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68 M20F Alternate Air Valve


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Good day to all.  My 1968 M20F is in the shop right now and one of the discrepancies found during the annual is that the Alternate Air Valve for the engine intake is shot.  They are trying to source another valve but are of course having difficulty.  I figured this is the best place to ask if anyone knows of a source for this item.  I am not with the plane, so I am not sure if just the valve can be replaced or if this involves replacing the entire air filter induction box.   I have done my due diligence with Google and the websites for salvage yards to locate these parts without any luck.  Any insight or help would be greatly appreciated.

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40 minutes ago, MilitaryAV8R said:

Good day to all.  My 1968 M20F is in the shop right now and one of the discrepancies found during the annual is that the Alternate Air Valve for the engine intake is shot.  They are trying to source another valve but are of course having difficulty.  I figured this is the best place to ask if anyone knows of a source for this item.  I am not with the plane, so I am not sure if just the valve can be replaced or if this involves replacing the entire air filter induction box.   I have done my due diligence with Google and the websites for salvage yards to locate these parts without any luck.  Any insight or help would be greatly appreciated.

What is wrong with it? There isn’t much that can go wrong with it that can’t be fixed. 

Are you talking about the alternate air valve or the ram air valve? They can both easily be repaired with some rivets and baffle seal.

Edited by N201MKTurbo
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Are you talking about the power boost air seal or the large round disc that will open if the air filter is clogged?

If it is boost air seal I have used a piece of engine baffling drill the rivets holding it together and replace the rubber seal part.   It takes an hour or two but not very difficult.

 

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Speaking with the shop they said that it is the valve that opens automatically if the filter is clogged.  Here is specifically what was sent to me in email about it.

 

alternate air valve is completely worn out, missing bushings and improper hardware. gasket is missing. I am trying to find a serviceable valve assembly.

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1 hour ago, MilitaryAV8R said:

Speaking with the shop they said that it is the valve that opens automatically if the filter is clogged.  Here is specifically what was sent to me in email about it.

 

alternate air valve is completely worn out, missing bushings and improper hardware. gasket is missing. I am trying to find a serviceable valve assembly.

So, replace the gasket and missing bushings and put in the proper hardware. It sounds like your mechanic doesn't fix anything. He just changes parts.

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2 minutes ago, N201MKTurbo said:

So, replace the gasket and missing bushings and put in the proper hardware. It sounds like your mechanic doesn't fix anything. He just changes parts.

I am actually overseas right now and this is my first annual with the plane.  I have no real clue what all is involved in this valve other than trying to look at everything in the parts manual.  From what your telling me though this should be more of a "repair" rather than a "replace".  Good information to know.  I can shoot him an e-mail.

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The alternate air systems have also improved over the years...

If flying in IMC where ice can be involved... the best alt air system should be considered....

Ask Andrew @Hyett6420 what it is like to experience engine icing over the North Atlantic...

So replacing rubber seals seems to be easy enough, if that is all it is...

But if it is worn metal parts that need to be replaced... Go modern...

Best regards,

-a-

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