Aircraft Parts Pricing / Shopping

How to keep the Cessna 170 flying and airworthy.

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GAHorn
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Aircraft Parts Pricing / Shopping

Post by GAHorn »

While performing the annual inspection repairs on the 172 I recently purchased, I discovered the carb-heat butterfly-valve seal deteriorated (helped along by the leaking heat from the defective mufflers constantly pumping heat into the airbox, I'm sure.) The rubberized-fabric which forms the seal is hardened and portions missing.... Probably ingested by the engine at some point, likely long ago.

So.... removing the airbox proved to be a half-day effort. It's a different airbox than on the 170. This pic is showing one for salvage-sale in an upside-down position.
AirBox0550180-1.jpg
There are actually TWO valves...the one seen in the pic (the black rubber-fabric seal is what's missing on mine) and looking at the rear of the box, there is a 3" hose-flange visible... NOT visible is another 3" hose-flange exactly opposite. The lever on the bottom of the box operates a door which normally allows the hot air from the left muff to cross thru the box to the cabin heat valve on the right side of the airplane. Pulling carb-heat operates a side-lever (not visible) that flips the butterfly valve which is visible to shut off filtered air and admit hot air... and pulling the carb-heat simultaneously operates that bottom lever (seen above) which operates an internal door shutting off the left muff-to-cabin-heat and directing left muff heat into the carburetor.

Removing this airbox was a pain because the flange by which it attaches with four nuts to the bottom studs on the carb inlet has insufficient room to twist the nuts. They must be removed one-nut-at-a-time...and.... one-flat-at-a-time. The nuts will not come off the studs until all four are spun completely to the point of jamming against the airbox below the flange. (I have put-off thinking about how in the heck I'm going to get it back on.) :cry:

OK...so I got it off and sent out for repair. The problem is ordering that simple little gasket which sits between the airbox and the carburetor inlet/throat.
airbox.jpg
The Cessna IPC for the airplane shows PN0750142-1 (not depicted in the pic above...but listed in the parts listing as "gasket, carburetor airbox".

Aircraft Spruce has it...http://www.aircraftspruce.com/catalog/a ... ckkey=5189.... Priced at (are you sitting down?).... $79.95. 8O

I couldn't believe this was not a typographical error so... I checked with Cessna.

Cessna Parts also has it... priced at a DISCOUNT to 170 Assoc'n Members at $64.95. :evil:

I figured it must be made of something very exotic so I used my pocket knife to shave the damaged remains off the bottom of the carb and it looks like heavy paper to me.

I called Spruce and talked to two different persons... the first person assured me the price was correct and seemed disinterested in my request for her to go get one off the shelf and see if it was only a simple gasket or if it had something extraordinary about it. She said she'd call me back and after several hours I called again and got a different person.
This second person offered to call me back and when she did.... she said she can not tell the difference between that part number.... and another CONTINENTAL part number...21323....that sells for $2.90.... and which correlates to a SUPERIOR Part Number that sells for 70-cents.
PN21323
PN21323
CarbHeatTCMgasket.jpg (18.15 KiB) Viewed 16146 times
Sooooo.... Whether the part is searched for using a Cessna PN, a TCM PN, or a Superior PN.... makes a BIT of a difference on the price. 8O
'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. ;)
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c170b53
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Re: Aircraft Parts Pricing / Shopping

Post by c170b53 »

I have that same air box George, isn't it a beauty! I think I installed a stud in one of the bolt holes and drilled a nut for
lockwire, just to make it a bit easier to install. I also have a new carb heat / cabin heat control cable, it's probably worn lots since it's a Cessna part but like many Cessna parts it's only worn what someone is willing to pay for it.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
marathonrunner
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Re: Aircraft Parts Pricing / Shopping

Post by marathonrunner »

I make my own gaskets. At a nickel an hour I save a lot of money
It's not done till it's overdone
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GAHorn
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Re: Aircraft Parts Pricing / Shopping

Post by GAHorn »

c170b53 wrote:I have that same air box George, isn't it a beauty! I think I installed a stud in one of the bolt holes and drilled a nut for
lockwire, just to make it a bit easier to install. I also have a new carb heat / cabin heat control cable, it's probably worn lots since it's a Cessna part but like many Cessna parts it's only worn what someone is willing to pay for it.

Is THIS the airbox you have Jim?
LongAirbox.jpg
'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. ;)
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c170b53
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Re: Aircraft Parts Pricing / Shopping

Post by c170b53 »

Almost the same George. As you have found there's almost no room for the four attach bolts to mount it to the carb base.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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GAHorn
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Re: Aircraft Parts Pricing / Shopping

Post by GAHorn »

Jim, what serial is the airplane we're discussing with a "long" airbox? (The one I depicted is an early C-175. Later 175-C models, with cowl flaps, CS prop used a different box which had a flexible plenum. We modified a friends to use a ruuber sewer-hose fitting that greatly improved the cowl fitment.)
'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. ;)
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c170b53
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Re: Aircraft Parts Pricing / Shopping

Post by c170b53 »

1958 straight tail 175. Box was surplus after that plane had a Lycoming conversion and was put on floats
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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GAHorn
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Re: Aircraft Parts Pricing / Shopping

Post by GAHorn »

c170b53 wrote:1958 straight tail 175. Box was surplus after that plane had a Lycoming conversion and was put on floats
Well...if you still have it... good used condition it's worth $1K and ovhl'd it's worth $2300. (If you send it to me, I"ll cut off the extension and buy you a beer. or two. or...) :lol:
'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. ;)
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