Aircraft Parts Pricing / Shopping
Posted: Sun Dec 10, 2017 9:12 pm
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. 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.)
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.
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.
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.
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. 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.
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. 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.)
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.
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.
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.
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. 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.