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Posted (edited)

I have been having some wondering EGT numbers for quiet sometime.

Looking in the Ram Air door lastnight I seen an alarming picture.

Im a Propeller Guy, Not a Powerplant Guy.

Im guessing those 4 little tubes are the 60’s version of a Mass Air Flow Sensor.

If that’s an Accurate observation, what would happen if that build up gets inside the tubes?

D047BFA7-553E-4717-AB14-00C556C80457.jpeg

Edited by Cody Stallings
Posted
4 minutes ago, tony said:

do those cracks on the boot go all the way through?

Yes.

we gonna get a new boot coming from Don on Monday.

The oil is coming from a pesky thrubolt leak!.

Posted

The impact tubes are part of the airflow measuring system for the servo and are meant to be clean.  It likely has something to do with your irratic EGT.

Clarence 

Posted
12 minutes ago, N201MKTurbo said:

I've cleaned them with brake parts cleaner (red) and it will get better for a while. You better start planning for an overhaul.

The break cleaner will not damage anything inside the Servo?

Also, where does it go after it settles?

Posted

The impact tubes since the airflow into the engine ( like the pitot tube) and adjust the fuel pressure inside the servo. The tubes lead to one side of a diaphragm and that has no outlet. I would not think very much of the debris would get there since the air is static or almost. I would not use anything stronger than avgas to clean it if I were doing it.  

 

 

 

  • Like 1
Posted

Hi Cody,

the oil must be from a little oil leak on the engine or how funny is this? A leak in the prop. Lol

the oil is getting in through the cracks and when the dust and dirt are sucked in the oils catching the dirt. I would replace the intake bellows.  Lycoming says something like a teaspoon of dirt is enough to cause wear that will need an overhaul. Make sure your ram air closes all the way with no leaks. The problem with EGTs wondering could be the servo but check the cheap stuff first. 

Do all EGTs rise at the same time? Only one cyl? Do you have engine monitor data?  Lean mag check data?  

Jim

Posted
4 hours ago, Cody Stallings said:

The break cleaner will not damage anything inside the Servo?

Also, where does it go after it settles?

Like others say, if you shoot solvent into the tubes it will get stuck inside the servo. You just want to wash it off a little. If you  put a rubber hose on one and gave it a little mouth pressure while you sprayed the rest you should be able to blow any that got inside out before it evaporates. 

The only good way to clean it is to disassemble it, which means overhaul.

Also try not to get any of the TCE in your mouth it is a bit carcinogenic. 

I doubt the brake cleaner will hurt anything in the servo, but washing a bunch of crud into it may.

Posted
9 hours ago, Jim F said:

Hi Cody,

the oil must be from a little oil leak on the engine or how funny is this? A leak in the prop. Lol

the oil is getting in through the cracks and when the dust and dirt are sucked in the oils catching the dirt. I would replace the intake bellows.  Lycoming says something like a teaspoon of dirt is enough to cause wear that will need an overhaul. Make sure your ram air closes all the way with no leaks. The problem with EGTs wondering could be the servo but check the cheap stuff first. 

Do all EGTs rise at the same time? Only one cyl? Do you have engine monitor data?  Lean mag check data?  

Jim

Yes all egts float around about the same amount(EDM 700).

I have not downloaded the data though.

Posted
On 12/13/2017 at 7:22 PM, Cody Stallings said:

Yes.

we gonna get a new boot coming from Don on Monday.

The oil is coming from a pesky thrubolt leak!.

So, I'm wondering if that would change the airflow sporadically and give you the issue you are experiencing.  I would fix that first the see what you have.

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