The International Cessna 170 Association

Yesterday my A&P discovered a crack on the exhaust system flange that attaches to cylinder #1. He's spent the past day calling all the majors (Wag, Knisley Exhaust, Aerospace Welding Minneapolis, Dawley, etc.) and he has been told by each one he has called that they are not accepting the pancake-style exhaust systems in for repair any more. I've spent quite a bit of time trolling posts on the board looking for a hidden gem that might put us in contact with someone who could do the repair to no avail. In a perfect world we would like to send out both left and right for eval and repair, just to make sure there aren't any other unseen defects anywhere, but seems that we can't find anyone to help.

One option is to replace with the Hanlon-Wilson system, but we would need to rip out everything and replace both left and right. Advantage: spanking-new exhaust, safe flying, trouble-free service for years to come. Disadvantage: horribly expensive.

I'm grasping for suggestions on where we could search for either a replacement or a spot that might be able to repair it for us, and would appreciate anything you could share.

(Photos are from my A&P)

Thanks -

Brian,
First, I’m no expert on the pancake style muffler. So take the following advice with that in mind.

The C-170A IPC shows the “muffler assembly” in fig. 38-39 but it doesn’t depict any risers. I don’t see the risers illustrated anywhere else though. If p/n 0550290-1 includes the risers and flanges it appears that KRN has a new one in stock. Unlike aircraft instruments — if you are stuck with repairing your system — there is no requirement that it has to be repaired by an aircraft exhaust repair shop. As long as your A&P will sign off on the repair you can have anybody weld it. I would certainly go to a certified welder though. Paragraph 8-50 of AC 43.13-1B talks briefly about repairing aircraft exhaust. Aircraft Exhaust, Inc. may be able to help with parts to repair it with.

Try Acorn Welding in Canada, 888-388-8803 or 780-447-5955. They do all sorts of odd exhaust systems repair.

Not that hard to fabricate a new flange, weld a new tube stub to it, cut the old riser near the existing weld, and weld the new one on. Of course alignment is important, but it would be a pretty simple fixture to capture alignment.

Eventually you will probably have to give up on the pancake muffler system (as I had to), but if that is the only issue with your system, a repair seems pretty practical to me.

One other advantage of changing to the Hanlon-Wilson type of exhaust: My heater system worked MUCH better after changing to it.

I know first hand Acorn stands behind their work. They can be pricey but it also could be me remembering the good old cheap days

Acorn welding are very good exhausts . We have purchased systems from them years ago And still find their product serviceable And first rate . They might be a little higher in price but it’s worth it in the long run. Plus good people to do business with . Yep, just a shameless plug and do not forget my discount .

All - thank you very much for the suggestions. It looks like we may have found a "loaner" to get 62C back in the air while we sort this out. I'll check with the A&P to see if he has tried Acorn yet, and hopefully they are agreeable to helping us with the weld. At least the buffer of time will take some of the decision-urgency away.

WallColmonoy used to do them (Pancakes) but they inform me they are now only taking “Piecemeal” repair orders and the customer would have to send a picture for evaluation as they will undertake them on a “hardship” basis... for a quote...and expect 45 days.

However, they did provide a lead for another company they suggest that does such work (I did not call them but here’s the lead): http://www.dawleyaviation.com/?_vsrefdo ... 89EALw_wcB

Thanks, George. My A&P had already reached out to Dawley and they were not willing to perform repairs on the old pancake units.

OK, well... when you finally decide to convert to the much-better Hanlon Wilson system.... AWI (Aerospace Welding Inc in Minnesota) is the folks that support us, give great service, have the complete conversion system and Charlie Felds is the person to ask for (Tell him you’re a Member and where you got the recommendation to call him.

You want two LEFT MUFFLERS when you convert to a HW system from pancakes, and Charlie knows the kit and requirements.

Question about converting from pancakes to Hanlon-Wilson. I'm biting the bullet and doing the conversion while installing an overhauled engine. I'm clear on most of it (two left-hand mufflers and shrouds) but for the tailpipes, do I need two lefts or one each right and left? And AWI lists two types of tailpipe clamps, "with pin" and "no pin". What do I want?

Left/Right and I recommend WITH pin. (YOu’ll drill the tailpipe to match)