep. I am sure this is a grounding measurement, or at least it's grounded until someone can give me guidance on what is acceptable. I am running a Lycoming O-320-D2J 160hp engine with the vetterman exhaust. Does any one know what the wear tolerance is or where to find it ? Can this be repaired and by who ? or does it mean I'm buying a new engine mount ? Thanks in advance
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  #2  
Old 03-19-2018, 02:04 PM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 395
Default

You should call Vans for guidance.

I found this type damage on one mount while performing an annual, not quite as deep as yours & had a welder fish patch a 4130 piece over the damaged area with TIG. Exceptional welder, he was able to do it on the plane. After re-painting the area, I attached a bit of baffle material to prevent future damage from the exhaust. Each annual the baffle material is removed to confirm no further damage is occuring.
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Last edited by Ralph Inkster : 03-19-2018 at 02:07 PM. Reason: grammar
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  #3  
Old 03-20-2018, 05:39 AM
helidriver helidriver is offline
 
Join Date: Aug 2016
Location: Aynor SC
Posts: 7
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Thanks Ralph,
I talked to the tech rep and sent pictures. He seemed to think it was able to be patched but would check with the engineers and let me know. I guess I’ll start pulling engine since it will have to come off either way. Unfortunately the option of being repaired in place won’t work for me. Thanks again
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  #4  
Old 03-20-2018, 09:24 AM
az_gila's Avatar
az_gila az_gila is offline
 
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 9,606
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The tubing is 3/4 x 0.049" 4130, so a 0.029" deep "notch" is a major structural defect.

Let us know how it gets fixed.

The AMT handbook even has a paragraph on engine mount repairs - end of this text - http://content.aviation-safety-burea...hapter5.php#13.

Key bit here -

The preferred method to repair an engine mount member is by using a larger diameter replacement tube telescoped over the stub of the original member using fish-mouth and rosette welds. 30° scarf welds are also acceptable in place of the fish-mouth welds.
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Last edited by az_gila : 03-20-2018 at 09:32 AM.
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