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Looking for LH Exhaust C85-12

Tgarcia

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Hi Guys,

I'm currently looking for a Left side exhaust stack for a C85-12. Does anyone have one they might want to part with?

Tadd
 

JimC

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Have you considered modifying a 65 stack?
 

Tgarcia

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Hi Jim,

It seems like that would be the easiest thing to do. I have searched around this site but have found no information about how to modify the exhaust, only that it can be done. Can you give me a little more info or direct me somewhere to find out how to do this? Could a regular muffler shop modify the stack or should it be sent to someplace in particular?

Thanks

Tadd
 

JimC

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you would get a more professional job (and legal) if you send it to a shop that specializes in aircraft exhaust repairs. Since one of your stacks has already been modified, you should send both to assure that they match. You can search this website for more information about exhaust modification.
 

Tgarcia

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I talked with Larry at Dawley aviation today regarding getting a new LH stack. He said that they can make me one for $324.

He also told me that they can modify both stacks and slightly angle them down so to clear the oil screen on the C85-12. I was wondering if anyone has ever heard of this? He said that they do it all the time. I'm concerned that tilting the stacks down will get in the way of the cowling. Anyone?
 

huston marlowe

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The usual advice with a -12 is to lower the muffler to clear and then extent the stacks down to match the lower muffler. This means the hole in the cowl must be lower too. I'd look for an exhaust routing that would preserve the stock cowl if it were me. You are making a custom exhaust system so try to do it all in the exh system design.
 

N42532

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As has been said but perhaps not clear is this. You must lower the muffler of the -12 in order to get to the oil screen. This lower muffler position will necessitate modifying the cowl opening for it.

How the exhaust headers are modified to meet the new muffler position probably doesn't matter. Most that I've noticed had both the front and back vertical down pipe extended the same allowing the horizontal pipe to run more or less parallel when in flight. Dawley seems to be suggesting increasing the length of just the rear vertical down pipe thus the horizontal pipe would not ever be more or less parallel.

This is probably more of a look thing than any operational difference. Either way you still have custom exhaust one just being a bit more costume from my view.
 

JimC

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I would do it the way everyone else does it, extending all 4 of the downpipes equally.
 

huston marlowe

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Could one minimize the muffler reposition if the exhaust system was disconnected from the heads for pulling the screen ? (I must go look at a -12 to understand the problem). I'd personally be willing to pull the stacks and muffler every 25 hrs or at annual in order to preserve the stock cowl parts. My Cub had a -12 engine as its second engine and now has a -8 for the third. The logs and appearance of the cowl skins seem to indicate they are original so my guess is that the -12 engine (with block off plates) had an exhaust system that did not allow the screen to be pulled very often. Not butchering the yellow parts would be a priority for me !
 

JimC

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You can minimize it somewhat if you crush the muffler shrould in till it
touches the muffler.
 
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