How to check for intake leaks

How to keep the Cessna 170 flying and airworthy.

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twlareau
Posts: 68
Joined: Fri May 13, 2011 3:20 am

How to check for intake leaks

Post by twlareau »

I'm sure someone on this forum has check their intakes for leaks. Has anyone tried the soapy water methods? My understanding is that you tape off the carbuator air box to prevent leakage and then use a compression tester to compress a cylinder on the intake stroke there by pressurizing the intake manifold. This process seems right to me but then again I've never done it. Any suggestions would be appreciated.
WSHIII
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Joined: Mon Feb 18, 2013 7:02 pm

Re: How to check for intake leaks

Post by WSHIII »

Or use the exhaust side of a "shop Vac" (with a CLEAN filter), plugged into the airbox to pressurize the intake system

Another option, however, one that is much more dangerous for obvious reasons. Nonetheless, one that I find quicker, easier and more diagnostic but is not for everyone. Spray/squirt Ether, WD40, Carb Cleaner, etc,............ around the intake couplings, intake flanges, while the engine is running and watch for an increase in RPM's. Might want to have a fire extinguisher on standby. 8O
N8034A '52 170B #20886
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ghostflyer
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Re: How to check for intake leaks

Post by ghostflyer »

Using the squirter but filled with water and a large amount of detergent mixed is a little safer than using a hydrocarbon .
twlareau
Posts: 68
Joined: Fri May 13, 2011 3:20 am

Re: How to check for intake leaks

Post by twlareau »

I used the vacuum method and it worked great! Thanks for the tip. No intake leaks to be found so I decided to put the shop vac on the exhaust, lo and behold leaks everywhere. I expected to fid some leaks around the clamps but I also found leaks around the flanges of four risers. My flanges were awfully thin. No cylinder damage yet but im sure it would only been a matter of time. I called AWI in Minneapolis and ordered a whole new exhaust system. I talked to Charlie, it turns out we used to work together a couple of decades ago! Small world. I will post pics of the new exhaust when I get it.
Last edited by twlareau on Thu Aug 01, 2013 3:55 am, edited 1 time in total.
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GAHorn
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Re: How to check for intake leaks

Post by GAHorn »

Charlie Field at AWI does good work and has a good attitude. Additionally, AWI donated an entire exhaust system to us for the Kelowna convention.
'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. ;)
twlareau
Posts: 68
Joined: Fri May 13, 2011 3:20 am

Re: How to check for intake leaks

Post by twlareau »

Charlie was and is a class act, I was glad to give his company some business and that was one heck of a donation to the association.
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