[f-AA] What exhaust gaskets work best?

[Sam Burke]

I have some exhaust pipe flanges that are a little worn and I am asking the group what type of exhaust gasket works best for rough flanges?  I has some of the $8 spiral wound gaskets (PN 627429) and they do not seal well. I have a set of the metal gaskets which are cupped and are installed in pairs (PN 632837, 21493) but I hear that they may not be the best.  I understand that the old copper and asbestus gaskets will make a good seal to a rough flange surface but I do not have the part number. Any thoughts?

Regards,

Sam Burke N6404C  1947 Aeronca L16A  C85-12  7BCM-296  USAF 47-1076

[Dan Vandermeer]

You might try to double up on the metal gaskets. Use two new gaskets rather than just one. This worked well on a O-200 I know of. 

Dan v

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[Cy Galley]

Check the flanges flatness. Hammer the ears down so they are out of the way. Assemble with a like Muffler cement. The most gaskets are a onetime use so use new each time.

 

 

Cy Galley; Aeronca Aviator

Supporting Aeroncas every day

www.aeronca.org   

518-731-3131

[Scott Johnson]

I have found some of the copper asbestos ones on ebay. seems like I
found it on an O-300 search.

Scott

[Sam Burke]

Scott, 

Thanks for the ebay suggestion, I ordered 4 of the listed gaskets since they look like what I am looking for. They list the Continental PN as 5210-A and the notes list my C85 engine.  I find in my 1949 Continental C85 engine parts manual a part number 25376 which hopefully is the same part. I am thinking of using some muffler cement on any rough areas of the exhaust stack flange as Cy suggested, thanks Cy. 

Regards,

Sam Burke N6404C  1947 L16A  C85-12  7BCM-296  USAF 47-1076

[Ian Harvie]

Doubling up back to back is recommended. Aren't the thin SS ones called
"No Blow" I find the thick expensive ones can leave the stud too short
if its been screwed into the head too far.

Ian

On 23/03/2013 10:46 PM, Dan Vandermeer wrote:
> You might try to double up on the metal gaskets. Use two new gaskets
> rather than just one. This worked well on a O-200 I know of.
> Dan v
>
> Sent from my iPhone
>
> On Mar 23, 2013, at 12:53 AM, Sam Burke <samb...@verizon.net

> <mailto:samb...@verizon.net>> wrote:
>
>> I have some exhaust pipe flanges that are a little worn and I am
>> asking the group what type of exhaust gasket works best for rough
>> flanges? I has some of the $8 spiral wound gaskets (PN 627429) and
>> they do not seal well. I have a set of the metal gaskets which are
>> cupped and are installed in pairs (PN 632837, 21493) but I hear that
>> they may not be the best. I understand that the old copper and
>> asbestus gaskets will make a good seal to a rough flange surface but
>> I do not have the part number. Any thoughts?
>>
>> Regards,
>> Sam Burke N6404C 1947 Aeronca L16A C85-12 7BCM-296 USAF 47-1076
>>
>>
>>
>>
>> _______________________________________________
>> Aeronca mailing list

>> Aer...@westmont.edu <mailto:Aer...@westmont.edu>
>> http://mail.westmont.edu/mailman/listinfo/aeronca

>
>
> _______________________________________________
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> Aer...@westmont.edu
> http://mail.westmont.edu/mailman/listinfo/aeronca
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[Dan Vandermeer]

Exactly so.

Dan v

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[Tom Holmes]

The thin ones that are "dimpled" work really well, and can be doubled successfully.

Tom, the taxier, from Tampa

>> Checked by AVG - www.avg.com <http://www.avg.com/>

[Roger Anderson]

One of my exhaust pipe flanges is worn also. I've used the double back to back SS "no blow" gaskets and so far so good.

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[Scott Johnson]

Might be worth getting an extra set or two as these are not made
anymore. I think someone just found a bunch of old stock.

Scott

[CaptG...@aol.com]

The old copper asbestos is you can find any. Otherwise is use the Rapco gasket. You can find their picture,etc.,  at Aircraftspruce.com.

 

[Scott Johnson]

FWIW, the spruce book shows the gaskets nested together with the U
side facing the cylinder. Another school says nested with the U
facing the pipe. I talked with a rep from Continental some years ago
and he stated the they are not supposed to be nested and that one U
should face the cylinder and one should face the exhaust.

Scott

[joer...@suddenlink.net]

Since the $8 spiral wound gaskets won't hold, (you did grind them for clearance against the other cylinder's intake elbow where necessary?), I would expect machining the exhaust ports flat and true and machining the exhaust flanges to flat and true will be necessary. If the exhaust flanges are beyond a flattening, they'll need replaced. I'm figurin' that by the time you got to asking here, the problem is beyond an easy fix. jrh

[Sam Burke]

Roger, 

The instructions that I have from Aircraft Spruce say; " Raised bead facing the exhaust stack flange -- These may be used in pairs with raised beads interlocked, if desired". 

Regards,

Sam Burke N6404C  1947 L16A  C85-12  7BCM-296  USAF 47-1076

[Sam Burke]

Thanks Scott, that information is appreciated.  The attached illustration then is not correct then?

[Sam Burke]

Joe, 

Thanks for the suggestion, yes I did grind down the flange faces and hammer the side of the flanges a bit so the center bears against the head opening. I ordered some of the old copper and asbestus gaskets on eBay, I understand that they conform to irregularities better than the flat gaskets. 

[Scott Johnson]

According to that rep it would be incorrect. The top one would need
to be flipped 180 degrees. When I told him about the Spruce catalogue
illustration he said "that must be where it is coming from . I will
try to get a follow up to see if that is still what they are saying.

Scott

[Roger Anderson]

I'm pretty sure, been a couple of years, mine are back to back with a raised curve up and a raised curve down. They end up being mashed flat anyhow. So maybe it doesn't really matter.  Don't know.  

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