Thanks, I'll look for that stuff. I may be able to secure a pancake muffler replacement (in good shape) from another 170 that simply upgraded to the H-W system for the increased heater output. I will see them in a few days and determine if they will do the trick (safely) ... for quite a few pennies less .
I think I saw on another post of someone submerging a muffler to check for cracks. Is that a valid test? I suppose you just tape up the ends and submerge it just like a bicycle tube and look for air bubbles. Of course I will give it a very close visual inspection before proceding with any other shenanigans.
I've never heard of that method, and wouldn't place much trust in it either. You'd have to pressurize the system to test it.
One such test, widely used, is to use a vacuum cleaner exhaust to pressurize the system with soap-bubbles, to look for leaking foam. One advantage of such a test method is that it can be done "in situ" (still installed.)
The drawback is that it is only a short-term validity. Without a visual inspection on the bench, it's difficult to determine the structural soundness of the system. (Sorta like a guerrilla-weld.... If you can pick it up, slam it down, and shake it, and it still sticks together....you're good to go!)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
Mike Smith wrote:On the cross brace issue, my pancakes didn't have any cross brace. Does this mean I will not need one for the H-W's?
It simply means your cross-brace is missing. The cross-brace's purpose is to alter the vibration harmonics of the exhaust system in order to reduce a cracking problem. The HW exhausts required a different cross-brace because they have a different harmonic frequency. The crossbrace was installed as the result of an early SNL (Service News Letter) that called for it's installation as a retrofit to HW conversions, and announced it's inclusion on aircraft being factory-equipped with HW.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
I talked with AWI today and they are shipping my new mufflers and all associated hardware ... but they didn't know anything about the crossbrace. I tried to explain it to him but he didn't know anything about it. Has anyone else ordered from AWI and recieved this part? I was looking around for a picture or drawing of the part but can't find one. I have an "A" model so I don't have the "B" model IPC ... I have the IPC for an "A" model. I'll call back tomorrow and give him the part number from above (PN#0550159) and see if that gets me anywhere.
Mike, it's not an exhaust part, so I don't expect them to have it.
It's an airframe part,(illustrated as part of the engine installation) found on pg 86 of the B-model IPC, item 13, PN 0550159 for aircraft prior to sn 25764, or PN 0550159-5 for aircraft after sn 25764.
You can probably make the early one pretty easily. It's merely a straight piece of 1/4" I.D. steel tubing with it's ends pressed closed (and a hole drilled thru those flats) to accept the AN3 bolt which connects it to the left and right tailpipes at their clamps-to-the-muffer, and then it has a single "tab" (a simple non-cushioned Adel clamp would probably do the trick) which connects it (as it passes directly in front of the carb) to the left/fwd carb-mount bolt.
Last edited by GAHorn on Thu May 11, 2006 8:09 am, edited 1 time in total.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
I haven't yet installed the carburetor or exhaust system on my overhaued engine, so my brace is still laying around loose. If I can remember to take the camera to the airport this evening or tomorrow, I'll take a picture of it on grid paper so you can get a feel for the size and shape.
Miles
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
Or simply order the superceded part number from Cessna. It's merely 0550179-1 TUBE
(List Price: $ 336.00) Stock Available $ 268.80 (EA)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
Hope this helps. Just remember that the outboard ends bolt to the clamps that holds the exhaust stacks to the bottom of the muffler, and the bracket toward the middle fits over the left front carburetor attach stud. Make sure you get the angles right; nothing seems to be parallel or perpendicular to anything else.
Miles
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
Miles, I'm having a bit of difficulty with that picture. It appears to be of PN 0550125 for pancake muffs. The PN 0550159 for the Hanlon Wilson's is a fairly straight tube.
If that is off your airplane,....does it mount to the FORWARD bolt of the carb? (The earlier brace mounts to the rear of the carb.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
gahorn wrote:Miles, I'm having a bit of difficulty with that picture. It appears to be of PN 0550125 for pancake muffs. The PN 0550159 for the Hanlon Wilson's is a fairly straight tube.
If that is off your airplane,....does it mount to the FORWARD bolt of the carb? (The earlier brace mounts to the rear of the carb.)
This is actually the brace from my "interim engine", the C-145, which was original to a 1952 B-model. The C-145 had Hanlon Wilson's on it when I bought it, although the right one (cabin heater) was the old style with 2-inch ducting. I replaced that side with the 3-inch style from my original O-300 and the above brace fit perfectly, using the front left carb attach stud, and the inboard sides of each of the tailpipe clamps. The brace that was on my airplane when I bought it is very similar to this one execept that it had been kinked at one of the angles to make it fit.
I'll hopefully be installing the exhaust system in a day or two and I'll make it a point to take a picture with the brace in place.
Miles
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
Hold on ... terminate the emergency I found the part on Cessnaparts.com and had it shipped out. They were real nice on the phone and to cut some time were able to have Cessna ship it directly to me from Wichita to California instead of KS-GA-CA and losing a day or two in the process. Hopefully I'll be aviating by this weekend
Cessna® is a registered trademark of Textron Aviation, Inc. The International Cessna® 170 Association is an independent owners/operators association dedicated to C170 aircraft and early O-300-powered C172s. We are not affiliated with Cessna® or Textron Aviation, Inc. in any way.
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The cross-brace's purpose is to alter the vibration harmonics of the exhaust system in order to reduce a cracking problem. The HW exhausts required a different cross-brace because they have a different harmonic frequency. The crossbrace was installed as the result of an early SNL (Service News Letter) that called for it's installation as a retrofit to HW conversions, and announced it's inclusion on aircraft being factory-equipped with HW.
I found the part on Cessnaparts.com and had it shipped out. They were real nice on the phone and to cut some time were able to have Cessna ship it directly to me from Wichita to California instead of KS-GA-CA and losing a day or two in the process. Hopefully I'll be aviating by this weekend