Think I have found my intake leak.

[RustyNance]

Recently purchased this plane and have been stumped by a lean condition when the engine was hot.  Kinda surprised this wasn't found during the pre-buy, which was concurrent with the annual.  It would appear there is no O-Ring gasket on tube number three.  I'll attach a pic of number three and also number one for comparison.  You can clearly see the red o-ring on number one.  Gonna order up a set of gaskets for that tube today.

V/R

Rusty Nance

[Yetti]

Wonder where it went?  Might want to find it.

[N201MKTurbo]

You would have to be quite the lame brain to do that. 

Sometimes when you are installing the tube you will push it through. It is a real PITA to get it back out and it can pull the O ring off while pulling it out. But you would know that. 

[RustyNance]

8 minutes ago, N201MKTurbo said:

You would have to be quite the lame brain to do that. 

Sometimes when you are installing the tube you will push it through. It is a real PITA to get it back out and it can pull the O ring off while pulling it out. But you would know that. 

Gonna install this one myself and get the mechanic to sign it off.  Not real familiar with the Lycoming, previous airplane had a Franklin in it.  Engine was overhauled about 40 hours ago by previous owner.  No telling where the o-ring ended up but will make an attempt to find it.  I'll put as much light in the box as I can and still fit an inspection mirror.  Odd part is how well the engine has been running.  you really only notice a lean condition when taxiing with a hot engine.  

[kmyfm20s]

When trying to reduce my GAMI spread in my J I went as far as to put a bead of RTV around each one and it helped!

[DualRatedFlyer]

Would be nice to see some pics during the removal/install when you get around to it @RustyNance

[bradp]

Might do better with a bore scope taking a look around.  

[Alan Fox]

Doubt it would run at all with the O-ring missing , In fact ..... It wont.......   Lets see ........  Common sense....... Perhaps the O-Ring is black ?????

[N201MKTurbo]

8 minutes ago, Alan Fox said:

Doubt it would run at all with the O-ring missing , In fact ..... It wont.......   Lets see ........  Common sense....... Perhaps the O-Ring is black ?????

I have had an intake riser fall off like another poster showed. It runs surprising well. It just reduces the airflow through the servo, so the mixture  is off, but you can compensate with the red knob. The engine doesn't care where the air comes from. The servo still supplies fuel to the injectors. It would be a different story with a carbureted engine.

[Tommy]

May I ask what symptoms are you experiencing? 

[RustyNance]

Got the tube off today after work.  the O-ring is definitely bad.  Was broken into at least three pieces.  I found two pieces and even a borescope could not locate the rest.  I ordered a new seal, but it isn't the right size.  Believe I have the wide deck IO-360-AIA as the serial number ends in A.  The new big fat o-ring seal is the one ordered based off the part number in the lycoming parts manual, but it is just to big to even begin to fit.  I tracked down a different part number by cross referencing the entire gasket kit part number that was used during the last overhaul.  The big fat one in the picture is SL77569.  This afternoon I ordered SL74712, which I believe to be the correct seal.  Anyone else experience any parts issues like this?

Regardless, It will be Wednesday before the new seal arrives.  Wish I lived closer to Aircraft Spruce.

I'll post more pics when she goes back together.

V/R

Rusty Nance

[RustyNance]

On 5/15/2018 at 6:00 AM, Tommy said:

May I ask what symptoms are you experiencing? 

Primarily, Popping from the engine when it was hot at idle rpm.

 

[carusoam]

Nice work identifying the problem, Rusty!

 

Next Step... identifying the proper part number from the right parts catalog...

 

At this level, I had found a Lycoming parts manual for my engine.  Ordered the parts through AS.  Delivered the parts to my mechanic for proper installation/torque etc...

 

its been a decade since since I was doing that kind of detail....  Lycoming probably has the parts catalog on line...

 

if nothing else, your mechanic will be able to identify the proper parts for your engine...

Do you have a mechanic you can work with like that?

Best regards,

-a-

[RustyNance]

3 minutes ago, carusoam said:

Nice work identifying the problem, Rusty!

 

Next Step... identifying the proper part number from the right parts catalog...

 

At this level, I had found a Lycoming parts manual for my engine.  Ordered the parts through AS.  Delivered the parts to my mechanic for proper installation/torque etc...

 

its been a decade since since I was doing that kind of detail....  Lycoming probably has the parts catalog on line...

 

if nothing else, your mechanic will be able to identify the proper parts for your engine...

Do you have a mechanic you can work with like that?

Best regards,

-a-

Mechanic is great.  Does owner assisted stuff and kept my Stinson flying for years.  When it comes time for everything to go back together he will be there.  Just saves me a lot of mooney money by tracking stuff like this down myself.  

[RLCarter]

Looking in my Parts Manual the 77569 is the correct O-Ring, I replaced all 4 of mine 3 years ago. I highly recommend the gasket between the Cylinder and Intake Pipe as well p# 71973

[N201MKTurbo]

It looks to me like you have two different versions of intake risers. The new ones that take the big o rings and the old ones that take the skinny o rings. The new ones have the o ring holder braised on sheet metal and the old ones had a machined casting.

[N201MKTurbo]

[MB65E]

Common issue in lycoming IPC.

There are at least 3 different intake o-rings. The IPC mentions only one. In the 540 manuals, it’s the wrong p/N. Turbo has it right, it’s based on the risers, and how many times the plentum has been machined and sleeved. Frustrating for sure!!

-Matt

[RustyNance]

7 hours ago, N201MKTurbo said:

Mine looks like the bottom picture. 

[N201MKTurbo]

1 hour ago, RustyNance said:

Mine looks like the bottom picture. 

Yes, the one you took out. but the first picture you posted shows that the other one is like the top picture.

[RustyNance]

27 minutes ago, N201MKTurbo said:

Yes, the one you took out. but the first picture you posted shows that the other one is like the top picture.

Well, that would certainly contribute to my confusion.  Thanks for the tip.