Pancake Mufflers

Mike Smith · Post by **Mike Smith** » Mon Apr 03, 2006 5:00 pm

I've been looking around for a replacement pancake muffler and it seems that no one makes new ones anymore. Does anyone still make them? I called AWI and they only do the round ones. Aircraft Sruce only lists the round ones in their cataloge. I'd like to replace the right side muffler, will I be forced to buy the round ones if I can't fix my pancake muffler?

Post by **Bruce Fenstermacher** » Mon Apr 03, 2006 7:18 pm

Yes you will unless you can find someone to sell/give you their old system that may be repairable. I would think most are pretty shot buy now.

Bobo · Post by **Bobo** » Tue Apr 04, 2006 1:25 pm

Mike,

I am sure you are aware that WAG Aero will repair Pancakes. I had mine done there and they came out looking like new.
I just looked at their catalog and I think the price is about $370 per side.

Mike Smith · Post by **Mike Smith** » Tue Apr 04, 2006 11:47 pm

Thanks Bob, I'll look into that. How bad was your muffler when you sent it in?

Bobo · Post by **Bobo** » Wed Apr 05, 2006 2:09 pm

Mike,

They were useable but had a lot of cracks. When they came back
they were polished and all of the welds were redone.

Mike Smith · Post by **Mike Smith** » Wed Apr 05, 2006 3:02 pm

That sounds promising, I'll call them today. Thanks

Mike Smith · Post by **Mike Smith** » Wed Apr 05, 2006 4:31 pm

Every reputable aircraft exhaust welding person I've talked to over the last few days has declined to even try to repair such an old piece of equipment. I now suspect that the sales person at WAG Aero is wrong - or, I will spend $400 on a repair that will only last 1 or 2 years. I now believe I will need to buy the H-W replacement parts.

My question is: Where can I get a copy of the Type Certificate which says that my Make, Model and serial number is approved for this modification? The A&P/AI I'm working with says our local FSDO will not approve any Field modification so we need an approved product or an STC.

Will someone point me in the direction to acquire this documentation? I want to have it in hand so I don't spend money on a system the FAA will not sign-off.

Thanks

cessna170bdriver · Post by **cessna170bdriver** » Wed Apr 05, 2006 5:02 pm

Type Certificate A-799 is available in the members-only section of the Association website. Item 110 under Specifications Pertinent to All Models reads:

Hanlon-Wilson exhaust manifolds and carburetor air heater (Cessna dwg. 0550157)

The right side (cabin heater) may not be applicable to earlier airplane.

For all the parts relevant to 0550157, see the 170B IPC, page 89. There is a link posted elsewhere to download the IPC.

Hope this helps, Miles

Mike Smith · Post by **Mike Smith** » Wed Apr 05, 2006 5:15 pm

Thanks Miles, I did download and print the Type Certificate Data Sheet. In looking at it I was curious if the part you mentioned was the verbage I needed to make the A&P and FAA happy with the parts installed inplace of the pancake muffler.

I called Aerospace Welding and they have a complete system for the H-W modification on the C-170. It's $1998 but since I'm a TIC170A member they will give me a 5% discount (Thanks George, for your work getting that discount in place

). Charlie (at AWI) said it's a complete system which includes everything (nuts, brackets, gaskets, shroud, etc.) and that in 90% of the installations there is no problem with everything fitting as advertised.

I'm just looking to avoid any roadblocks by the FAA or the A&P/AI after I order the parts.

blueldr · Post by **blueldr** » Wed Apr 05, 2006 6:04 pm

If you switch to the HW exhaust system, don't forget the cross brace between the two mufflers. It may not be part of the package.

Mike Smith · Post by **Mike Smith** » Wed Apr 05, 2006 6:18 pm

I'll be sure and check on that. Thanks.

cessna170bdriver · Post by **cessna170bdriver** » Wed Apr 05, 2006 6:31 pm

Mike Smith wrote:Thanks Miles, I did download and print the Type Certificate Data Sheet. In looking at it I was curious if the part you mentioned was the verbage I needed to make the A&P and FAA happy with the parts installed inplace of the pancake muffler.

The TCDS is about as official as it gets. If they want a copy directly from the FAA, it's at http://www.airweb.faa.gov/Regulatory_an ... /A-799.pdf

Just remember there are two comletely different right sides depending on your cabin heat setup. Make sure you order the correct one for your particular airplane.

Mike Smith wrote:I'm just looking to avoid any roadblocks by the FAA or the A&P/AI after I order the parts.

If there's any doubt at all, get a detailed parts list from AWI, compare that to the IPC for your airplane, and get your FSDO and AI to approve the installation of that list of parts, all before you buy the parts.

Miles

cessna170bdriver · Post by **cessna170bdriver** » Wed Apr 05, 2006 6:39 pm

blueldr wrote:If you switch to the HW exhaust system, don't forget the cross brace between the two mufflers. It may not be part of the package.

Good catch, Dick. Oddly enough, this part is not shown on the exhaust system page. It's on the engine installation page, (p87, item -13 in the B-model IPC).

For SN 20267 through 25763: Part # 0550159
For SN 25764 and up: Part # 0550159-5

For older airplanes it's probably the first one, but check your IPC to be sure.

Miles

Mike Smith · Post by **Mike Smith** » Wed Apr 05, 2006 7:02 pm

My serial number is in the 19xxx series - it's a 1950 "A" model. AWI is sending me a parts list so I'll check that and see what I need to do from there.

Thanks,

Post by **GAHorn** » Thu Apr 06, 2006 5:39 pm

Mike, what you will need for your A-model is two complete LEFT muffler systems (including risers, clamps, and shrouds), then a left AND right tailpipe. You will not need the heater-adaptor they offer with their right system (which is for the '53/later systems.) You will need the later crossbrace, and throw your original pancake crossbrace away.
The only aircraft that will utilize the right muffler system offered by AWI are the '53 and later B-models.