The International Cessna 170 Association

The pancake style right side exhaust on my 49 170A, is in poor shape while the left side is apparently newer and is still in good shape. Hate to replace something this expensive if I don't have to. Does anyone know of a reason why these two have to look alike? I say look because these old mufflers ain't, as they say, rocket science and I'd bet flow characteristics are pretty close. Thanks

Louie,
I'd really encourage you to become a member here. If you were one you'd have access to SK70A51-1 which answers your question. Your A&P should have access to this information as he will have to sign off the conversion.

Well what a coincidence. I just happened to read this post and thought, I wonder if Louie did join? And so I looked and surprise, he had just 9 minutes earlier, done so.

To answer your question Louie, it may or may not hurt anything having a mixed system, but it would raise questions among the knowledgeable.

There is a legal background to install 2 pancakes, replace them with Hanlon Wilsons and install the Hanlon Wilsons on later 170s. There is go such background for a mixed system and so you would be one your own to explain your actions.

Believe me, I feel your pain. We also have pancake mufflers and we are running out of spares.

Thanks for the input guys. I'll be in touch with AWI Monday.

Welcome to the Association Louie! You've probably now seen the "Remarks" paragraph at the bottom of the first page of SK70A51-1 which answers your initial question.

Thanks Gary!

After considerable searching I managed to locate a serviceable pancake type exhaust to replace the bad one (pictured) on my 170, almost. It's lacking the riser that inserts into the "Y" pipe. I've checked all the usual sources and can only find risers with the welded on flange. Does anyone know where I can get a 1.5" riser with flared (bell) flange. If I can find one of those I'll have it welded onto my old riser and should be good to go again.

Louie, I don't understand what the difference would be if you found a 1-1/2 pipe with the flange already welded on or found a pipe with a bell and had a flange welded to it.

I'd also be exploring maybe an unusual place for airplane parts but not for what your looking for and that would be a auto shop the makes their own pipe. A 1-1/2" piece of stainless pipe with a bell should be child play for them. Issues would be if their mandrels don't go that small and of course having the stock.

Not clear to me what you are welding. You're not welding the slip joint, are you?

Thanks Bruce, the problem I'm having is finding the riser with the bell or flange. There are lots of them out there with the flange welded to it. If I can find one I'll have it butt welded to my old riser.